[Proximal and distal cancers of the colon: 2 epidemiologically different cancers].

During a seven year period ending in 1984, the Calvados Registry of Digestive Tract Tumors (France) recorded 1446 cases of colorectal cancer. The sex-ratio, age, and histologic type were studied with respect to location. From cecum to rectum, the sex-ratio varied from 1 to 1.9. Average age at diagnosis varied between 67.5 and 72.6 years for women but was invariable for males. The proportion of mucinous carcinoma varied between 13 p. 100 in the cecum and 5 p. 100 in the sigmoid and rectum. The study of incidence with respect to age and location showed that there were less elderly women with left colonic and rectal carcinoma. Epidemiologically, there seems to be two different types of colonic carcinoma: proximal and distal colonic carcinoma (including the rectum), the separation being determined by the splenic flexure.