Multiple colorectal tumors. An appraisal of natural history and therapeutic options.

The clinical course of 101 patients with multiple colorectal carcinomas treated during a 15 year period is documented; 2.8 percent of all patients with colorectal cancer had metachronous tumors and 1.7 percent had synchronous lesions. The median interval between metachronous tumors was 9 years. The symptom duration was shorter before discovery of the second metachronous tumors, yet the second tumors were more malignant than the primary ones. Patients with synchronous tumors were older than those with single colon cancers or initial metachronous lesions. Synchronous tumors were more apt to occur on the right side of the colon than single tumors. Adenomatous polyps were present in the resected specimens 37 to 63 percent of the time. The overall uncorrected 5 year survival rate was only 21 percent. Among 20 patients having subtotal colectomy, the operative mortality was 10 percent. Eleven of 18 survivors of subtotal colectomy were free of disease 2 to 13 years later (average 5.5).