[Multiple cancers of the colon and rectum. Incidence and results of surgical treatment].

Out of 1,528 patients operated upon for cancer of the colon or rectum between 1964 and 1984, synchronous carcinomas were observed in 63 patients, metachronous carcinomas in 36 patients and both synchronous and metachronous carcinomas, in 3 patients. Synchronous carcinomas were double in 59 patients and triple in 4 patients. In 80 p. 100 of the cases, the lesions were confined to the same surgical segment or to an adjacent segment. Rectal locations were less frequent (18 p. 100). Preoperative diagnosis was made in only 40 p. 100 of cases. Ninety-three p. 100 had resection, 81 p. 100 with a curative intent. Associated benign polyps were found on the resected specimen in 58 p. 100 of the cases. The resectability rate (93 p. 100) and 5-year survival rate (55 p. 100 of all operated patients and 67 p. 100 of those who underwent curative resection) were similar to those observed in our personal series of single carcinomas of the colon. A second cancer of the colon or rectum occurred in 36 patients. The time interval between the first and second carcinomas ranged from 1 to 24 years and the mean interval time was 6.3 years. Three of the 36 patients developed a third metachronous lesion. The distribution of the sites of successive carcinomas was similar to that of synchronous carcinomas; the second carcinoma was located in the rectum in 8 p. 100 of cases. Diagnosis of the second carcinoma was made through routine periodic colonoscopy in one third of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)