Clinical significance of surgical intervention for imatinib-resistant gastrointestinal stromal tumors in the era of multiple tyrosine kinase inhibitors

Imatinib is the standard treatment for unresectable and metastatic GIST. In the late stages, patients undergoing imatinib show drug resistance. Surgical intervention has been occasionally performed for resistant lesions. However, the clinical significance of such intervention remains unclear. Between 2006 and 2015, 37 patients were diagnosed with imatinib-resistant GISTs. We performed surgical intervention only for localized resistant lesions. We retrospectively investigated the background characteristics, data on surgical intervention and subsequent treatment, progression-free survival (PFS), and overall survival (OS). Eighteen patients diagnosed with localized resistance received surgical intervention (S-group) and 19 patients diagnosed with generalized resistance were received other TKIs (M-group). In S-group, no serious complications occurred, and all patients restarted imatinib after resection. The median PFS was 14.5 months. Five patients underwent surgical intervention multiple times followed by the continuation of imatinib, and the median duration of imatinib continuation was 22.2 months. Second-line TKIs were administered to 93% of the patients and the dose-intensity and outcome were similar in both groups. The median OS was 47.2 months after surgery. Surgical intervention could be performed safely and therefore could be followed by the continuation of TKI therapy. Surgical intervention based on the appropriate criteria of resistance might thus be useful for imatinib-resistant GISTs.