Intracranial control and survival outcome of tyrosine kinase inhibitor (TKI) alone versus TKI plus radiotherapy for brain metastasis of epidermal growth factor receptor-mutant non-small cell lung cancer.

INTRODUCTION: The efficacy of tyrosine kinase inhibitors (TKIs) with and without radiotherapy (RT) has not been determined in patients with brain metastases from epidermal growth factor receptor-mutant TKI naïve non-small cell lung cancer (NSCLC).

METHODS: Between 2008 and 2016, 586 patients were diagnosed with NSCLC and treated with TKIs at a hospital in Seoul, South Korea; 81 of these patients met the eligibility criteria for our study. Outcomes analyzed included intracranial progression (ICP), neurological death, and overall survival (OS).

RESULTS: The 2-year cumulative incidence of ICP was 36.5% in the TKI plus RT group and 62.2% in the TKI alone group (P = 0.006). The chronological pattern analysis indicated that 64.3% of ICP developed within 12 months of the start of TKI treatment in the TKI alone group. The multivariate analysis revealed that treatment group (P = 0.003) and duration of TKI treatment ≤ 12 months (P < 0.001) were significantly associated with ICP. However, no significant differences were observed in the 2-year OS rate (P = 0.267) or the 2-year cumulative incidence of neurological death (P = 0.740).

CONCLUSIONS: Cumulative incidence of ICP was significantly lower with TKI plus RT than with TKI alone; however, there was no significant difference in OS or neurological death. Deferring brain RT may not compromise neurologic and survival outcome in selected patients, but close magnetic resonance imaging follow-up is recommended for patients who defer brain RT.