Adjuvant systemic therapy for small bowel gastrointestinal stromal tumor (GIST): Is there a survival benefit after R0 resection?

Abstract

Background: The utility of adjuvant systemic therapy in small bowel gastrointestinal stromal tumor remains unclear.

Methods: We queried the National Cancer Data Base for individuals having enterectomy to negative margins for small bowel gastrointestinal stromal tumor between 2010 and 2015. Subjects were categorized by tumor size (2.1-5 cm, 5.1-10 cm, >10 cm) and histologic grade (≤5 mitoses/50 high-power field and >5 mitoses/50 high-power field). Cox proportional hazard analysis was performed to evaluate the association between adjuvant therapy and overall survival.

Results: One thousand five hundred fifty-nine patients met the inclusion criteria. On univariate comparison to resection alone, adjuvant therapy was associated with improved overall survival for individuals with high-grade tumors of intermediate and large size (85% vs 48%, P = .010; 75% vs 47%, P = .003) but not for those with high-grade tumors of small size or low-grade tumors of any size. On multivariable analysis adjusted for age, comorbid disease state, and tumor size, adjuvant therapy was independently associated with reduced risk of mortality for high-grade (hazard ratio 0.37, 95% confidence interval: 0.21-0.64) but not low-grade tumors.

Conclusion: Adjuvant therapy after R0 resection for small bowel gastrointestinal stromal tumor should be administered after careful consideration of the size and grade of a patient's tumor.