Additional radiation boost to whole brain radiation therapy may improve the survival of patients with brain metastases in small cell lung cancer

BACKGROUND: The role of the dose escalation strategy in brain radiotherapy for small cell lung cancer (SCLC) patients with brain metastases (BMs) has not been identified. This study aims to determine whether an additional radiation boost to whole brain radiation therapy (WBRT) has beneficial effects on overall survival (OS) compared with WBRT-alone. METHODS: A total of 82 SCLC patients who were found to have BMs treated with WBRT plus a radiation boost (n = 33) or WBRT-alone (n = 49) from January 2008 to December 2015 were retrospectively analyzed. All patients were limited-stage (LS) SCLC at the time of the initial diagnosis, and none of them had extracranial metastases prior to detection of BMs. The primary end point was OS. RESULTS: The median OS for all of the patients was 9.6 months and the 6-, 12- and 24-months OS rates were 69.1, 42.2 and 12.8%, respectively. At baseline, the proportion of more than 3 BMs was significantly higher in the WBRT group than in the WBRT plus boost group (p = 0.0001). WBRT plus a radiation boost was significantly associated with improved OS in these patients when compared with WBRT-alone (13.4 vs. 8.5 months; p = 0.004). Further, the survival benefit still remained significant in WBRT plus boost group among patients with 1 to 3 BMs (13.4 vs. 9.6 months; p = 0.022). CONCLUSION: Compared with WBRT-alone, the use of WBRT plus a radiation boost may prolong survival in SCLC patients with BMs. The dose escalation strategy in brain radiotherapy for selected BMs patients with SCLC should be considered.