Proposed staging system for colon carcinoid tumors based on an analysis of 2,459 patients

Colon carcinoid remains an uncommon finding during screening endoscopy or operation, with little known about the longterm prognosis. The reason for this uncertainty is that no staging system exists to appropriately risk stratify or follow these patients for overall survival. We sought to investigate prognostic factors associated with colon carcinoid tumors and create a predictive staging system to accurately estimate prognosis.

A search of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database identified 15,983 patients with carcinoid tumors, with 2,459 from the colon, from 1973 to 2004. Patients were analyzed to various clinicopathologic factors and a tumor (T1, T2, T3), lymph node (N0, N1), and metastasis (M0, M1) staging system was created according to these parameters.

Of the 2,459 patients, 1,287 (52%) women and 1,172 (48%) men were identified, with a median age of 63 years (range, 12 to 96 years). Lymph node metastasis was found in 820 (48%), and distant metastatic disease was present in 522 (24%) patients. On multivariate analysis, age, size, depth of invasion, lymph node involvement, distant metastasis, and location were significant. Four stages were created to statistically significant prognostic factors: 13% into stage I, 32% into stage II, 12% into stage III, and 43% into stage IV. Five-year survival rates were 97%, 69%, 21%, and 17% for stages I through IV (p = 0.001).

The newly developed TNM staging system accurately discriminates prognosis for carcinoid tumors of the colon. Incorporation of this staging system into clinical practice will allow better study of outcomes and development of stage-specific treatment recommendations.