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1. © 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 1 35 PROCEDURES FOR RECTAL CANCER David A. Rothenberger, M.D., F.A.C.S., and Rocco Ricciardi, M.D. Rectal cancer is a common and lethal malignancy that is diag- or genitourinary organs); previous irradiation of the pelvis; base- nosed in more than 42,000 persons in the United States each line bowel and anal sphincter function; smoking status; use of year.1 In treating this condition, the goals are to cure or control alcohol or other drugs; medical comorbidities; and current med- the primary cancer, to maintain or restore bowel continuity with ications. In particular, a family history suggestive of a hereditary normal anal continence, to preserve sexual and bladder function, cancer syndrome should be sought because such a history might and to minimize other treatment-associated morbidity and mor- call for additional diagnostic testing or affect the extent of bowel tality. A variety of rectal cancer treatment regimens are now avail- resection. able, spanning the spectrum from simple polypectomy to pro- During the physical examination, the surgeon should be alert longed and potentially morbid multimodality regimens involving to the presence of liver enlargement, abdominal tenderness or neoadjuvant chemoradiation therapy, radical extirpative surgery, masses, lymphadenopathy, and abdominal scars or ventral her- and adjuvant chemotherapy. nias from previous operations. The integrity and function of the Choosing the optimal therapy for rectal cancer is a complex anal sphincter are carefully assessed by means of digital rectal process. Although physicians from different disciplines are often examination. A patient with preexisting fecal incontinence or involved, it is the colorectal surgeon who generally directs the sphincter injury may be best served by a local procedure or process of evaluation and treatment. As new knowledge has been abdominoperineal resection (APR) rather than a well-intentioned acquired and new therapies and techniques have been developed, but ill-conceived heroic effort to save the anal sphincter. management of rectal cancer has changed dramatically. In this DETERMINATION OF EXTENT OF LOCAL DISEASE chapter, we examine the surgeon’s unique and critical role in the preoperative decisions leading to choice of therapy, review the Evaluation of the extent of the primary rectal cancer is essen- intraoperative decisions inﬂuencing the course of surgical thera- tial for planning appropriate therapy. An easily palpable distal rec- py, and address key technical aspects of the operations performed tal malignancy that directly invades the anal sphincters usually is to treat rectal cancer. treated with APR. A large, ﬁxed cancer that invades adjacent organs, the pelvic sidewalls, or the sacrum usually is treated with neoadjuvant chemoradiation followed by resection or palliative Preoperative Evaluation measures. A small, mobile, and readily accessible lesion may be Evaluation of the patient with rectal cancer includes the follow- amenable to local therapy. ing: (1) visualization of the tumor and biopsy to determine the pre- Determination of the extent of local disease involves clinical cise location of the lesion and conﬁrm the diagnosis of adenocar- examination, endoscopic assessment, and diagnostic imaging. cinoma; (2) accurate staging of the neoplasm by determining the Digital rectal examination, combined with proctoscopy, endorec- extent of bowel wall penetration (T stage), the presence of metas- tal ultrasonography (ERUS), or magnetic resonance imaging, can tases to local lymph nodes (N stage), and the presence of metasta- determine the morphology of the lesion, the percentage of the tic spread to distant sites (M stage); (3) colonoscopy to exclude rectal circumference involved, and the quadrants affected, as well synchronous lesions or other pathologic conditions of the colon; as the degree of ﬁxation, the adjacent organs invaded, and the and (4) a thorough medical assessment to determine operative risk. presence of lymph nodes or extrarectal masses. The level of the A standardized workup facilitates staging and decision making. lesion in relation to the anal sphincters is best assessed by means of digital rectal examination and ERUS or endorectal MRI. The HISTORY AND PHYSICAL EXAMINATION distance of the lesion from the dentate line or the anal verge is A thorough history and a careful physical examination must be assessed more accurately with rigid proctoscopy than with ﬂexi- done to assess operative risk so that therapeutic options can be ble endoscopy. Biopsy is required to conﬁrm the suspected diag- tailored to ﬁt the comorbidities and desires of the patient. In nosis of adenocarcinoma and to ascertain whether any unfavor- modern series, mortality after radical resection of the rectum able histologic features (e.g., mucin production, lymphovascular ranges from 2% to 6%,2,3 with the most common causes of death invasion, or signet cell histology) are present. being myocardial infarction, pneumonia, venous thromboem- ERUS and MRI with endorectal coil are the two most useful bolism (deep vein thrombosis and pulmonary embolism), anas- methods of determining the T and N stages of rectal cancer. In a tomotic leakage, and stroke.4 Factors associated with increased combined review of 1,966 patients evaluated with ERUS, staging mortality include impaired sensorium, low albumin level, elevat- accuracy averaged 88%.5 ERUS was highly (80% to 90%) accu- ed blood urea nitrogen concentration, and prolonged prothrom- rate in predicting the extent of bowel wall involvement but was bin time.3 somewhat less (70% to 80%) accurate in identifying lymph node The history focuses on gaining information that might alter metastases.6 Currently, MRI with endorectal coil, though promis- the treatment plan or identify preexisting conditions worth ing, is accurate in only 40% to 60% of cases; accordingly, it has not addressing before an elective procedure. Essential information to replaced ERUS for staging the extent of local disease.7,8 Newer be elicited includes a personal history of colorectal polyps or can- MRI approaches that employ stronger magnets and do not require cers; previous operations (especially those involving the digestive insertion of an endorectal coil may prove more accurate. ERUS
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 2 has the added advantage of offering a convenient and accurate contrast barium enema or virtual colonoscopy with CT cologra- means of performing image-directed biopsies of suspicious areas. phy is a suitable alternative. If preoperative surveillance of the Pelvic computed tomographic scanning is not very accurate in proximal colon is not possible, intraoperative or postoperative determining the depth of bowel wall involvement or the presence colonoscopy should be done. of lymph node metastases: the highest accuracy reported for CT in this setting is approximately 76%,9 and most studies report much lower ﬁgures. Pelvic CT scanning is, however, useful for Operative Planning detecting extrarectal pelvic spread from rectal cancer. Presacral PRETREATMENT DECISIONS stranding, obliteration of normal landmarks lateral to the rectum, direct invasion of the sacrum or the pelvic sidewalls, invasion into In general, the surgeon is responsible for deciding what the the bladder or the vagina, and evidence of hydronephrosis are all intent of therapy will be (curative or palliative) and which treat- signs of extensive pelvic disease. ment or treatments will be employed.To make these decisions, he or she must carefully consider the clinical staging information in SEARCH FOR DISTANT METASTASES the light of the anticipated operative technical challenges, the like- Evaluation of the patient with rectal cancer must also include ly functional results, and the patient’s level of operative risk, a search for metastatic disease because the approach to the pri- comorbidities, previous treatments, and speciﬁc needs. mary lesion may change if metastases are present. Few data are Clinical staging is based on integration of information available on the utility of palliative rectal cancer surgery in the obtained from several sources, including clinical evaluation, setting of metastatic disease; however, it is generally accepted that imaging studies (e.g., ERUS, CT, MRI, and PET), colonoscopy, patients who present with asymptomatic or minimally sympto- and histopathologic examination of the specimen obtained via matic distant metastases but who have major local symptoms biopsy or local excision. Because the information on which it is resulting from the primary rectal cancer may beneﬁt from some based is obtained before institution of deﬁnitive treatment, clini- form of palliative operation. As a rule, the least morbid procedure cal staging is necessarily a less than perfect means of assessing the that will relieve the local symptoms is preferred. Often, the cho- extent of disease. Nonetheless, it usually sufﬁces to allow the sur- sen procedure is palliative proctectomy, but sometimes, a less geon to decide whether the intent of treatment will be curative or invasive local procedure (e.g., stenting) is an option. Patients who palliative and whether a local procedure, a radical procedure, or present with advanced and highly symptomatic distant metas- multimodality therapy will be indicated. tases but who have an asymptomatic primary rectal cancer are A history of previous cancer treatment may inﬂuence the usually best served by therapy directed toward the symptomatic choice of therapy, as may the presence of synchronous lesions, metastases. The presence of extensive but minimally sympto- metastatic disease, extensive local spread, or unfavorable matic metastases and a minimally symptomatic primary cancer histopathology. Not infrequently, the ideal treatment is not of the rectum may mandate use of nonoperative, palliative treat- feasible—either because of patient risk factors and comorbidi- ment regimens. ties or because the patient refuses