Predictors of prognosis of synchronous brain metastases in small-cell lung cancer patients

Patients with small cell lung cancer (SCLC) are more likely to have synchronous brain metastasis (SBM) at the time of diagnosis than patients with any other extracranial primary malignancy. We sought to identify which factors predicted an increased risk of SBM in SCLC as well as which factors affected the prognosis of these patients. 38,956 Patients in the Surveillance, Epidemiology, and End Results (SEER) database with microscopically confirmed SCLC from 2010 to 2016 were identified. 6264 (16.1%) Patients with SCLC had SBM at the time of diagnosis. In the multivariable logistic regression, disease specific factors that were predictive of SBM were primary tumor size > 7 cm (adjusted OR = 1.14, 95% CI [1.02, 1.28], p = 0.02), synchronous lung metastases, and synchronous bone metastases. Demographic specific factors predictive of increased SBM risk in this model were younger age, male sex, and race (American Indian/Alaska Native and black patients). Patients insured through Medicaid were less likely to present with SBM. In the multivariate Cox proportional hazards model, lack of insurance was the strongest predictor of mortality (adjusted HR = 1.47, 95% CI [1.26, 1.73], p < 0.001). Other factors associated with an increased risk of mortality include male sex, older age, health insurance coverage through Medicaid, synchronous liver metastasis, synchronous lung metastasis, and primary tumor size > 7 cm. In contrast, Asian patients had a lower risk of mortality. This study identifies risk factors for SBM among patients with SCLC, as well as indicators of prognosis among this patient population.