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.