to accept the proposed treat- Distant metastases arise most frequently in the liver and the ment and its associated morbidity (e.g., a permanent colosto- lungs and are often asymptomatic; accordingly, routine evalua- my)—and the treatment eventually chosen represents a com- tion for distant disease focuses on assessment of these two sites. promise. The experienced surgeon can counsel the patient If patients have speciﬁc symptoms suggestive of possible metas- about therapeutic options, realistic expectations, and likely tases to other organs or sites, additional imaging studies are prognosis and obtain informed consent to proceed with a ordered to explore this possibility. Chest x-ray and CT scanning treatment protocol that is individualized to the speciﬁcs of a are the modalities most commonly employed to identify pul- given case. monary metastases; CT and MRI scanning are the ones most TREATMENT PROTOCOLS AND MULTIMODALITY THERAPY commonly employed to identify liver metastases. An alternative modality, positron emission tomography (PET), has proved high- Because treatment of rectal cancer is so highly individualized, ly (96%) sensitive in detecting the primary cancer but is of limit- it is difﬁcult to be dogmatic about what constitutes optimal ther- ed value in detecting local pelvic lymph node metastases.10 Some apy. Nonetheless, there are certain generally accepted treatment advocate using PET to detect other organ metastases or involve- guidelines for curative-intent treatment of rectal cancer, based ment of lymph nodes at distant sites. At present, however, there primarily on pretreatment stage of disease, that are useful for the is little evidence to justify routine use of PET scanning in the practicing surgeon [see Table 1].12,13 Curative-intent treatment of workup of rectal cancer. Its major current uses are (1) to clarify rectal cancer involves resection or ablation of all neoplastic tissue, equivocal ﬁndings on other scans and (2) to minimize the risk of which almost always necessitates surgical intervention, usually in missing a distant metastasis to an unusual site in a patient being the form of a radical resection. In highly select cases, local thera- considered for a highly morbid resection of an extensive primary py may be indicated. Currently, multimodality therapy that com- or recurrent rectal cancer. bines operative treatment with perioperative chemoradiation is increasingly being employed to overcome the persistent problem ASSESSMENT OF SYNCHRONOUS COLORECTAL NEOPLASMS of local recurrence. Total colonoscopy is recommended to exclude or remove syn- Clinical trials designed to assess the efﬁcacy of postoperative chronous lesions (e.g., polyps and other cancers). It is estimated adjuvant pelvic irradiation in treating advanced cancers of the that 5% to 10% of rectal cancer patients have synchronous can- rectum demonstrated that appropriate doses of radiation can cers and 30% have additional adenomatous polyps. The signiﬁ- reduce local recurrence and even improve survival, especially cance of these other lesions is highlighted by a study of 98 when administered in conjunction with radiation-sensitizing patients with rectal cancers who underwent full colonoscopic sur- chemotherapy and postoperative adjuvant chemotherapy.14-17 In veillance before operation; in this study, surgical treatment was the United States, most centers administer 45 to 54 Gy of radia- altered in 33% of cases.11 If colonoscopy is incomplete, a double- tion to the rectal cancer and the pelvis over a period of 4 to 6
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 3 Table 1 Rectal Neoplasms: Curative-Intent Therapy Pretreatment Stage Preferred Treatment Acceptable Treatment Stage 0 Tis N0 M0 Local therapy if technically feasible (excision is preferred to ablation Radical resection (APR rarely indicated for Tis N0 M0 lesion) if local for obtaining pathologic confirmation of T stage) therapy is not feasible or safe Stage I T1 N0 M0 (favorable features*) Local therapy ± chemoradiation for distal-third lesions or high-risk Radical resection patients; radical resection for proximal lesions in good-risk patients T1 N0 M0 (unfavorable features) Radical resection Local therapy plus chemoradiation T2 N0 M0 Radical resection (especially if unfavorable features are present and Local therapy plus chemoradiation for proximal lesions in good-risk patients) Stage II T3 N0 M0 Preoperative chemoradiation, radical resection, and adjuvant Radical resection, postoperative chemoradiation, and adjuvant chemotherapy chemotherapy if pathologically appropriate (no adjuvant therapy if lesion is early T3 N0 M0) T4 N0 M0 Preoperative chemoradiation, radical resection with en bloc resec- Radical resection, postoperative chemoradiation, and adjuvant tion of involved organs, and adjuvant chemotherapy chemotherapy Stage III Tany N+ M0 Preoperative chemoradiation, radical resection, and adjuvant Radical resection, postoperative chemoradiation, and adjuvant chemotherapy chemotherapy *Lesions with favorable features are those that are exophytic, moderately or well differentiated, nonmucinous, non–signet cell, without lymphovascular invasion, extending around one quar- ter or less of the circumference of the rectum or no more than 3 cm in diameter, and located so that local therapy options are technically feasible and safe. PATHOLOGY-BASED STAGING AND POSTTREATMENT weeks. A 1990 National Institutes of Health consensus conference DECISIONS endorsed postoperative multimodality treatment of all stage II and III rectal cancers.18 Clinical staging that is based on pretreatment assessment must Several researchers have assessed the use of preoperative be distinguished from pathology-based staging that relies on neoadjuvant chemoradiation in treating advanced-stage rectal information obtained by means of gross and microscopic exami- cancers.19,20 It was argued that because preoperative irradiation nation of the resected rectal tumor and the surrounding mesorec- treats undisturbed, well-oxygenated rectal cancers, it should be tum after radical excision. The classic pathology-based staging more effective than postoperative irradiation, resulting in system developed by Dukes correlated patient survival with depth improved local control and better survival. In addition, it was of rectal cancer invasion and local lymph node metastases.24 argued that by decreasing the size of bulky rectal cancers, preop- Many modiﬁcations to the Dukes staging system were proposed, erative irradiation should increase the rate of curative resection but it remained the most widely used system until 1987, when the and the rate of sphincter preservation.21 It was also thought that American Joint Committee for Cancer Staging and End Results this neoadjuvant approach should diminish the incidence of the Reporting (now the American Joint Committee on Cancer radiation injury seen after postoperative irradiation when small [AJCC]) developed a new classiﬁcation methodology that incor- bowel is adherent to the pelvic operative site.22 Whereas centers in porated both relevant clinical information and pathology-based the United States tended to employ a prolonged course of irradi- information.25 The AJCC’s proposed TNM classiﬁcation system, ation both preoperatively and postoperatively, many European which has been adopted by the International Union Against centers, especially in Scandinavia, preferred to use a protocol of Cancer, is clinically useful, simple to use, and accepted worldwide preoperative short-course, high-dose, hypofractionation irradia- [see Tables 2 and 3]. tion, which usually delivered 25 Gy over a period of 1 week.23 An important principle in managing patients with rectal cancer There is now considerable evidence that chemoradiation can is to compare the pretreatment clinical stage with the ﬁnal pathol- decrease local recurrence rates after radical procedures for rectal ogy-based stage to conﬁrm the appropriateness of the proposed cancer and that it may improve survival and decrease the need for treatment protocol or to adjust therapy on the basis of new infor- a permanent colostomy. To date, most studies have used 5-ﬂuo- mation. There is some evidence to indicate that patients who rouracil–based chemotherapy for radiation sensitization; studies undergo radical procedures immediately after local excision of a using newer agents may be able to obtain further improvements tumor with unfavorable pathologic characteristics survive longer in outcome.17 The success achieved by employing perioperative than those who undergo radical resection after a local recur- chemoradiation in conjunction with radical surgery has led to the rence.26 The ﬁnding of a more advanced T stage after local thera- use of perioperative chemoradiation with local excision in several py may induce the surgeon to proceed with radical resection or to centers. These promising results must be weighed against the add postoperative chemoradiation to the treatment protocol. The short- and long-term morbidity associated with chemoradiation. ﬁnding of a less advanced T stage after local therapy may induce At present, the main controversies in the selection of multimodal- the surgeon to recommend observation rather than risk the mor- ity therapy for rectal cancer are (1) the tumor selection criteria, bidity associated with planned chemoradiation. The presence of (2) the timing of therapy (preoperative or postoperative), (3) the unsuspected multiple lymph node metastases in the mesorectum dosing and course of radiation therapy, and (4) the use of after radical resection of a T2 cancer may dictate use of postoper- chemoradiation in conjunction with local therapy. Discussion of ative chemoradiation. Whether a complete clinical response to these controversies and other issues surrounding the application neoadjuvant preoperative chemoradiation therapy for advanced- of chemoradiation and adjuvant chemotherapy in the setting of stage rectal cancer obviates radical resection is an issue that rectal cancer is beyond the scope of this chapter. remains to be resolved.
