Large-bowel malignancy. Epidemiology and gut motility studies in South Asia.

Two hundred thirty-two cases of colorectal malignancy were studied between January 1975 and March 1981. The material was analyzed with respect to various epidemiologic features such as age, sex, residence, religion, socioeconomic status, diet, bowel habits, site of bowel involved, acute obstructive symptoms, and histopathology. The disease afflicted predominantly old people but at an age earlier than is reported in most western studies. Rectal cancer was more common in males, while colonic cancer involved the two sexes equally. Acute large-bowel obstruction was found in 19.4 per cent of patients. The rectum was the most common site (41.8 per cent). Of all the colonic malignancies, 63.4 per cent were in the right colon. Simultaneously, normal gut transit studies using radiopaque markers were conducted in 30 healthy volunteers. The colonic transit rate was 3.09 cm/hour. The markers had a faster gut transit but, interestingly, exhibited pronounced stasis in the right colon, which correlates well with the significantly higher incidence of right-sided malignancy.