Colorectal cancer. Some aspects of epidemiology, risk factors, treatment, screening and survival.
In developed populations colorectal cancer, which after lung cancer is the commonest of cancers, accounts for up to 6% of all deaths. It occurs most frequently in populations in prosperous industrialised countries, save Japan, and is rare in Third-World populations pursuing a traditional lifestyle. Peak occurrence is in the 7th decade. Colon cancer affects the sexes equally, but males are much more prone to rectal cancer. The precise causation is uncertain. Risk factors include genetic or familial predisposition, inflammatory bowel disease, diet (especially high fat and low dietary fibre intakes), and possibly alcohol intake. Surgery remains the treatment of choice. Stage is by far the most important factor influencing prognosis. Major refinements in both surgical and therapeutic measures have had disappointingly little effect on survival time. Overall median mortality occurs in 1-1 1/2 years; only one-third to one-half of patients survive for 5 years. While effective screening for very early detection could increase survival time, this will result only from further education. Since little avoiding action is practicable, the outlook for patients will remain daunting until help is sought far earlier.
Walker
A R
AR
Department of Tropical Pathology, School of Pathology, University of the Witwatersrand, Johannesburg.
Segal
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D000328:Adult; D000368:Aged; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology; D012307:Risk Factors