Cancer-directed surgery for metastatic gastric GISTs is associated with improved survival: an observational study


Year:

Session type:

Theme:

Apostolos Gaitanidis1,Michail Alevizakos2,Michail Pitiakoudis1
1Democritus University of Thrace Medical School,2University of Pittsburgh Medical Center

Abstract

Background

Most patients with metastatic gastrointestinal stromal tumors (GISTs) receive treatment with imatinib, but the clinical benefits of both cancer-directed surgery and resection of metastatic sites are not known. The purpose of this study is to identify whether patients with GISTs and distant metastases at diagnosis benefit from surgical resection.

Method

Patients with GISTs and distant metastases at diagnosis were identified using the Surveillance Epidemiology and End Results (SEER) database. Both disease-specific survival (DSS) and overall survival (OS) were used as outcomes. Survival analysis was performed using the log-rank test and Cox proportional hazards model.

Results

Overall, 1 136 patients were identified with a diagnosis between 2004 and 2013. Both cancer-directed surgery (DSS: p<0.001; OS: p<0.001) and resection of distant sites (DSS: p=0.002; OS: p<0.001) were significantly associated with improved survival on univariate, but not multivariate analysis for the entire cohort. However, a sub-analysis of gastric tumors showed that cancer-directed surgery was the most significant independent predictor of both improved DSS (median survival: not reached vs. 39 months; HR=3.95; 95% CI: 1.77-8.78; p=0.001) and OS (median survival: 92 months vs. 30 months; HR=3.07; 95% CI: 1.56-6.02; p=0.001) on multivariate analysis. Sub-analysis for either small intestinal or colorectal/anal tumors did not identify cancer-directed surgery as an independent predictor of either improved DSS or OS.

Conclusion

Surgery for gastric GISTs with distant metastatic disease at the time of diagnosis is independently associated with improved survival. Surgery may not be beneficial for patients with small intestinal and colorectal GISTs and distant metastatic disease.