Although the prevalence of some cancers has declined, that of colon cancer has increased, and the rise is thought to reflect socioeconomic affluence. Inheritance contributes a little (about 5-10%) to the causation of this disease, whereas dietary and environmental factors have a large influence. Knowledge that low-fibre, high-calorie diets contribute to the development of colorectal cancer has led to the use of systematic dietary interventions for reducing the incidence of this cancer. Molecular understanding of carcinogenesis has led to the identification of new targets such COX-2. These in turn has led to the prophylactic use, with some success, of drugs such as COX-2 inhibitors, non-steroidal anti-inflammatory agents(NSAID’s) folate, cholestyramine and calcium (latter two for their bile-salt-binding action).

The stepwise nature of tumorigenesis was first observed and has been best worked out in colon cancer. It is well understood that certain polyps are precursors to most colon cancers. This point is the basis for strategies for the early detection and screening of colon cancers, with flexible sigmoidoscopy, colonoscopy, and barium enemas being used to detect polyps. Also, since bleeding from early mucosal carcinoma may be the first sign of the cancer, screening for occult blood in the faeces is well entrenched as an important yet simple test in normal-risk health screening for people aged above 50. With more advanced disease symptoms of obstruction of the lower gastrointestinal tract may appear.

A vast number of medical professionals are involved in the management of colorectal cancer, not only because of its high prevalence but also because its screening, diagnosis, definitive treatment, and palliative treatment involve a wide range of generalists and specialists. In this issue of Cancer Update many such specialists at NCC present an all-round view of colorectal cancer and specific aspects of management of this cancer. Happy reading!

Dr Sandeep Rajan, Editor