clinical features and investigations in carcinoma colon
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
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
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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
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
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
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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
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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
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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 %)
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
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