Radiation boost does not help whole-brain radiotherapy further improve survivals of SCLC brain metastasis patients

Abstract

Objective To investigate the effect of radiation boost (Boost) on further improving overall survival (OS) and intracranial progression-free survival (IPFS) of small-cell lung cancer (SCLC) brain metastases (BM) patients treated by whole-brain radiotherapy (WBRT). Methods A retrospective analysis of 142 consecutive SCLC BM patients admitted between 2013 and 2015 was conducted after excluding those with historical prophylactic cranial irradiation (n=16) or SRT (n=10) or local RT alone (n=1). The Kaplan-Meier curve was utilized to calculate the survival rate. The log-rank test and multivariate Cox proportional hazard regression model were utilized to evaluate clinical prognosis. Results All patients were aged 59.6 years old on average, and the female proportion was 23%. The quantity of brain metastasis lesion was 1 in 35%, 2-3 in 23% and ≥4 in 42%, respectively. The proportion of patients receiving chemotherapy was 70%. The median OS was 9.0 months and the median IPFS was 7.3 months. The accumulative mortality rate in the non-radiation (n=53), WBRT (n=33) and WBRT+ Boost (n=56) groups was 92%, 79% and 73%, and the accumulative failure rate (death or new/relapsed brain metastasis) was 94%, 82% and 80%, respectively. Compared with the non-radiation group, WBRT and WBRT+ Boost therapies exerted significant effect upon OS (P=0.000 and 0.000) and IPFS (P=0.000 and 0.000). Compared with WBRT alone, WBRT+ Boost treatment exerted no significant effect upon OS (P=0.41 and 0.51). Conclusions WBRT can significantly improve OS and IPFS of patients with SCLC-BM. However, concurrent and additional radiation boost does not further improve the survival rate. Key words: Brain metastasis, small-cell lung cancer/whole-brain radiotherapy; Prognosis