Rectal carcinoid tumors--treatment and prognosis.

Because of their location, rectal carcinoid tumors present a special therapeutic challenge for the surgeon. Only about 15% of these tumors manifest metastases and the others can be cured by complete local excision; hence performing a low anterior resection or an abdominoperineal resection for all patients would result in excessive rates of morbidity and death. Present-day treatment programs call for radical cancer resections only for lesions 2 cm in diameter or larger and local resection for all others. However, in a review of 595 patients, including 29 from the University of Chicago Hospitals, it was determined that this practice results in undertreatment of 24% (19/78) of all rectal carcinoid tumors that were associated with metastases, for 5% of all lesions smaller than 2 cm also had metastases. Invasion of the muscularis propria, we found, was an excellent additional prognostic sign for tumor progression. If the criteria for radical cancer resection included both size (all tumors 2 cm or larger and invasion of the muscularis propria in all smaller lesions, only 6% (5/78) of all aggressive tumors would have been missed and only 1.2% of all individuals with rectal carcinoid tumors would have received too limited an operation. It is hoped that the use of these new criteria will improve present-day survival statistics for patients with rectal carcinoid tumors.