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 4 Table 2 American Joint Committee on Cancer Proponents of curative-intent local therapy suggest that it is TNM Clinical Classification of Colorectal Cancer 76 possible to restrict such therapy to select T1 and T2 rectal cancers that do not have associated lymph node metastases. It is known Stage Description* that the incidence of lymph node metastases correlates most closely with the depth of rectal wall invasion and is especially high Tis Carcinoma in situ if the cancer extends through the wall. These proponents argue T1 Invades submucosa that preoperative staging with ERUS or MRI can differentiate Primary tumor (T) T2 Invades muscularis propria intramural (T1–2) cancers from transmural (T3) cancers with a T3 Invades serosa high degree of accuracy33 and can distinguish most of the T1 and T4 Invades peritoneal cavity or adjacent organ through serosa T2 cancers in which lymph node metastases are present. In addi- tion, they note that poorly differentiated tumors recur three times NX Nodes cannot be assessed more often than well-differentiated to moderately differentiated Regional lymph N0 No regional node metastases nodes (N) tumors34 and that lymph node metastases are more common if N1 1–3 positive nodes preoperative biopsy reveals poor differentiation, lymphovascular N2 4 or more positive nodes invasion, mucin production, or signet cell histology. Accordingly, N3 Positive central nodes they recommend avoiding curative-intent local therapy if any of Distant metastasis (M) MX Cannot assess metastases these unfavorable histologic characteristics are present, if imaging M0 No distant metastases studies suggest involvement of lymph nodes, or if the cancer is M1 Distant metastases present transmural, arguing that occult lymph node metastases are rarely *Suffix “m” is used to indicate primary tumors in a single site; prefix “y,” to indicate cancers present if such stringent selection criteria are used. Furthermore, classified after pretreatment; prefix “r,” to indicate tumors that have recurred; and prefix “a,” advocates of curative-intent local therapy suggest that close post- to indicate staging at autopsy. treatment follow-up will detect any local cancer development aris- ing from occult nodal disease at a point where salvage therapy can CHOICE OF PROCEDURE still be instituted. Local Procedures It was hoped that by using these strict criteria for initiating curative-intent local therapy, T1–2 N0 M0 lesions amenable to The beneﬁts of local procedures for treatment of rectal cancer such therapy could be reliably identiﬁed. Unfortunately, this include minimal morbidity and mortality and rapid postoperative hope has not been realized [see Local Procedures, Operative recovery. Such procedures allow preservation of genitourinary Technique, Local Excision, below]. The poor outcomes reported function and cause only minimal disturbance of anal continence. after local excision of select T1 and T2 cancers of the rectum In some cases, local therapy is the only alternative to permanent have prompted several centers (including our own) to limit the colostomy. The major disadvantage of local procedures is that use of curative-intent local therapy by restricting it to favorable employing them inappropriately will result in high local recur- T1 tumors as staged by ERUS or MRI. Some surgeons recom- rence rates and compromised survival. Local procedures may be mend further subdividing T1 lesions on the basis of submucosal used as curative-intent therapy for rectal cancer or as compromise invasion and employing local therapy only for those lesions that therapy for patients who might not tolerate a radical procedure or extend into the superﬁcial third or the middle third of the sub- who refuse a recommended radical resection (usually because of mucosa.35,36 Ideally, strictly limiting the indications for local the potential for a permanent colostomy). Local therapy may also therapy should retain the advantages (e.g., low morbidity) while be used in select cases for palliation of symptomatic but incurable minimizing the disadvantages (e.g., high local recurrence rates), rectal cancers. but further studies are needed to determine whether this will be Curative-intent local therapy is usually restricted to treatment an effective strategy. Clearly, the key to more appropriate use of of highly favorable, accessible rectal cancers that do not invade the local therapy lies in ﬁnding better means of predicting the pre- anal sphincter, are conﬁned to the rectal wall, and are small cise TNM stage and biologic behavior of rectal cancers before enough to be totally removed or ablated. Any spread to local initiating therapy. lymph nodes or distant sites is a contraindication to curative- intent local therapy. In theory, preoperative selection of such favorable T1–2 N0 M0 cancers for local treatment should result Table 3 American Joint Committee on Cancer in minimal morbidity, excellent function, and long-term cancer- free survival. Staging System for Colorectal Cancer76 Critics of local therapy note that on the basis of ﬁnal patholo- gy-based staging after radical resection, as many as 12% of Stage T N M patients with T1 cancers and 22% of those with T2 cancers have Stage 0 Tis N0 M0 node-positive disease that would not have been treated by local procedures.27-32 These critics suggest that imaging studies cannot Stage I T1, T2 N0 M0 reliably distinguish node-negative from node-positive T1 and T2 Stage IIA T3 N0 M0 rectal cancers and that treating all T1 and T2 rectal cancers with local therapy would result in dramatic increases in local recur- Stage IIB T4 N0 M0 rence rates and unacceptable decreases in survival rates. Thus, Stage IIIA T1, T2 N1 M0 they argue that using local therapy as the only form of curative- Stage IIIB T3, T4 N1 M0 intent treatment is inappropriate even for presumed early rectal cancer. Some authorities maintain that curative-intent local ther- Stage IIIC Any T N2 M0 apy should be employed only in conjunction with multimodality Stage IV Any T Any N M1 therapy, even for favorable T1 lesions.
