408P - Whole brain radiotherapy plus simultaneous in-field boost versus whole brain radiotherapy plus fractionated stereotactic radiotherapy for multiple brain metastases of non-small cell lung cancer

Abstract

BackgroundBrain metastasis (BM) is common among patients with non-small cell lung cancer (NSCLC). Whole brain radiotherapy (WBRT) plus a radiation boost is a common treatment strategy for such patients. WBRT plus simultaneous in-field boost (WBRT+SIB) and WBRT plus hypo-fractionated stereotactic radiotherapy (WBRT+FSRT) have shown promising outcomes. The current study compared the efficacy and safety of these two treatment strategies. MethodsSixty-six NSCLC patients with multiple BMs who met the inclusion criteria from January 2010 to December 2016 were enrolled. The efficacy and toxicity of WBRT+SIB and WBRT+FSRT were analyzed retrospectively. A Cox proportional hazard model was used to identify prognostic factors. ResultsThe objective response rates in the WBRT+SIB and WBRT+FSRT groups were similar (74.9% and 79.4%, respectively; p=0.5), as was the disease control rate (93.8% and 97.1%, respectively; P=0.3). The median survival time was 15.3 months in the WBRT+SIB group and 25.2 months in the WBRT+FSRT group (p=0.02). The median local progression-free survival was 13 months in the WBRT+SIB group and 17 months in the WBRT+FSRT group (p=0.04). The incidence of 1-3 grade toxicity was slightly lower in the WBRT+FSRT group than the WBRT+SIB group (31.2% vs. 38.2%). Compared to the WBRT+SIB group, the WBRT+FSRT group was associated with a lower risk of mortality (HR=0.6; 95% CI, 0.1-0.7) in the Cox multivariate model. Extracranial metastases, worse recursive partitioning analysis class, and non-surgical treatment of primary lesions were associated with a worse prognosis. ConclusionsCompared to WBRT+SIB, WBRT+FSRT treatment was associated with a better prognosis and slightly less toxicity in patients with multiple BMs from NSCLC. Further studies are warranted to better elucidate the difference and determine the optimal dose/fractionation. Legal entity responsible for the studyJinyi Lang. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.