Carcinoid tumors of the rectum: a multi-institutional international collaboration

This study aims to describe recent experience with rectal carcinoids in European and North American centers. While considered indolent, the propensity of carcinoids to metastasize can be significant. Rectal carcinoid patients were identified from prospective databases maintained at 9 institutions between 1999 and 2008. Demographic, clinical, and histologic data were collated. Median follow-up was 5 years (range, 0.5-10 years). Two hundred two patients were identified. The median age was 55 years (range, 31-81 years). The majority of tumors were an incidental finding (n = 115, 56.9%). The median tumor size was 10 mm (range, 2-120 mm). Overall, 93 (49%) tumors were limited to the mucosa or submucosa, 45 (24%) involved the muscularis propria, 29 (15%) extended into the perirectal fat, and 6 (3%) reached the visceral peritoneum. The primary treatment modalities were endoscopic resection (n = 86, 43%) and surgical extirpation (n = 102, 50%). Forty-one patients (40%) underwent a high anterior resection, whereas 45 (44%) underwent anterior resection with total mesorectal excision. Seven patients (7%) underwent Hartman's procedure, 7 (7%) underwent abdomino-perineal resection, and 6 (6%) had transanal endoscopic microsurgery, whereas 4 (4%) patients underwent a transanal excision. Multiple variable logistic regression analysis demonstrated that tumor size greater than 10 mm and lymphovascular invasion were predictors of nodal involvement (P = 0.006 and < 0.001, respectively), whereas the presence of lymph node metastases and lymphovascular invasion was associated with subsequent development of distant metastases (P = 0.033 and 0.022, respectively). The presence of nodal metastases has a profound effect upon survival, with a 5-year survival rate of 70%, and 10-year survival of 60% for node positive tumors. Patients with distant metastases have a 4-year survival of 38%. Tumor size greater than 10 mm and lymphovascular invasion are significantly associated with the presence of nodal disease, rendering mesorectal excision advisable. Transanal excision is adequate for smaller tumors.