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 5 Radical Procedures harbor invasive cancer.With such lesions, it is occasionally helpful The majority of patients with operable rectal cancer require a to use a large-diameter rigid proctoscope to facilitate snare radical proctectomy. The primary goal of radical resection is to polypectomy. The goal is to remove the polyp in one piece and remove the rectal cancer, the rectosigmoid mesentery, and the provide the pathologist with a properly oriented specimen. If the mesorectum with clear margins. Curative-intent radical resections endoscopist has any suspicion that the polyp may harbor a malig- may be classiﬁed on the basis of the ﬁnal pathologic assessment as nancy, the polypectomy site should be marked by means of sub- follows: R0 if all margins are clear, R1 if microscopic tumor is pres- mucosal injection and the precise level of the lesion recorded in ent at the margin, and R2 if gross disease is present. the procedure note. For the ﬁrst half of the 20th century, APR with permanent Benign-appearing sessile polyps of the rectum are generally colostomy was accepted as the treatment of choice for most rec- best removed in one piece by means of transanal local submucos- tal cancers. Improvements in perioperative care, anesthesia, and al or full-thickness operative excision rather than piecemeal by surgical technique; the development of reliable bowel-stapling means of endoscopic snare excision. This approach provides the devices; and improved understanding of the extent and nature of pathologist with a single specimen that can be properly oriented the spread of rectal cancer led to reductions in operative and can- for histologic examination to assess the depth of tissue invasion. It cer-related mortality and made anal sphincter–sparing operations also avoids the difﬁculties that arise when an unsuspected invasive increasingly reliable and popular. Gradually, anterior resection cancer is identiﬁed microscopically but inability to orient the mul- with colorectal anastomosis became the preferred procedure for tiple pieces of tissue removed by piecemeal excision precludes proximal rectal and midrectal cancers. accurate assessment of the T stage. Radical extirpation, with or without colorectal anastomosis, Snare polypectomy by itself is adequate for treating cancer aris- remained the only treatment option for most rectal cancers until ing in a rectal polyp if the lesion is noninvasive (i.e., conﬁned to the last quarter of the 20th century, when multimodality therapy the mucosa) or if an invasive cancer is conﬁned to the head, neck, was proved to be effective. Currently, surgeons frequently com- or stalk of a pedunculated polyp and the margins are clear. If bine chemoradiation with radical resection and increasingly per- tumor is present within 2 mm of the margin or if the cancer form restorative procedures even for distal rectal cancers. Despite extends into the submucosa of a pedunculated or sessile polyp, these improvements, local recurrence and poor function contin- additional therapy is usually indicated. Various options are avail- ue to be major sources of morbidity and mortality after radical able for such therapy, including transanal excision of the rectal resection. wall along with the base of the polyp (for accurate determination of the T stage), chemoradiation, and radical resection.The factors that determine whether local therapy is sufﬁcient for cancers aris- Local Procedures ing in a polyp or whether radical resection or adjuvant therapy is Local procedures used to treat rectal cancer include polypecto- indicated are reviewed elsewhere.37 my, excision, fulguration, and endocavitary radiation. Poly- pectomy and excision have the advantage of providing a biopsy Local Excision specimen that can be examined to determine the depth of tumor The goal of local excision procedures is to perform a full-thick- invasion and thereby conﬁrm or change the preoperative T stage. ness resection of the primary rectal cancer with a 1.0 cm margin. If microscopic examination of the specimen shows involvement of Local excision is most often accomplished via an endoanal the circumferential or deep margins or if the pathologic T stage is (transanal) approach under direct vision or by means of transanal more advanced than the preoperative clinical T stage, radical endoscopic microsurgery (TEM).The endoanal approach is gen- surgery or chemoradiation may be employed to improve local con- erally suitable for more distal tumors up to 10 cm from the anal trol. It is not clear whether this approach—excisional biopsy with verge, whereas TEM is appropriate for more proximal cancers. subsequent additional therapy depending on ﬁnal pathologic Posterior approaches to excision are rarely necessary. examination of the specimen—compromises survival in compari- Occasionally, it is helpful to expose the anorectum via a parasacral son with a more aggressive initial approach. Obviously, this incision so as to facilitate local excision of a rectal cancer that is approach is not feasible if local ablative techniques (e.g., endocav- otherwise difﬁcult to access. Currently, transsacral and transper- itary radiation or fulguration) are employed, because the primary ineal approaches are infrequently used because of the signiﬁcant lesion is destroyed and thus unavailable for pathologic study. associated morbidity (i.e., wound infections, bowel ﬁstulas, and Endocavitary radiation has the distinct advantage of being per- impaired continence).Tumors closer to the anal verge may involve formed in the outpatient setting with local anesthesia with seda- the anal sphincter; such involvement is a contraindication to local tion; however, it requires special equipment and expertise and is excision unless the patient is unﬁt for a more aggressive option. not widely available. Fulguration is now used primarily for pallia- tion. Its main advantage is that it controls bleeding from incurable Endoanal local excision Because of its relative simplicity rectal cancers with minimal morbidity. None of the local therapy and excellent safety record, transanal excision is the most com- techniques include removal of the mesorectum; thus, lymph monly performed local procedure [see Figure 1]. Full mechanical nodes are not assessed, and it is impossible for the pathologist to bowel preparation is recommended to reduce the possibility of conﬁrm or alter the preoperative N stage. postoperative impaction and to maintain optimal visualization. The procedure can be performed with the patient in either the OPERATIVE TECHNIQUE lithotomy or the prone jackknife position. The prone position has the advantages of providing easier access for an assistant surgeon Polypectomy and of being suitable for rectal cancers in any quadrant; the lithot- Snare polypectomy is most often done during colonoscopic omy position is most suitable for distal posterior tumors. The use examination of the entire colon with the assumption that the rec- of headlights or lighted retractors is highly recommended. A Lone tal polyp is benign. Polyps larger than 1.0 cm, polypoid villous Star self-retaining retractor or Gelpi retractors may be used to adenomas, and polyps with ﬁrm ulcerated areas are more likely to efface the anus, and a handheld bivalve retractor, a Ferguson-Hill
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 6 a b c Interrupted Lesion Excision Site Closure Figure 1 Local excision. (a) The rectal lesion is exposed with a bivalve retractor. (b) Full-thickness excision of the lesion is performed. (c) The defect is closed with interrupted sutures. retractor, or a Parks anoscope may be used to provide endoanal that such trials will ever be successfully completed. Studies involv- exposure of the lesion. Deep retractors (e.g., narrow Deaver ing short-term follow-up have not demonstrated any impact on retractors) are often helpful for exposing more proximal cancers. cancer-free survival for T1 cancers but have indicated that survival Dissection may be facilitated by injecting saline or a local anes- is compromised if T2 cancers are treated with local excision alone. thetic with epinephrine solution into the rectal wall near the More information is needed before deﬁnitive therapeutic recom- lesion. It is sometimes helpful to place a traction suture 2 cm dis- mendations can be made. tal to the lesion to facilitate prolapse of the rectal wall before dis- Local recurrence rates after local excision can be lowered by section is begun. An electrocautery with a needle tip is generally adding adjuvant radiation therapy, with or without chemotherapy. employed to perform a full-thickness excision of the cancer with Estimated local recurrence rates after adjuvant therapy range a 1.0 cm margin, but surgeons are increasingly using laparoscop- from 0% to 9% for T1 tumors and from 0% to 24% for T2 ic instruments to facilitate local excision. Hemostasis and orienta- tumors.39-41 Reliable long-term survival data are unavailable. To tion must be maintained. If desired, the defect in the rectal wall date, only three small retrospective series have evaluated a promis- may be closed as the dissection progresses. Each suture can be ing newer approach: neoadjuvant therapy followed by local exci- used for traction to keep the lesion in view. Innovative techniques sion of early-stage, favorable rectal cancers. Clinical trials aimed making use of laparoscopic or conventional staplers have also at studying this approach are being developed. been developed and have yielded good results. Once the specimen has been resected, it is inspected to conﬁrm Transanal endoscopic microsurgery TEM is a novel that adequate margins have been obtained, then marked for ori- technique that has found a niche in local treatment of sessile entation and pinned out for ﬁxation before