1) Colorectal cancer is one of the most common malignancies and symptoms often do not appear until late stages. Common symptoms include abdominal pain, rectal bleeding, and changes in bowel habits. 2) Diagnosis involves blood tests like CEA levels, fecal occult blood testing, imaging like colonoscopy, CT, and MRI to detect cancer and stage it. Colonoscopy allows visualization of lesions and biopsy but has risks. 3) Colon cancer risk increases with age and family history. Screening is recommended regularly for average risk individuals to detect early-stage cancers when treatment is most effective.

1. SHER-I-KASHMIR INSTITUTE OF MEDICAL
SCIENCES
CLINICAL FEATURES AND INVESTIGATIONS
IN
CARCINOMA COLON
PREPARED BY
DR IFRAH AHMAD QAZI

2. INTRODUCTION
 Most common malignancy in gastrointestinal tract
 More common in females
 Age related increase in incidence ( mean age ~ 70-75 years)
(1) Maingot’s Abdominal Operation ; 12th edition; Section V ; Chapter 36 , p

3. CLINICAL FEATURES

4. SYMPTOMS
 Absent until late stage
 Subtle and vague
 Abdominal pain
 Rectal bleed
 Recent change in bowel habits
 Involuntary weight loss
Falterman KW, Hill CB, Markey JC, Fox JW, Cohn I Jr. Cancer of the colon, rectum, and
anus: a review of 2313 cases. Cancer 1974;34:951–9

5.  Less common symptoms
 Nausea and vomiting
 Malaise
 Anorexia
 Abdominal distention

6.  Symptoms depend upon :
 Cancer location
 Cancer size
 Presence of metastasis
Posner MC, Steele GD Jr, Mayer RJ. Adenocarcinoma of the colon and rectum. In: Zuidema GD, editor. Shackelford’s surgery of the alimentary
tract. 5th edition. Philadelphia: WB Saunders; 2002. p. 219–36

7.  Left colon cancer :
 Constrictive in nature
 Cause partial or complete obstruction as lumen narrower
and stools better formed
 Partial obstruction can sometimes produce paradoxical
diarrhoea
 More distal cancers produce gross rectal bleed

8.  Right colon cancer :
 Causes occult blood loss or melena
 Iron deficiency anaemia and symptoms associated with it
 Distal ileal obstruction
 Advanced cancer causes cancer cachexia
 Involuntary weight loss
 Anorexia
 Muscle weakness
 Feeling of poor health
 Cappell MS. Colon cancer during pregnancy: the gastroenterologist’s perspective. Gastroenterol Clin North Am 1998;27:225–56.
 Harewood GC, Ahlquist DA. Fecal occult blood testing for iron deficiency: a reappraisal. Dig Dis 2000;18:75–82.
 Theologides A. Cancer cachexia. Cancer 1979;43:2004–12

9. SIGNS
 Signs tend to present in advanced stages
 Signs related to anaemia :
 Pallor
 Koilonychia
 Cheilitis
 Glossitis
 Signs of hypoalbuminemia
 Peripheral oedema
 Ascitis
 Anasarca
 Hypoactive or high pitched bowel sounds suggesting
obstruction
 Palpable abdominal mass
 Rectal cancer may be palpable on digital rectal exam

10. DIAGNOSIS

11. RISK STRATIFICATION
Risk factors
• Past history of colorectal cancer, pre-existing adenoma,
ulcerative colitis, radiation
• Family history – 1st degree relative < 55 yo and relatives with
identified genetic predisposition (e.g. FAP, HNPCC, Peutz-
Jegher’s syndrome) = more risk
• Diet – carcinogenic foods

12. Risk category (for asymptomatic pts)
• Category 1 (2x risk) – 1o or 2o relative with colorectal cancer
>55 yo
• Category 2 (3~6x) – 1o relative < 55yo or 2 of 1o or 2o relative
at any age
• Category 3 (1 in 2) – HNPCC, FAP, other mutations identified

13. SCREENING

14. INVESTIGATIONS
 Routine biochemical tests :
 Haemogram
 Serum electrolytes
 Blood glucose
 Liver function tests
 Coagulation profile
 Anaemia of undetermined etiology warrants evaluation for colon ca
 Vomitting and diarrhoea may produce electrolyte imbalance
 Liver function test usually normal
 In case hepatic metastasis, alkaline phosphate may be elevated
 Lactate dehydrogenase levels are also increased in colon ca
• Jonsson PE, Bengtsson G, Carlsson G, Jonson G, Tryding N. Value of serum 5-nucleotidase, alkaline phosphatase and gammaglutamyl
transferase for prediction of liver metastases preoperatively in colorectal cancer. Acta Chir Scand 1984;150:419–23.
• Ioannou GN, Rockey DC, Bryson CL, Weiss NS. Iron deficiency and gastrointestinal malignancy: a population-based cohort study. Am J
Med 2002;113:276–80.

