Serum lactate dehydrogenase predicts survival in small-cell lung cancer patients with brain metastases that were treated with whole-brain radiotherapy.

This study aimed to identify factors that predict prognosis after radiotherapy for brain metastases (BMs) from small-cell lung cancer (SCLC). This study retrospectively evaluated 48 consecutive patients who underwent whole-brain radiotherapy (WBRT) for BMs from SCLC between February 2008 and December 2017. WBRT was delivered at a median dose of 30 Gy (range: 30-40 Gy) in 10 fractions (range: 10-16 fractions). Clinical factors were tested for associations with overall survival after WBRT. The median survival and 1-year overall survival rate after WBRT treatment were 232 days and 34.4%, respectively. Univariate analyses revealed that longer survival was associated with Eastern Cooperative Oncology Group performance status of 0-1, asymptomatic BMs, lactate dehydrogenase (LDH) in the normal range, Radiation Therapy Oncology Group-recursive partitioning analysis class 2, and a graded prognostic assessment score of ≥1.5 (P < 0.01, P < 0.01, P < 0.01, P < 0.01 and P < 0.05, respectively). In the multivariate analyses, longer survival was independently associated with asymptomatic BMs [hazard ratio for death (HR), 0.32; 95% confidence interval (CI), 0.12-0.79; P < 0.05] and LDH in the normal range (HR, 0.42; 95% CI, 0.21-0.83; P < 0.05). The presence of symptoms due to BMs and LDH values independently predicted prognosis after WBRT for BMs from SCLC. Elevated LDH may provide valuable information for identifying patients with BMs who could have poor survival outcomes.