histologic examina- polyps and of favorable T1 cancers in the middle to upper rectum. tion. The operative site may be irrigated with sterile water or It may be used in combination with chemoradiation to treat more tumoricidal agents to minimize the risk that viable tumor cells will advanced cancers of the middle and upper rectum, especially in be left in the rectal wall. If the rectal wall defect is extraperitoneal, high-risk patients who cannot tolerate an anterior resection. More it may be left open to heal secondarily; however, many prefer to proximal lesions of the rectum that are not amenable to transanal close all rectal wounds primarily.38 If the defect is intraperitoneal, excision or to endoscopic removal may be best treated by TEM, closure is essential and is usually performed with a durable with low morbidity and mortality. absorbable suture. Care must be taken to prevent stricture for- TEM begins with insufﬂation of CO2 into the rectum via a 4 mation.This is an especially critical concern if large or circumfer- cm operating rectoscope. Endoscopic instruments are then insert- ential lesions are removed. In such cases, a sleeve closure with a ed and used under magniﬁcation to perform the local resection. handsewn anastomosis after advancement of the proximal rectal The principles of resection are the same as for endoanal excision wall to the more distal rectum is often the best option. Once the (see above). defect is closed, the surgeon should perform proctoscopy to ensure that the rectal lumen has not been compromised. Results. The largest review of TEM results to date included 137 patients and reported an 8% minor morbidity rate, a 2% Results. The data currently available suggest that local recur- major morbidity rate, and a combined 5% recurrence rate for T1 rence rates are unacceptably high and that survival may be com- to T3 tumors over a period of 6 months.21 These results are promised even when curative-intent local therapy is restricted to promising, but the follow-up period is too short for deﬁnitive con- patients who have small, accessible intramural cancers with no clusions to be drawn. signs of suspicious lymph nodes on preoperative imaging studies and no unfavorable histologic features on the pretreatment biop- Posterior approach to local excision Local excision of sy.The risk of local recurrence after local excision of selected, pre- rectal cancers can be performed via either a transsacral or a sumably favorable lesions is 18% for T1 cancers and 37% to 47% transsphincteric approach with the patient in the prone jackknife for T2 cancers.27-32 Salvage surgery is often possible if follow-up position. The Kraske procedure takes a transsacral approach. An shows progression of pelvic cancer. No prospective studies direct- incision is made in the midline of the sacrum to expose the pos- ly comparing the results of local excision with those of more rad- terior rectum by excising the coccyx and the last two sacral verte- ical extirpative procedures have yet been done, and it is unlikely brae. Either a short segmental resection of the rectum with pri-
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 7 mary anastomosis or a proctotomy to expose and locally excise an of radical extirpative procedures. Headlights and lighted retrac- intraluminal lesion is performed. In closing the rectal wall defect, tors allow visualization deep in the pelvis. Self-retaining retractors care is taken not to compromise the lumen and create a stricture. (e.g., Balfour or Bookwalter retractors) are necessary. The St. The York-Mason procedure takes a transsphincteric approach Mark pelvic retractor and the Wylie renal vein retractor facilitate to expose the posterior rectum without resection of the sacrum. deep pelvic dissection. Long instruments are essential, and a vari- Instead, the pelvic ﬂoor muscles are divided in the posterior plane, ety of staplers should be available.The presence of an experienced and the resection then proceeds as in the Kraske procedure. The second surgeon or a highly trained assistant is invaluable. sphincter muscles must be carefully reconstructed. Unfortunately, morbidity is relatively high (e.g., a 20% incidence of fecal ﬁstula) Intraoperative Decision Making after both procedures.42 The surgeon always has a plan in place for the operation before laparotomy, but it often happens that intraoperative ﬁndings Fulguration (Electrocoagulation) necessitate a change in the plan. Thus, the surgeon must be ﬂexi- Fulguration, or electrocoagulation, involves destroying a cancer ble and willing to alter the planned operation in accordance with with an electrode inserted into the wall of the lesion. As coagulum the situation. builds up, it is debrided to allow additional coagulation until the After a midline incision is made, a thorough abdominal explo- lesion and a circumferential rim of normal tissue have been ablat- ration is performed. At this point, the surgeon can conﬁrm or ed. The disadvantages of this procedure include postoperative revise the operative plan. Most often, the choice between a sphinc- fever, the lack of a surgical specimen for staging, the requirement ter-sparing approach and a sphincter-sacriﬁcing approach has for repeated procedures, and the need to convert to more radical been made before operation, but for distal rectal cancer, it is not procedures in a large number of patients.43 always possible to determine whether a restorative anastomosis is Fulguration has often been used as curative-intent treatment, feasible until the rectum has been fully mobilized. In such cases, with reported 5-year survival rates reaching 58%, but it is now the choice between sphincter-sparing and sphincter-sacriﬁcing used primarily for palliative purposes. Fulguration may be optimal proctectomy must be based on assessment of the adequacy of the for patients with bulky bleeding rectal cancers who are too ill to distal margin [see Anterior Resection, Operative Technique, Step undergo radical resection. 4, below]. Neoadjuvant therapy can reduce the size of a tumor so that it Endocavitary Radiation (Papillon Technique) is amenable to low anterior resection instead of requiring APR.45 Endocavitary radiation involves high-dose contact (superﬁcial) After full rectal mobilization, the surgeon assesses the possibility radiotherapy delivered via a specially designed proctoscope. A of obtaining clean radial and distal margins, then decides to pro- total radiation dose of 9 to 15 Gy is delivered in several sessions, ceed with either resection and anastomosis or APR.The desire to usually over a period of 60 days. This modality is appropriate for perform an anastomosis must not be allowed to compromise small noncircumferential lesions located within 10 cm of the anal oncologic outcome. Occasionally, circumstances arise in which verge.The reported 5-year survival rate is 76%, with a local recur- the cancer is larger than anticipated or is extending into the rence rate of 8.3% and a mortality of 7.7%.44 sacrum or other pelvic structures. In such circumstances, a more extensive operation than was originally planned is appropriate if curative resection can be achieved. Alternatively, the surgeon may Radical Procedures be forced to perform a palliative operation. OPERATIVE PLANNING ANTERIOR RESECTION Preoperative Preparation Operative Technique The possibility that a permanent or temporary stoma may be All curative-intent radical resections for rectal cancer use the necessary should prompt a consultation with an enterostomal same technique for mobilizing the rectum and achieving proxi- therapy nurse for the purpose of counseling the patient and mark- mal, lateral, and radial margin clearance. Anterior resections are ing the abdominal wall at the appropriate location for a colosto- classiﬁed as high, low, or extended low, depending on the extent my or temporary ileostomy [see 5:30 Intestinal Stomas]. of rectal mobilization and resection and on the level of the restora- Generally, full mechanical and antibiotic bowel preparation is tive anastomosis. performed on an outpatient basis the day before operation. An antibiotic is administered intravenously just before induction of Step 1: mobilization of colon After abdominal exploration, anesthesia. General anesthesia is employed, and an epidural the small bowel is packed into the upper abdomen, and the catheter is often inserted to provide postoperative analgesia. If patient is placed in a slight Trendelenburg position. The rectosig- there is a large, bulky rectal tumor or an associated inﬂammatory moid is retracted to the right, and the peritoneal attachments to mass, ureteral stents may be placed to facilitate intraoperative the left of the sigmoid colon are incised along the avascular plane. identiﬁcation and protection of the ureters. A bladder catheter is The left ureter and gonadal vessels are identiﬁed and preserved by inserted, and the patient is placed in a modiﬁed lithotomy posi- using sharp and gentle blunt dissection to separate the retroperi- tion with the legs in stirrups. Pneumatic compression stockings toneal tissues from the sigmoid mesentery. The peritoneum is and compression devices are used routinely, with or without incised along the left side of the descending colon as far as the heparin. Digital rectal examination and rigid proctoscopy are per- splenic ﬂexure. Adhesions to the spleen are divided, and the formed to empty the rectum and reassess the rectal cancer. The splenic ﬂexure is taken down. The colon mobilization extends degree of involvement of the anal sphincter or other organs, the proximally to the left transverse colon. level of the distal edge of the tumor, and the response of the tumor to chemoradiation are noted. Step 2: ligation of inferior mesenteric artery The mobi- A number of instruments are required to facilitate the conduct lized rectosigmoid is retracted anteriorly and to the left to expose
