Carcinoid tumors of the rectum: Effect of size, histopathology, and surgical treatment on metastasis free survival

BACKGROUND. The purpose of this study was to determine the clinical course, effects of specific tumor histopathologic characteristics, and extent of surgical treatment on the metastatic rate in patients with rectal carcinoids. METHODS. Medical records of 44 patients who presented with rectal carcinoids were retrospectively reviewed. Primary tumors were classified by size (< 1 cm, 1-2 cm, and >2 cm), and tumor histopathologic features (atypical or typical). Extensive surgery was defined as abdominoperineal or low anterior resection of the rectum or laparotomy with intent of curative resection. RESULTS. Median follow-up for patients who presented without metastasis was 84 months. Thirteen of the 44 patients (30%) presented with metastatic disease. The 5-year metastasis free survival rates for those patients presenting without metastatic disease were 100% for patients with tumors < 1 cm (n = 16), 73% for those with tumors 1-2 cm (n = 8), and 25% for those with tumors > 2 cm (n = 4) (P = 0.04 comparing <1 cm with 1-2 cm and P = 0.05 comparing 1-2 cm with >2 cm); tumor size data were not available for 3 patients. The 5-year metastasis free survival rate for patients presenting without metastatic disease with typical histology (n = 20), regardless of size, was 100%, compared with 50% for patients with tumors with atypical histology (n = 11) (P = 0.001). Nine patients underwent extensive surgery for rectal carcinoid tumors but no survival benefit was demonstrated. CONCLUSIONS. Atypical histopathologic features and a tumor size > 1 cm are associated with aggressive behavior of rectal carcinoid tumors. Extensive surgery offers no survival advantage over local excision for patients with rectal carcinoid tumors.