About Colorectal Cancer
Cancers of the large bowel and rectum are referred to collectively as colorectal cancer. These cancers are common in developed countries, but occur much less frequently in the developing world. In 2008, 1.2 million new cases of colorectal cancer were diagnosed worldwide and there were over 60,000 deaths related to this disease.1
Most cases of colorectal cancer (approximately 70%) are non-hereditary and preventable.2
About 20% of cases have a hereditary or familial component.2 Besides family history, other risk factors for colorectal cancer include older age, inflammatory bowel disease, diets high in fat and/or red meat, and a sedentary lifestyle.3
Approximately 80% of colorectal cancers originate from mushroom-shaped growths in the gut called polyps.4Although most polyps are benign, others can become cancerous and spread beyond the gut wall. Screening helps to identify polyps and localized tumors and prevent the development of advanced disease.
Benign Colon Polyp
More than 95% of colorectal cancers arise from the glandular epithelium that lines the gut, and are called adenocarcinomas. Other types of tumors that start in the colon and rectum, for example carcinoid tumors and gastrointestinal stromal tumors (GISTs), occur infrequently by comparison.
The symptoms of colorectal cancer can be non-specific and may not be evident during early stages of the disease. They include bleeding, changes in appetite and bowel habits, abdominal pain, weight loss and weakness. Colorectal cancer is typically diagnosed on the basis of colonoscopy and biopsy.
1. Ferlay J, Shin HR, Bray F, et al. GLOBOCAN 2008, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 10 [Internet]. Lyon,
France: International Agency for Research on Cancer; 2010. Available from: http://globocan.iarc.fr
2. Benson AB 3rd. Epidemiology, disease progression, and economic burden of colorectal cancer. J Manag Care Pharm 2007;13(6 Suppl C):S5-18
3. Fearon ER, Bommer GT. Molecular Biology of Colorectal Cancer, In: DeVita VT, Lawrence TS, Rosenberg SA (Eds) Cancer: principles and
practice of oncology, 8th edition
4. Cunningham D, Atkin W, Lenz HJ, et al. Colorectal cancer. Lancet 2010;375:1030-47