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 8 During the retrorectal dissection, the hypogastric nerves are identiﬁed at the sacral promontory. These nerves descend in the presacral space in a wishbone shape and must be preserved to maintain postoperative sexual and urinary function. In the 1940s, sexual dysfunction after proctectomy was reported in 95% of male patients.46 If attention is given to nerve preservation during proctectomy, however, 86% of male patients younger than 60 years retain sexual function.47 Posteriorly, the rectosacral fascia is divided under direct vision, and the dissection proceeds distally to the level of the coccyx. In mobilizing the rectum, it is helpful to 2 dissect in a posterior-to-lateral direction, with care taken to main- tain the integrity of the endopelvic fascial envelope encasing the 1 bilobed mesorectum. The nervi erigentes are identiﬁed and pre- served on the lateral pelvic sidewalls. When the middle rectal artery is present as a distinct vessel, it can generally be fulgurated during the lateral dissection; occasionally, however, the vessel is large enough that ligation is necessary. The ﬁnal attachments are divided anterolaterally, and the ante- rior pelvis is exposed. Exposure may be facilitated by reducing the angle of the Trendelenburg position or even shifting the patient to a reverse Trendelenburg position. The cul-de-sac is opened, and Denonvillier’s fascia is incised. Deep pelvic retractors are placed to protect the seminal vesicles and prostate (in males) or the vagi- na (in females) as the dissection continues distally. Step 4: assessment of distal margin At this point in the operation, the rectum has been fully mobilized via the abdominal approach, and the surgeon must decide whether a sphincter-pre- serving anastomosis is possible or whether a sphincter-sacriﬁcing resection with construction of a permanent colostomy is neces- sary. Because all radical resections for rectal cancer use the same proximal, lateral, and radial dissection technique, the decision to perform an anastomosis is based primarily on the ability to obtain a clear distal margin. There are two components to the distal margin: intramural and mesorectal. At one time, a 5.0 cm intramural margin was recom- Figure 2 Anterior resection. Illustrated is the tissue excised dur- mended; however, subsequent studies demonstrated that a 2.0 cm ing anterior resection. The surgeon may perform either a low li- gation of the IMA (1), with preservation of the ascending branch, intramural margin was adequate for curative resection. Margins or a high ligation (2), where the IMA branches from the aorta. smaller than 1.0 cm were associated with increased local recur- rence rates and decreased survival.48-50 Considerable emphasis is now being placed on ensuring adequate mesorectal clearance. It the inferior mesenteric artery (IMA). Transillumination of the was observed that local recurrence after radical resection correlat- mesentery facilitates identiﬁcation of an avascular space adjacent ed not just with the stage of the disease but also with the surgeon to the IMA at the base of the mesentery. The peritoneum overly- performing the operation. Careful analysis suggested that some ing this space is incised on either side of the IMA. Some surgeons surgeons did not remove the mesorectum completely and that prefer a high ligation of the IMA where it branches from the aorta, tumor deposits in the mesorectum distal to the rectal cancer were suggesting that this measure provides a more complete lymph responsible for high recurrence rates.51 Total mesorectal excision node harvest. Others prefer a low ligation of the IMA just distal to (TME) was recommended as a means of minimizing local recur- the left colic artery, suggesting that this approach ensures better rences. The current view is that a 5.0 cm mesorectal clearance is blood supply to the proximal colon and prevents nerve injury at essential to prevent local recurrence in the pelvis. the base of the IMA [see Figure 2]. At present, there is not enough If distal clearance (both intramural and mesorectal) is adequate evidence to recommend one approach over the other. After liga- and if anal sphincter function justiﬁes proceeding with an anasto- tion of the IMA, it is convenient to divide the colon at the mosis, a right-angle clamp is placed distal to the tumor, and the descending-sigmoid junction with a linear stapler. distal rectum is irrigated with sterile water or a tumoricidal agent. A second right-angle clamp is then placed distally, and the rectum Step 3: total mesorectal excision and preservation of is divided between the two clamps. This technique is used if an autonomic nerves The rectosigmoid is retracted anteriorly open purse-string suture is to be placed in the distal rectal cuff. If and inferiorly toward the pubis to expose the avascular plane pos- a double-stapled reconstruction is planned instead, a transverse terior to the rectum. Sharp incision of this avascular plane while anastomosis (TA) stapler is placed distal to the right-angle clamp. traction is placed on the rectosigmoid typically allows air to enter The stapler is ﬁred and the rectum divided, leaving a closed rec- the areolar tissue posterior and lateral to the rectum.The surgeon tal cuff for subsequent anastomosis. follows the air, sharply dividing the loose areolar tissue posterior- The surgeon should then examine the resected specimen to ly and laterally [see Figure 3]. assess the radial and distal margins and evaluate the integrity of
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 9 the mesorectal dissection. If the margins are inadequate or the stapler, without the anvil but with a trocar attachment, is inserted mesorectum has been violated, local recurrence is a major con- through the anus and advanced proximally to the apex of the cern.The treatment plan may have to be altered to reduce the risk closed stump [see Figure 4b].The stapler is opened to drive the tro- of recurrence. car through the apex of the rectal stump adjacent to the staple line. The trocar attachment is removed, and the mobilized Step 5: creation of anastomosis Several reconstructive descending colon, with the anvil in place, is mated to the stapler options are available for restoring bowel continuity after radical [see Figure 4c].The stapler is closed and ﬁred, resulting in an end- proctectomy. An end-to-end anastomosis is the traditional choice, to-end anastomosis [see Figure 4d].The integrity of the anastomo- but alternative anastomoses are acceptable options in some situa- sis is assessed by insufﬂating air into the rectum with a procto- tions [see Alternative Anastomoses, below]. scope while the anastomosis is under water [see Figure 5]. A straight or an end-to-side colorectal anastomosis (the Baker technique) is appropriate after resection of most cancers in the Purse-string end-to-end anastomosis. The alternative to the dou- proximal half of the rectum. The anastomosis can be handsewn, ble-stapled technique is to place purse-string sutures on both the but most surgeons prefer to use a circular stapler. Functional proximal and the distal end of the bowel to be anastomosed. A results after such proximal anastomoses are generally good. As continuous 2-0 purse-string suture is placed in the proximal end surgeons developed reliable means of performing lower colorectal of the open rectal cuff, and a second purse-string suture is placed and coloanal anastomoses, functional results were often subopti- in the descending colon [see Figure 6]. The circular stapler is mal: patients reported urgency, frequency, seepage, and inconti- placed through the anus, and the anastomosis is fashioned and nence.To overcome these problems, surgeons devised newer tech- checked for leaks as in the double-stapled technique. niques aimed at increasing rectal reservoir capacity (e.g., the colonic J pouch and coloplasty). Handsewn end-to-end anastomosis. The alternative to a stapled anastomosis is a handsewn colorectal end-to-end anastomosis, Double-stapled end-to-end anastomosis. The double-stapled which may be done in one or two layers with interrupted or con- technique was devised to eliminate the need for a purse-string tinuous sutures. Handsewn colorectal anastomoses are typically suture on the rectal cuff and to prevent fecal contamination. A performed from the abdominal ﬁeld. It is often easiest to place all purse-string suture is placed in the cut edge of the distal descend- of the sutures ﬁrst, then “parachute” the proximal bowel down to ing colon [see Figure 4a]. The anvil of a circular stapler is inserted the rectal cuff as the sutures are tied. The knots are generally tied into the descending colon, and the purse-string is tied. on the inside to produce mucosal inversion. The integrity of the stapled distal rectal stump is checked by Alternatively, if the distal cuff cannot be visualized from the insufﬂating air into the rectum via a proctoscope while the rectal abdominal ﬁeld, a handsewn anastomosis may be performed stump is covered with saline. If no air leaks are noted, the circular transanally. This is generally more easily accomplished with the patient in the prone jackknife position. Alternative anastomoses. Three alternative reconstruction pro- cedures have been devised to facilitate restoration of bowel conti- Prostate nuity deep in the pelvis.The colonic J pouch and the Baker tech- nique involve an end-to-side anastomosis, an approach that some surgeons believe offers a more reliable blood supply than the tra- Vesicle ditional end-to-end anastomosis. The colonic J pouch and colo- plasty were designed to overcome the poor functional outcomes frequently observed after straight coloanal or low colorectal anas- Neurovascular