[Clinical and pathological studies of multiple primary carcinoma of the colon and rectum]

During a 5-year period from 1976-1981, we clinicopathologically studied 21 patients with 45 lesions of multiple primary colorectal carcinomas and compared our findings with those made in 288 single carcinomas of the large intestine. The frequency of multiple primary colorectal carcinoma was 6.8%. The pathological findings suggested an interrelationship between colorectal adenoma and carcinoma. Patients with multiple carcinomas of the large bowel had coexisting adenomas more than patients with single carcinoma. We suggest that it is necessary to do a thorough preoperative examination of cancer of the large intestine to detect double cancers or other adenomatous polypoid lesions with synchronous association.