Impact of Different Timing of Radiation Therapy on Patients With Brain Metastases from Epidermal Growth Factor Receptor-Mutant Non–small Cell Lung Cancer

Abstract

To perform a retrospective analysis of patients with brain metastases (BM) from epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) to evaluate the preferred treatment timing of EGFR-tyrosine kinase inhibitors (TKIs) in this population. Of 94 initial or recurrent patients diagnosed BM from EGFR-mutant NSCLC between Jan 1, 2012, and Jun 31, 2016, 30 received upfront brain RT followed by EGFR-TKI, 39 EGFR-TKI combined with concurrent brain RT, and 25 upfront EGFR-TKI then brain RT. Disease-specific-graded prognostic assessment was similar among all 3 groups. The primary endpoint was overall survival (OS), and the second endpoint was intracranial progression-free survival. Although the median OS was not significantly different among the upfront RT, concurrent treatment, and upfront EGFR-TKI groups (29.0 vs 24.0 vs 17.0 months; P=0.186), however, it was longer in the upfront RT group compared with the upfront EGFR-TKI group (P=0.035). On subgroup analysis, the exon 19 deletions patients had longer OS than the exon 21 mutations patients in upfront EGFR-TKI group (23.0 vs 15.0 months; P=0.048), but the upfront RT (34.0 vs 23.0 months; P=0.186) and the concurrent treatment groups (24.0 vs 13.0 months; P=0.827) did not. According to multivariate COX analysis, KPS (≥ 70) and intracranial metastasis alone was associated with a longer OS. The median intracranial progression-free survival was significantly improved in patients receiving upfront RT compared with those receiving concurrent treatment or upfront EGFR-TKI (not reached vs 40.0 vs 9.0 months; P=0.003). The present study suggests that the use of upfront brain radiotherapy, and the deferral of EGFR-TKI may result in superior OS in patients with brain metastases from EGFR-mutant NSCLC. Also, upfront brain radiotherapy management could significantly reduce the risk of intracranial progression. A prospective, multi-institutional, randomized trial of upfront EGFR-TKI then RT versus upfront RT followed by EGFR-TKI is urgently needed, especially based on different subgroup population.