15. CARCINOEMBROYONIC ANTIGEN ( CEA) LEVELS
 Moderate sensitivity and poor specificity
 Very high levels in advanced disease
 Preoperative testing to be done to :
 Determine cancer prognosis
 To determine baseline levels for postop comparison
 Elevated pre-op levels – poor prognosis
 Failure to normalise after surgery – incomplete resection
 Sustained and progressive rise after post-op normalisations -
recurrence
• Fletcher RH. Carcinoembryonic antigen. Ann Intern Med 1986;104:66–73.
• Arnaud JP, Koehl C, Adloff M. Carcinoembryonic antigen (CEA) in diagnosis and prognosis of colorectal carcinoma. Dis Colon
Rectum 1980;23:141–4.
• Koch M, Washer G, Gaedke H, McPherson TA. Carcinoembryonic antigen: Usefullness as a postsurgical method in the detection
of recurrence in Dukes stages B2 and C colorectalcancers. J Natl Cancer Inst 1982;69:813–5.

16. FAECAL OCCULT BLOOD TESTING ( FOBT)
 Traditional mainstay of screening for colon cancer
 Based on increased microscopic rectal bleeding in patients with
colon cancer compared with patients without colonic bleed
 Tested by calorimetric assay of reaction on guaiac catalysed by
pseudoperoxidase in blood
 Sensitivity under ideal circumstances – 85%
• Church TR, Ederer F, Mandel JS. Fecal occult blood screening in the Minnesota Study: sensitivity of the screening test. J Natl
Cancer Inst 1997;89:1440–8.

17. Advantages :
 Low cost
 Test simplicity
 Noninvasiveness
 Safety
Disadvantages :
 Low specificity
 Moderate sensitivity ( 85%)

18.  Sensitivity improved by :
 Performing test on three different occasions
 Avoiding ascorbic acid for several days
 Performing test on fresh stool or by rehydrating the stool
 Specificity improved by :
 Avoiding ingestion of broccoli, cauliflower , red meat
 Avoiding therapy with aspirin for 3 days before test
 Withholding iron therapy for several days
 Despite of its flaws, FOBT is an important armamentarium of colon
cancer screening because of test safety and convenience

19. CONTRAST ENEMA
 Valuable adjunct to colonoscopy for near obstructing colonic
lesions
 Ideally , barium-air double contrast technique used after bowel
preparation
 In acute settings and where there is suspicion of perforation,
barium is contraindicated due to risk of peritonitis
 In these cases water soluble contrast ( gastrograffin) is used

20. FINDINGS
 Fixed filling defect with destruction of mucosal pattern in an
annular configuration ( apple core sign )

21. Advantages :
 Visualises the anatomic position of the lesion more accurately
 Better passage through even severe obstructed lesion
 Commonly reach upto caecum
 Superior in visualising diverticula or suspected fistula
Disadvantages :
 Inability to take biopsy
 Inability to detect small lesion
Air Contrast Barium enema image shows
pouches (called diverticula) in the wall of the
colon

22. FLEXIBLE SIGMOIDOSCOPY
 Flexible sigmoidoscopy every 3 to 5 years recommended in
conjunction with annual FOBT for screening of colon cancer in
average risk patients
 Role is becoming increasingly limited in screening of colon cancer
due to :
 Proximal half of colon not visualised and about 1/3 to ½ of lesions
are proximal to sigmoid colon
 Recent shift of colon cancers to right side of colon
 Most proximal lesions do not have synchronous distal lesions
 Finding cancer on sigmoidoscopy mandates full colonoscopy to
diagnose synchronous lesions

23. DIAGNOSTIC COLONOSCOPY
 Has evolved as method of choice for evaluation of large intestine
 Recommended for screening of patients > 50 years old at average
risk for colon cancer
 Highly sensitive in detecting large ( >1 cm ) polyps, with miss rate of
about 6%
 Moderately sensitive in detecting diminitive ( < 0.6 cm ) polyps, with a
miss rate of about 27%
 Colon cancers are rarely missed because of their large size as
compared to adenomas

24. Indications of colonoscopy :
Surveillance in persons with average and high risk for colon cancer
Faecal occult blood
Iron deficiency anaemia
Haematochezia
Malaena with nondiagnostic UGI endoscopy
After finding colonic polyps on sigmoidoscopy
Adenocarcinoma metastasis to liver with unknown primary
Follow up after colonoscopic removal of large sessile colonic polyp
Abnormal radiographic study ( contrast enema, virtual colonoscopy)
Colonic stricture
Intraoperative colonoscopy to localise lesion for surgical removal

