Carcinoid Tumors of the Rectum A Multi-institutional International Collaboration

Objective: This study aims to describe recent experience with rectal carcinoids in European and North American centers. Background: While considered indolent, the propensity of carcinoids to metastasize can be significant. Methods: 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). Results: 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%. Conclusion: 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.