tomoses by increasing the capacity of the neorectum. Bundle A colonic J pouch is considered only for low anastomoses less than 5 cm from the anal verge; if the procedure is performed more proximally than 8 cm from the anal verge, it offers no functional advantages over a straight colorectal anastomosis.52 Patients with a colonic J pouch anastomosis 4 cm or less from the anal verge demonstrate the greatest functional improvements.52 To create a colonic J pouch, the splenic ﬂexure is mobilized to provide adequate bowel length, and a well-vascularized segment of the colon is selected for the pouch.The distal descending colon is then folded into a J conﬁguration [see Figure 7a]. It is essential that the hook (i.e., the efferent limb) of the J be no longer than 5 to 6 cm, because longer limb lengths are associated with difﬁcul- ty in evacuation.53 A linear cutting stapler is inserted through a colotomy on the antimesenteric surface of the inferior aspect of the J pouch, then closed and ﬁred. Once the linear staple line has been checked for bleeding, the anvil of a circular stapler is placed in the colotomy of the J pouch and secured in place with a 2-0 nonabsorbable suture.The J pouch–anal anastomosis is then per- Figure 3 Anterior resection. Shown is a schematic depiction of formed with the circular stapler [see Figure 7b]. total mesorectal excision, highlighting the endopelvic fascial dis- Approximately 25% of patients are not suitable candidates for section plane. a colonic J pouch because of a narrow pelvis or obesity.54 For
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 10 a b c d Figure 4 Anterior resection. Shown is a double-stapled end-to-end anastomosis. (a) The rectal stump is closed with a linear noncutting stapler. A purse-string suture is placed around the colotomy, and the anvil of the circular stapler is placed in the open end and secured. (b) The stapler, with the sharp trocar attachment in place, is inserted into the anus, and the trocar is made to pierce the rectal stump at or near the staple line, after which the trocar is removed. (c) The anvil in the proximal colon is joined with the stapler in the rectal stump, and the two edges are slowly brought together. (d) The stapler is ﬁred and then gently withdrawn. these patients, coloplasty is an alternative. Coloplasty is similar resection, the stapler anvil is inserted through the cut end of the to Heineke-Mikulicz pyloroplasty. An 8 to 10 cm long antimes- descending colon. The trocar end of the anvil is brought out enteric colotomy is initiated at a point 5 to 6 cm from the cut through the antimesenteric side of the colon approximately 3 to 4 end of the descending colon and extended proximally [see Figure cm from the distal cut end.The open end of the descending colon 8a]. The anvil of a circular stapler is placed in the colon and is closed. A circular stapler is then used to anastomose the side of brought out the end of the colon before closure of the coloplas- the colon to the end of the rectum or the anal canal [see Figure 9]. ty. The colotomy is closed in a transverse direction, perpendicu- lar to the antimesenteric border, with either absorbable sutures Troubleshooting or a linear stapler [see Figures 8b and 8c]. An end-to-end anasto- Criteria for temporary fecal diversion The incidence of mosis is then performed with the circular stapler [see Figure 8d]. anastomotic complications, including leakage, correlates with the This procedure has not been accepted by most surgeons because level of the anastomosis: in general, the lower the anastomosis, the of the long longitudinal colotomy along the antimesenteric higher the complication rate. Other factors, including previous border. radiation therapy, immunosuppression, and underlying vascular Although the end-to-side (Baker) anastomosis is not a new insufﬁciency or diabetes, may also increase the risk of anastomot- technique, it is gaining popularity as an alternative to the more ic complications. difﬁcult and time-consuming pouch procedures. After the rectal The consequences of a leaking anastomosis remain a major
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 11 Figure 5 Anterior resection. The integrity of the anastomosis is assessed by holding it under water and insufﬂating air via a proctoscope while the bowel is clamped. source of morbidity and death after surgical resection of rectal ty of life after coloanal or colorectal reconstruction.The data indi- cancer. Consequently, many surgeons perform routine temporary cate that the functional advantages of coloplasty and colonic J fecal diversion for patients undergoing low anastomoses, especial- pouches are most discernible in the ﬁrst 2 years after operation. ly for those subjected to preoperative irradiation or receiving Measures of function—including urgency, frequency, nocturnal steroid treatment. Loop ileostomy is the most commonly per- stooling, and continence—all show signiﬁcant improvements in formed temporary diversion, though some surgeons prefer proxi- patients who undergo colonic J pouch or coloplasty reconstruc- mal loop colostomy [see 5:30 Intestinal Stomas]. Proximal fecal tion56; quality-of-life indicators and physiologic measures show diversion does not protect against anastomotic leakage or prevent signiﬁcant improvements as well.57 A 2002 trial from Singapore anastomotic complications, but it does diminish the morbidity found the incidence of anastomotic leaks to be higher after colo- resulting from leakage and reduce the likelihood of an emergency plasty reconstruction than after colonic J pouch reconstruction.58 operation.55 Our practice is to perform diversion for all patients Although this ﬁnding has tempered the enthusiasm for coloplasty with a colorectal or coloanal anastomosis within 5 cm of the anus, reconstruction, the procedure remains a viable option in the especially if they have undergone preoperative radiation therapy or patient with a narrow pelvis. are immunosuppressed. The functional and surgical results seen with end-to-side anas- tomoses are similar to those seen with colonic pouch anasto- Outcome Evaluation moses.59 More data are needed to determine which reconstructive Information is now available on functional outcome and quali- technique is best in which setting. a b Figure 6 Anterior resection. Shown is a purse-string end-to-end anastomosis. (a) Purse-string sutures are placed on the rectum and on the proximal bowel. (b) The anvil of a circular stapler is placed in the proximal bowel, and the stapler is placed through the anus. The anvil is joined with the body of the stapler, and the stapler is ﬁred to complete the anastomosis.
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 12 a more restorative anastomoses after radical resection of rectal can- cer are based on data suggesting that APR offers no survival advantage over sphincter-sparing procedures.17 Nevertheless, APR is still performed in an estimated 30% to 60% of rectal cancer b patients. A large review of 7,400 patients in the United States doc- umented a 58% rate of APR performance.60 The reasons for this persistently high APR rate are unclear. Operative Planning Synchronous APR APR, as the name suggests, may be thought of as comprising two phases: an abdominal phase and a perineal phase. The perineal phase of the operation may be done synchronously with the abdominal phase, with the patient main- tained in a modiﬁed lithotomy position. Proper positioning and exposure are critical. The buttocks should be elevated with a pad extending over the edge of the operating table and should be taped laterally to provide good exposure of the perineum. The synchro- nous approach may reduce operating time and is useful if the sur- geon anticipates any difﬁculty in removing the rectum because of lateral ﬁxation.Working from above and below the area of ﬁxation simultaneously usually allows the proctectomy to be safely com- pleted en bloc.This approach demands the presence of two expe- rienced surgeons: performing the perineal phase with the patient in the lithotomy position can be very demanding technically, espe- cially if the patient is obese. Figure 7 Anterior resection. Shown is the creation of a coloanal anastomosis with a colonic J pouch. (a) The proximal bowel is sta- Sequential APR Alternatively, the perineal phase may be per- pled closed and folded into a J shape, with the hook of the J being formed with the patient in the prone jackknife position after com- about 5 to 6 cm long. A colotomy is made in the base of the J, and a J pouch is formed by inserting and ﬁring a linear stapler. The pletion of the abdominal phase.This approach is generally preferred anvil of a circular stapler is placed in the base of the pouch. (b) because it provides excellent visualization for the perineal dissection The J pouch is brought down to the anus, and the circular stapler and is especially useful if the tumor is ﬁxed anteriorly. In addition, is used to create the coloanal anastomosis. it has the advantage of providing more room for an assistant. Operative Technique ABDOMINOPERINEAL RESECTION Steps 1 through 4 The abdominal phase of APR, including APR involves en bloc resection of the rectosigmoid, the rectum, TME and nerve preservation, is identical to steps 1 through 4 of and the anus along with the surrounding mesentery, mesorectum, an anterior resection [see Anterior Resection, Operative and perianal soft tissues [see Figure 10]. Current efforts to perform Technique, above]. a b c d Figure 8 Anterior resection. Illustrated is the coloplasty technique. (a) A longitudinal colotomy is made in the antimesenteric side of the colon. (b) Sutures are placed on either side of the incision and used to apply traction transversely. (c) The colotomy is closed in a transverse direction. (d) An end-to-end anastomosis to the anus is performed.
