Carcinoma rectum has several risk factors including family history, inflammatory bowel disease, and genetic conditions. The rectum is divided into three portions with different lymphatic drainage patterns and implications for surgery. Staging includes Dukes', Astler-Coller, TNM, and clinical features are important for diagnosis. Treatment depends on stage and may include transanal excision, chemoradiation, surgery such as anterior resection or APR, and adjuvant therapy.

1. Carcinoma rectum Dr. vinayak lokare JMMC & RI

3. Etiology average lifetime risk - 6% risk increases two- to fourfold history of or a first-degree relative with colorectal cancer. Inflammatory bowel disease (IBD) Genetics – familial adenomatous polyposis (FAP) - APC gene on chromosome 5q21 hereditary nonpolyposis colorectal cancer (HNPCC)

4. Anatomy divided into three portions lower rectum -3 to 6 cm from the anal verge midrectum - 5 to 6 to 8 to 10 cm upper rectum - 8 to 10 to 12 to 15 cm determination of the location of the boundary between rectum and sigmoid colon is important in defining adjuvant therapy

5. anatomy upper extent of the rectum can be identified where the tenia spread to form a longitudinal coat of muscle The distance from the anal sphincter musculature is clinically of more importance than the distance from the anal verge, as it has implications for the ability to perform sphincter-sparing surgery

7. Lymphatic drainage Upper rectum - follows the course of the superior hemorrhoidal artery toward the inferior mesenteric artery Middle rectum - follow the middle hemorrhoidal artery lesions occur below the dentate line, the lymphatic drainage is via the inguinal nodes and external iliac chain

8. Types Macroscopic Proliferative Ulcerative Tubular Microscopic Adenocarcinoma Colloid carcinoma Squamous cell carcinoma

9. Clinical features Bleeding per rectum – mucous +/- Alteration of bowel habits – increasing constipation, early morning diarrhoea Sense of incomplete defeacation Intestinal obstruction Pain Loss of appetite ,weight loss , joundice , ascitis

10. Investigations USG abdomen Proctosigmoidoscopy / biopsy Colonoscopy contrast CT of the pelvis and the abdomen Endoscopic USG

11. Chest X-ray Liver function tests Renal function tests Baseline CEA levels

12. staging Dukes’ staging A- limited to bowel wall B-spread outside the bowel wall C-involvement of lymph nodes Astler- Coller modification B1-infiltration into muscularis propria B2- infiltration beyond muscularis propria into serosa

13. C1- lymph node involvement but did not penetrate the entire bowel wall C2- tumors that invaded lymph nodes and did penetrate the entire wall (C2).

14. TNM staging TX- Primary tumor cannot be assessed T0 - No evidence of primary tumor Tis - Carcinoma in situ: intraepithelial or invasion of lamina propria [*] T1 - Tumor invades submucosa T2 - Tumor invades muscularis propria T3- Tumor invades through the muscularis propria into the subserosa, or into nonperitonealized pericolic or perirectal tissues T4 Tumor directly invades other organs or structures and/or perforates visceral peritoneum [†]

15. NX- Regional lymph nodes cannot be assessed N0- No regional lymph node metastasis N1 - Metastasis in 1 to 3 regional lymph nodes N2- Metastasis in 4 or more regional lymph nodes

16. MX Distant metastasis cannot be assessed M0 - No distant metastasis M1 - Distant metastasis

17. STAGE T N M DUKES [§] MAC [§] 0 Tis N0 M0 I T1 N0 M0 A A T2 N0 M0 A B1 IIA T3 N0 M0 B B2 IIB T4 N0 M0 B B3 IIIA T1-T2 N1 M0 C C1 IIIB T3-T4 N1 M0 C C2 IIIC Any T N2 M0 C C1/C2 IV Any T Any N M1 D

18. Treatment Stage 1 TEM EUS- T1, T2 <40% circumference involvement Well- mod. Differentiated HPR – no lymphatic / venous invasion

19. posterior proctotomy- Kraske procedure large posterior lesions allows for the mobilization of the rectum and a full-thickness local excision T2 lesions- Adjuvant chemoradiation

20. Endocavitary radiation therapy T1 or T2 tumors less than 3 cm, not poorly differentiated, with no evidence of nodal involvement four rounds of 2,500 to 3,000 cGy each with 2 to 3 weeks between treatments

21. Stage 2 and stage 3 Preoperative Chemo therapy – 5-FU(350mg/m2/day) for 5 days Leucovorin(20mg/m2) for 5 days 2cycles Radiotherapy 5000cGy Surgery after 4-6 wks

22. Surgery Upper rectum – anterior resection Middle rectum – low anterior resection Low rectum - low anterior resection / APR Adjuvant chemotherapy 5-FU + leucovorin – 4 cycles

23. Stage 4 Preoperative chemo radiation APR Post operative chemo / RT

24. radiotherapy Proximal – sacral prmontary Distal – 2 cm below primary tumor mass Lateral – pelvic wall Posterior – sacrum Anterior – posterior border of vagina / prostate

25. 5-FU based adjuvant chemotherapy has been the standard of care for advanced rectal cancer 5-FU treats micrometastases – 5-FU acts as a radiosensitizer Continuous infusion has shown improved survival and increased time to relapse when compared to bolus therapy