Microwave ablation with continued EGFR tyrosine kinase inhibitor therapy prolongs disease control in non‐small‐cell lung cancers with acquired resistance to EGFR tyrosine kinase inhibitors

Background Although patients with EGFR ‐mutant non‐small‐cell lung cancer (NSCLC) benefit from treatment with EGFR‐tyrosine kinase inhibitors (TKIs), outcomes are limited by the eventual development of acquired resistance. We conducted a retrospective study to evaluate the efficacy and feasibility of EGFR‐TKI therapy beyond focal progression, associated with microwave ablation. Methods Patients with metastatic EGFR ‐mutant NSCLC treated with EGFR‐TKIs at our institutions from May 2012 to December 2017 were identified. Patients with single lesion progression, treated with MWA, and continually administered EGFR‐TKI therapy until further progression, were included in the study. Initial response to target therapy, median progression‐free survival (PFS1), and first progression site were recorded. The median time to progression after local therapy (PFS2) was also assessed. Overall survival was calculated from the initiation of EGFR‐TKIs to the date of final follow‐up or death. Results Fifteen out of 205 patients (10%) satisfied the inclusion criteria. Local therapy was well tolerated, and complete ablation was performed in 11 (73.3%) patients. The median PFS1 was 9.5 months (range 6–41), and the median PFS2 was 8 months (range 3–24). The corresponding 6 and 12 month PFS rates were 73.3% and 26.7%, respectively. Median overall survival was 23 months (range 15–64). Conclusion The longer disease control observed in our patients suggests that continuation of EGFR‐TKI beyond focal progression associated to microwave ablation is an efficacious therapeutic strategy.