Hematologic variables associated with brain failure in patients with small-cell lung cancer.

Background and purpose: We sought factors associated with the development of brain metastases after treatment of small cell lung cancer (SCLC) in patients without brain involvement at diagnosis. Methods: We analyzed 293 patients with SCLC without brain metastases who received chemotherapy, thoracic radiation therapy (TRT), or both in 2001-2015. Pretreatment hematologic markers (platelet count, neutrophil count, lymphocyte count, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and lactate dehydrogenase) and other clinical characteristics were evaluated for correlation with brain metastases-free survival (BMFS). Cutoffs were established with receiver operating characteristics curves. Factors significant in univariate analysis were used to build a multivariate Cox model for BMFS. Results: Median follow-up time was 14.3 months. Brain metastases developed in 115 patients (39%)-32% of those with low pretreatment platelet counts (PPC) (<= 270 x 10(9)/L) and 46% of those with high PPC (>270 x 10(9)/L). Median BMFS time for all patients was 27.9 months. Two-year BMFS rates were worse for patients with high PPC (14.6% vs. 22.1% low, P = 0.009). High PPC was independently associated with inferior BMFS (P = 0.038), as were receipt of TRT <45 Gy and no prophylactic cranial irradiation (both P < 0.001). Conclusions: High PPC was associated with increased rates of brain metastasis in patients with SCLC with no evidence of brain disease at diagnosis. (C) 2018 Published by Elsevier B.V.