[Successive cancers of the colon and rectum]

The incidence of successive cancers of the colon and rectum varies from 1.4% to 5.1%. Among 350 malignant colorectal tumours operated in our unit, there were 7 cases of successive cancers (2%). The mean interval between the discovery of the first and second cancer was 4.9 years with a range of 1 to 10 years, 3 cases before 2 years and 4 cases after 5 years. The diagnosis of the second cancer was made by coloscopy in 4 cases and was revealed by rectal bleeding in 4. CAE level was unchanged in all 7 patients and was not contributive to diagnosis. At diagnosis of the first cancer there were 5 intraparietal tumours including 2 with lymph node dissemination. At diagnosis of the second cancer, there were 5 cases of intraparietal tumours with 1 lymph node extension. An association with benign polyps was observed in 2 of the 7 cases at the first diagnosis and in 4 of the 7 at the second. Prophylaxy requires complete work-up with total coloscopy at the diagnosis of the first cancer. Segmentary colectomy is sufficient in patients over 65, but we prefer total colectomy in patients under 65.