Prognostic Factors of Patients with Gastric Gastrointestinal Stromal Tumor after Curative Resection: A Retrospective Analysis of 406 Consecutive Cases in a Multicenter Study.

Background/purpose: Gastric gastrointestinal stromal tumors (GISTs) have a highly variable clinical course, and recurrent disease sometimes develops despite curative surgery. This study was undertaken to investigate the surgical role in treating gastric GISTs and evaluate the clinicopathological features of a large series of patients who underwent curative resection for gastric GISTs to clarify which features were independent prognostic factors.

Methods: The clinicopathological data of 406 patients with gastric GISTs who underwent curative resection at 4 university hospitals in Daegu, South Korea, from March 1998 to March 2012 were reviewed. All cases were confirmed as gastric GISTs by immunohistochemical staining, in which CD117 or CD34 was positive. Clinical follow-up was performed periodically, and disease-free survival rates were retrospectively investigated using the medical records.

Results: The mean follow-up period was 42.9 months (range: 2-166). There were 11 recurrent patients (2.7%). Due to the small number of recurrences, age, sex and location were controlled using propensity score matching before performing any statistical analysis. Tumor size, mitotic count, NIH classification, and cellularity were judged to be independent prognostic factors for recurrence by univariate analysis. In a multivariate analysis, tumor size and mitotic count were significantly and independently related to recurrence, and tumor size was determined to be the most important prognostic factor for recurrence after curative resection (hazard ratio: 1.204; p < 0.01).

Conclusions: The results of this multicenter study demonstrate that disease-free survival rates are good. Tumor size was disclosed as the most important factor for recurrence in gastric GIST patients who underwent radical resection.