Utilization of neoadjuvant therapy for localized gastric gastrointestinal stromal tumors and the association with survival

Background: For gastric gastrointestinal stromal tumors (GISTs), neoadjuvant imatinib is most often reserved for tumors near the gastroesophageal junction, multivisceral involvement, or limited metastatic disease. Whether localized gastric GISTs benefit from neoadjuvant therapy (NAT) remains unknown. We sought to examine factors associated with NAT utilization for localized gastric GISTs and evaluate implications on survival. Methods: The National Cancer Database identified patients with localized gastric GISTs treated with NAT (2010–2020), excluding tumors extending beyond the gastric wall, located in the cardia, or with metastatic disease. Multivariable logistic regression assessed characteristics of NAT use. After 1:1 propensity score matching, Kaplan-Meier methods and multivariable Cox regression assessed overall survival (OS). Results: Of 7203 patients, 762 (10.6%) received NAT followed by resection. On multivariable analysis, increasing tumor size was associated with NAT use (<2.0 cm vs 2.0–5.0 cm [odds ratio {OR}, 2.03; 95% CI, 1.19–3.47; P = .010] vs >5 cm [OR, 16.87; 95% CI, 10.02–28.40; P < .001]). After propensity score matching, 1506 patients remained. Median OS for NAT was 46.0 months vs 43.0 months for resection (P = .059), which was independently predictive of improved survival on multivariable analysis (hazard ratio [HR], 0.89; 95% CI, 0.80–0.99; P = .041). Subgroup analysis by tumor size showed no survival differences for tumors <2.0 cm or from 2.0 to 5.0 cm. Median OS was higher for tumors > 5.0 cm treated with NAT (NAT, 45.4 months [IQR, 29.5–65.9] vs upfront resection, 42.3 months [IQR 26.9–62.8]) and associated with improved survival on multivariable analysis (HR, 0.88; 95% CI, 0.78–0.99; P = .040). Conclusion: Although patients who received NAT had improved survival, this was primarily due to tumors >5.0 cm. Expanding NAT selection criteria to include localized gastric GISTs >5.0 cm may improve outcomes and warrants investigation through clinical trials.