25.  In colonoscopy, Polyps are characterised by :
 Size
 Color
 Number
 Segmental location
 Intramural location ( mucosal or submucosal)
 Presence or absence of stalk ( pedunculated or sessile )
 Superficial appearance

26.  Polyp characteristics at colonoscopy provides important clues
regarding polyp histology and malignant potential
 Hyperplastic polyps are small, pale, unilobular and located in
rectum

27.  Adenomas are larger, redder, multilobular and distributed
throughout colon
A typical tubular adenoma in the colon Picture of Familial Adenomatous Polyposis

28.  Villous adenomas are large, bulky, sessile, shaggy, soft, velvety,
and friable

29.  Advanced colon cancer typically appears either as :
 large, exophytic mass because of intraluminal growth
 a colonic stricture because of circumferential growth
 Malignant strictures are ulcerated, indurated, asymmetric and
friable and have irregular or overhanging margins
Exophitic colon cancer
A malignant stricture (adenocarcinoma) in
the transverse colon

30. Disadvantages of colonoscopy :
 Expensive
 Invasive
 Uncomfortable and requires sedation and analgesia
 Small, but significant, risk of serious complications
 Requires a team of technician, nurse and trained
colonoscopist
 Requires patient preparation for 24 hours before test

31. Complications :
Diagnostic colonoscopy-associated perforation.
 Complication rate is about 5 %
 Most common major complications are GI bleed and
perforation
 Most colonic perforations require surgery but conservative
management with parenteral fluids, antibiotics and surgical
backup occasionally suffices

32. COMPUTED TOMOGRAPHY
 Standard modality to image the abdomen in colorectal ca
 CT is highly sensitive (90%) and specific ( 95%) in detecting
liver metastasis > 1cm
 CT is only moderately accurate in detecting T staging ( 74%)
and N staging ( 50-70 %)

33. CT showing multiple liver metastasis( arrows) in a patient
of Colon cancer

34. MAGNETIC RESONANCE IMAGING
 Superior to CT in detecting liver metastasis
 More sensitive than CT, particularly in detecting small
metastasis
 Sensitivity is increased even more in contrast enhanced
MRI as the metastatic lesion is enhanced due to high
vascularity
 Usually reserved for characterizing ambiguous hepatic
lesions detected on abdominal USG or CT

35. MRI (T2 with fat suppression) demonstrating rounded
high-intensity metastatic lesions (arrows) throughout the
liver in a patient with known colon cancer

36. COLONIC ULTRASONOGRAPHY
 Endoscopic ultrasound is much more useful for T and N
staging of rectal cancer as compared to colon cancer
 Most patients with colon cancer without distant mets
undergo colonic resection irrespective of T or N stage
 Colonic endosonography is also technically more demanding
and time consuming

37. Endoscopic ultrasound showing tumour in sigmoid colon

38. NEW AND EVOLVING
INVESTIGATIONS

39. STOOL GENETIC MARKERS
 This technique has showed clinical promise in preliminary
clinical studies
 Based on detection of cancerous DNA in stool specimen
 DNA from colon cancer is shed in greater quantities in the
faecal stream than normal mucosa
 Minute quantities of DNA in stool can be amplified by PCR
technique

40.  The DNA can then be assayed for detection of mutations of
colon cancer ( like APC, p53, K-ras )
 Sensitivity in different studies ranges from 71-91 %
 It has the potential of non-invasiveness and user
friendliness
 Technique need refinement and testing in large clinical trials

41. VIRTUAL COLONOSCOPY
 Introduced by Vining in 1994
 CT images are obtained in prone and supine position during a
prolonged breath hold
 CT images are then reformatted into three dimensional
endoluminal images simulating the traditional colonoscopic view
 There is a wide discrepancy in sensitivity an specificity in different
studies
 Accuracy of virtual colonoscopy is a function of polyp size. More
accurate in detecting lesion >10mm than lesion < 5mm

42. Virtual colonoscopy image of the inside of a colon. The red
colored area indicates a polyp detected by computer-aided
detection (CAD)
Computerized Tomographic Colonography (CTC) images of a
colon (left, with the patient scanned supine; right, with the patient
scanned prone). The red colored area indicates a polyp detected
by computer-aided detection (CAD).

43. Advantages :
 Noninvasive
 Sedation and analgesia not required
 Safe with hardly any reported complication
 Can visualise extracolonic, intraabdominal organs and thus can
provide simultaneous cancer staging
Disadvantages :
 Inability to take biopsy
 Inability to remove polyps for HPE and definitive therapy