Appendiceal Carcinoid Tumors: Is There a Survival Advantage to Colectomy over Appendectomy?

BACKGROUND: Guidelines recommend colectomy for appendiceal carcinoid tumors larger than 2 cm, but physicians debate whether colectomy would be beneficial in treating smaller tumors. We sought to determine when colectomy confers a survival advantage over appendectomy.
METHODS: Appendiceal carcinoid patients in the US Surveillance, Epidemiology, and End Results (SEER) database (1988-2011) were stratified by age group, gender, TNM stage, tumor grade, and race. Kaplan-Meier and logistic regression analyses relating grade, stage, and receipt of colectomy to overall and cancer-specific survival were performed.
RESULTS: Of 817 patients who underwent surgical extirpation of an appendiceal carcinoid, 338 (41%) had appendectomy alone and 479 (59%) had additional colectomy. Surprisingly, patients who underwent colectomy had worse cancer-specific survival (HR 1.98, 95% CI 1.32-2.98, p = 0.001) than those who underwent appendectomy, and colectomy did not confer a survival advantage over appendectomy in any subset analysis including low-grade or high-grade tumors, smaller or larger than 2 cm, or node-positive, non-metastatic tumors. Even when accounting for stage and grade, colectomy was not associated with significantly better survival rates. Furthermore, as colectomy frequency has increased over the last decade, the 5-year survival rate has trended down. The main predictors of cancer-specific mortality in carcinoid patients were high-grade (grades 3-4) and high-stage (node positive or metastatic) tumors.
CONCLUSIONS: Survival in patients with carcinoid tumor of the appendix is primarily determined by tumor grade and stage. Our study found no survival advantage to colectomy over appendectomy in a large cohort of patients with the disease. Further investigation is necessary prior to recommending change of practice for patients with appendiceal carcinoid tumors.