Validation of a novel prognostic index: BMS-Score for patients with brain metastases of small cell lung cancer

Background: A new disease-specific prognostic score (Disease-specific Prognostic Score for Patients With Brain Metastases From Small-cell Lung Cancer termed BMS-Score) was published to clarify the prognosis of patients with brain metastasis (BM) of small cell lung cancer (SCLC) treated with whole brain radiotherapy (WBRT). The purpose of the present study was to validate the prognostic value of the newly proposed BMS-Score through comparison with three other previously published prognostic indices. Methods: In total, 451 patients with BM of SCLC treated with WBRT at the Shanxi Province Cancer Hospital from January 2010 to December 2019 were included. The clinical characteristics of all patients were recorded and follow-up was through April 2020. Overall survival (OS) was calculated by Kaplan-Meier analysis, and univariate and multivariate analyses were used to calculate the prognostic cofactors. The concordance index (C-index) was used to assess the prognostic value of the following four prognostic systems: recursive partitioning analysis (RPA), diagnosis-specific graded prognostic assessment (DS-GPA), basic score for brain metastases (BSBM), and the newly proposed BMS-Score. Results: The independent factors affecting the prognosis of SCLC patients with BM included the Karnofsky performance score (KPS), number of brain metastases, extracranial metastases (ECM) state, and whether treatment had been received before BM. RPA, BSBM, DS-GPA, and BMS-Score log-rank test P values were all less than 0.001 among each group (P<0.001). The C-indices of the four groups were 0.554, 0.584, 0.588, and 0.643, respectively. Conclusions: The four prognostic scoring systems exhibited medium predictive value for SCLC. The BMS-Score had the best applicability compared with the other three prognosis indices.