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 13 is completed anteriorly, the specimen is inspected and sent for pathologic examination. The pelvis is irrigated and hemostasis secured. Some surgeons prefer to place a mobilized pedicle of omentum into the pelvis to facilitate healing and reduce the risk of small-bowel adhesions in the depths of the pelvis. The perineal incision is closed in several layers with absorbable sutures. A trans- abdominal drain is placed in the pelvis. Step 6: creation of colostomy An end colostomy [see 5:30 Intestinal Stomas] is created before the perineal dissection if sequential APR is performed but may be created simultaneously with the perineal resection if a two-team synchronous APR is performed. A 2 cm circular incision is made in the skin and sub- cutaneous tissues overlying the premarked stoma site, which is usually in the left lower quadrant of the abdomen. A cruciate incision is made in the anterior fascia, the rectus abdominis is split, and a second cruciate incision is made in the posterior fas- cia. The mobilized colon is passed through this site and ﬁxed to the skin with 3-0 or 4-0 absorbable sutures. Because many enterostomal therapists and patients ﬁnd it easier to pouch an elevated left-side colostomy, an eversion technique is used to mature the stoma. Figure 9 Anterior resection. Depicted is a double-stapled end- to-side colorectal anastomosis. Step 5: perineal resection The perineal phase of APR is performed with the patient in either the lithotomy or the prone jackknife position, depending on whether the synchronous or the sequential approach is followed.The perineum is exposed with the aid of self-retaining retractors [see Figure 11]. The anus is closed with a heavy purse-string suture to minimize the risk of spillage of feces or tumor. An alternative means of accomplishing this goal is to make the initial elliptical incision around the anus and then approximate the perianal skin edges with sutures or Kocher clamps. The elliptical incision should extend from the perineal body anteriorly to the coccyx posteriorly. Laterally, the incision should overlie the ischium. The incision is deepened into the ischioanal fossa bilaterally with the electrocautery. The anococ- cygeal ligament is divided posteriorly. The perineal surgeon can then insert an index ﬁnger into the pelvis to guide division of pos- terolateral soft tissue with the electrocautery. An appendectomy retractor or springs may be used to improve retraction during deeper dissection into the perineum. The dissection is continued laterally and anterolaterally. When an ample aperture is created, the proximal end of the specimen is passed between the coccyx and the anus. Traction is applied to the everted specimen to help the surgeon develop the anterior dissection plane. In a female patient, an ante- rior lesion may necessitate a posterior-wall vaginectomy to ensure adequate margins. In a male patient, anterior dissection may lead to injury to the urethra or excessive bleeding from the prostate capsule; to minimize the risk of the former, it is helpful to palpate Figure 10 Abdominoperineal resection. Illustrated is the tissue the Foley catheter during anterior dissection. Once the dissection excised during APR.
© 2004 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 5 Gastrointestinal Tract and Abdomen 35 Procedures for Rectal Cancer — 14 a b c d e Figure 11 Abdominoperineal resec- tion. Shown is the perineal phase of APR. (a) An elliptical incision is made around the anus. (b) Springs or retrac- tors are used to provide exposure. (c) Mobilization continues up to the trans- versus perinei superﬁcialis. (d) The le- vator muscles are divided posteriorly. (e) The specimen is delivered through the wound posteriorly, and the anterior dissection is complete. OTHER RADICAL PROCEDURES traindication to sacrectomy because in this setting, the procedure would result in unacceptably high morbidity and functional Hartmann Procedure sequelae. In the setting of advanced disease, the surgeon should The Hartmann procedure [see 5:32 Procedures for Diverticular consider comfort care or additional adjuvant therapy before per- Disease] is a seldom-used option that plays only a limited role in forming palliative exenteration. Other treatment modalities (e.g., the treatment of rectal cancer. It may be a good choice if the like- intraoperative radiotherapy, brachytherapy, and further chemora- lihood of local recurrence is high (as with a perforated cancer) or diation) may be useful in this population. if the patient manifests preexisting sphincter dysfunction. In these situations, perineal dissection subjects the patient to unnecessary morbidity. The distal rectum or anal canal is stapled closed and Outcome Evaluation left in situ in the pelvis. The end colostomy is performed as in APR. FOLLOW-UP REGIMENS The primary purpose of surveillance after treatment of rectal Pelvic Exenteration and Sacrectomy cancer is to detect early recurrence so that salvage therapy can be The indications for pelvic exenteration are limited by the rela- instituted. A secondary purpose is to prevent development of a tively high morbidity and mortality associated with the procedure. metachronous cancer by identifying and removing new polyps. Pelvic exenteration for locally advanced or recurrent rectal cancer Symptoms of pain, pressure, weight loss, or bowel dysfunction has been shown to have oncologic and palliative beneﬁts. should be investigated. In addition to the physical examination, Reported 5-year survival rates after pelvic exenteration for locally various laboratory studies, endoscopic procedures, and imaging recurrent rectal cancer range from 20% to 30%.61 Primary modalities are used to detect or exclude recurrences. Although advanced rectal cancer, however, is less often amenable to pelvic survival is improved after resection of recurrent lesions, especially exenteration. in the setting of hepatic metastases, few data exist on the utility of Pelvic exenteration may involve resection of the anus, the rec- close follow-up. Some studies have questioned the utility of fol- tum, the bladder, the ureters, and the pelvic reproductive organs. low-up protocols.63,64 A survey of the American Society of Colon Sacrectomy is sometimes necessary as well if the rectal cancer is and Rectal Surgeons and the Society of Surgical Oncology found invading posteriorly.62 Reconstruction after these procedures that practice patterns were highly variable and that there was no involves both fecal and urinary diversion; consequently, a multi- clear consensus on what constitutes appropriate follow-up after disciplinary team is usually needed. treatment of rectal cancer.65 Detailed preoperative and intraoperative examination is essen- Most follow-up regimens include a routine history and physi- tial to verify the presence of localized resectable disease before cal examination, carcinoembryonic antigen (CEA) testing, CT proceeding with exenteration. If there is evidence of carcinomato- scanning, and routine colonoscopic evaluation.The roles of MRI, sis, liver metastases, pelvic sidewall invasion, bilateral ureteral PET, and other imaging studies have not been deﬁned. Our prac- obstruction, or aortic node metastases, curative exenteration can- tice is to follow good-risk rectal cancer patients who have under- not be performed. Invasion of the upper sacral vertebra is a con- gone curative-intent therapy every 4 months with ERUS and rigid
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