A proposed staging system for gastric carcinoid tumors based on an analysis of 1,543 patients.

The lack of a clinically relevant staging system for gastric carcinoid tumors creates a persistent challenge for clinicians trying to provide patients with meaningful prognostic information. The purpose of this study was to identify the clinicopathologic factors that affect survival for patients diagnosed with gastric carcinoid, and use this information to create a staging system. A search of 15,983 patients with carcinoid tumors from the Surveillance Epidemiology and End Results (SEER) database identified 1,543 patients with gastric carcinoid tumors from 1973 to 2004. Patients were analyzed according 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. Gastric carcinoid was the only primary malignancy in 74% of patients; 24% presented with one additional primary malignancy, and 2.7% had two or more additional malignancies. On multivariate analysis, age and depth of invasion were significant for patients with one tumor. Four stages were created according to statistically significant prognostic factors: 60% of patients were classified into stage I, 7.6% into stage II, 6.5% into stage III, and 26% into stage IV. Five-year survival rates were 82, 63, 21, and 5.5% for stages I-IV, respectively. We conclude that this tumor-node-metastasis (TNM) staging system accurately discriminates prognosis for all types of gastric carcinoid tumors, with size, depth of invasion, lymph node involvement, and distant metastasis having the greatest impact on survival. Incorporation of this staging system into clinical practice will allow better study of outcomes and development of stage-specific treatment recommendations.