Cancer Of Colon And Rectum

Overview

Colorectal cancer is one of the most common type of gastrointestinal cancer. It usually begins as small, benign clumps of cells called polyps that form on the internal lining of the colon. Over time some of these polyps can transform into malignant tumour. The disease men and women equally. Colorectal cancer seems to occur less frequently in the developing world than in industrialised countries.

Signs and Symptoms

Change in bowel habit:common symptom of left sided tumour, Rectal bleed, Iron deficiency anemia:common symptoms of proximal lesion, Mass, Persistent abdominal discomfort, Feeling of ‘bowel not empty' after defecation, Weight loss, Loss of appetite, Fatigue and weakness

Common Causes

Arises from adenomatous polyps after a sequence of genetic mutations influenced by environmental factors, Mutation of APC gene: found in both carcinoma and adenomas, Mutation of K-ras gene: larger lesion and poorer prognosis, Mutation of p53 gene: found in carcinomas

Risk Factors

History of polyps or colorectal cancer, Chronic inflammatory disease: Crohn's disease and ulcerative colitis, Inherited syndromes: Familial adenomatous polyposis(FAP) and Hereditary nonpolyposis colorectal cancer(HNPCC), Family history of colon cancer, Low fibre and high fatty diet, Sedentary life, Smoking, Alcohol intake

Investigation Techniques

Flexible sigmoidoscopy, Colonoscopy, Tissue biopsy, Double -contrast barium enema, Spiral CT of the chest and abdomen (also used for staging), Chest X-ray and liver ultrasound for staging (alternative to CT), CT virtual colonoscopy, Serum CEA level for bio-marker

Treatment and Prevention

Early stage: Colonoscopic removal of polyp, endoscopic mucosal resection Advanced stage: right hemicolectomy, extended right hemicolectomy, left hemicolectomy, lymph node resection Emergency: Hartmann's procedure, resection and anastomosis Chemotherapy Radiotherapy Palliative care Lifestyle management: high fibre diet, reduction in alcohol intake, cessation of smoking, exercise