SHER-I-KASHMIR INSTITUTE OF MEDICAL

SCIENCES

CLINICAL FEATURES AND INVESTIGATIONS

IN

CARCINOMA COLON

PREPARED BY

DR IFRAH AHMAD QAZI

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

CLINICAL FEATURES

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

Less common symptoms

Nausea and vomiting

Malaise

Anorexia

Abdominal distention

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

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

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

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

DIAGNOSIS

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

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

SCREENING

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.

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.

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.

Advantages :

Low cost

Test simplicity

Noninvasiveness

Safety

Disadvantages :

Low specificity

Moderate sensitivity ( 85%)

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

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

FINDINGS

Fixed filling defect with destruction of mucosal pattern in an

annular configuration ( apple core sign )

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

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

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

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

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

Polyp characteristics at colonoscopy provides important clues

regarding polyp histology and malignant potential

Hyperplastic polyps are small, pale, unilobular and located in

rectum

Adenomas are larger, redder, multilobular and distributed

throughout colon

A typical tubular adenoma in the colon Picture of Familial Adenomatous Polyposis

Villous adenomas are large, bulky, sessile, shaggy, soft, velvety,

and friable

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 cancerA malignant stricture (adenocarcinoma) in

the transverse colon

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

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

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 %)

CT showing multiple liver metastasis( arrows) in a patient

of Colon cancer

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

MRI (T2 with fat suppression) demonstrating rounded

high-intensity metastatic lesions (arrows) throughout the

liver in a patient with known colon cancer

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

Endoscopic ultrasound showing tumour in sigmoid colon

NEW AND EVOLVING

INVESTIGATIONS

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

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

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

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).

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