Treatment of gastric neuroendocrine tumors - The necessity of a type-adapted treatment

Background: Gastric neuroendocrine (or gastric carcinoid) tumors have recently been classified into 3 types that differ in biological behavior and prognosis. Although the necessity of type-adapted treatment is widely accepted, it seems inconsistently used in daily practice. Hypothesis: Diagnostic differentiation into various biological types is necessary for an adequate treatment of gastric neuroendocrine tumors. Design: Retrospective study. Setting: University hospital department of surgery. Patients: Twenty-seven patients with a histologically verified gastric neuroendocrine tumor. Main Outcome Measures: A univariate analysis of survival rates with respect to tumor type, tumor biological parameters, and treatment performed was accomplished by applying the Kaplan-Meier estimation method. The log-rank test was used to evaluate the level of significance. Results: The 16 type 1 (59%) and 11 type 3 (41%) gastric neuroendocrine tumors differ in tumor size, histopathologic characteristics, and biological behavior. Nine (56%) of 16 type 1 gastric neuroendocrine tumors were treated by local excision, 8 of these (89%) had persistent atrophic gastropathy during the follow-up period. Five-year cumulative survival of patients with type 1 gastric neuroendocrine tumor was 100% without any progression into malignant phenotype. In contrast, 4 (44%) of 9 locally advanced type 3 gastric neuroendocrine tumors were treated radically by extended resection with a 5-year cumulative survival of 75%. Conclusions: Differentiation into 3 biologically distinct tumor types for gastric neuroendocrine tumors is important with respect to therapeutic strategy and prognostic consideration. Correct diagnosis is attainable by using endoscopy, histopathologic characteristics, and laboratory chemical analysis and should precede any treatment. Extended radical surgery of high-risk type 3 tumors is indicated when definitive healing is achievable, whereas type 1 tumors are best treated by endoscopic removal and long-term follow-up.