Colorectal carcinoma: why is there a lower incidence in Nigerians when compared to Caucasians?

Carcinoma of the colon and rectum is the 2nd commonest cancer in the United States; the leading cancer being lung cancer. It has been estimated that 130,200 new cases of colorectal cancer will be diagnosed annually while 56,300 sufferers will die from the disease (Murphy et al., 2000). In developing countries especially West Africa, the rate has not yet reached such magnitude. This suggests that there may be factors either anthropomorphic or environmental which may be responsible for this. The paper acknowledges the reduced incidence of colorectal cancer in native West Africans living in Africa and endeavours to highlight the various factors that produce this observation in medical literature. A diligent search through available literature on the aetiology, epidemiology and comparative anthropology of colorectal cancer was done. Internet search using PubMed, British Library Online and Google Scholar was also utilized. The rarity of adenomatous polyposis syndromes in the native West African contributes to the reduced incidence of colorectal cancer. Cancer prevention and cancer-protective factors are deemed to lie in the starchy, high-fiber, spicy, peppery foodstuff low in animal protein which many West African nations consume.