[Familial colon cancer].

5 families with autosomal dominant inherited colonic cancer were analyzed with reference to the characteristics of familial colonic cancer: 45% out of 54 family members had colorectal carcinomas, with a mean of 4.5 affected members per family. The mean age on diagnosis of colonic cancer was 43.9 years. 50% of the colorectal carcinomas were located in the right colon; 11 out of 14 carcinomas were Dukes C, with a predominance of poorly differentiated adenocarcinomas and mucin-producing cancers. 22% had synchronous cancers and 13% developed metachronous cancers. Cancer at another location was found in 8.7% of cases. Prospective screening of relatives (siblings, children) revealed a colonic neoplasm in 3 out of 6 asymptomatic subjects. The typical characteristics of familial colonic cancers were demonstrable in our patients. The elucidation of an exact family history in all patients with colorectal carcinoma and a strategy of meticulous surveillance are absolutely necessary for the diagnosis and management of this inherited trait.