An easy tool to predict survival in patients with bone metastatic lung cancer treated with palliative radiotherapy

Abstract Background This study aimed to devise a simple assessment system for bone metastases (BMs) from lung cancer (LC). Methods A total of 368 LC patients with BMs who underwent radiotherapy (RT) were retrospectively reviewed. Prognostic factors were evaluated using multivariate analysis, and a scoring system based on regression coefficients was devised. Results The median follow‐up time for survival was 4.3 months, and the 0.5‐year overall survival (OS) rate was 44.7%. In the multivariate analysis, the significant prognostic factors were performance status (PS), metastases to internal organs, and post‐RT molecular‐targeting therapies (MTs) (tyrosine kinase inhibitors, and/or immune checkpoint inhibitors). A scoring system aggregating points assigned to each risk factor was created (2 points; non‐administration of post‐RT MTs, 1 point; PS ≥3 and metastases to internal organs). The median OSs were 25.0 months, 12.8 months, and 2.5 months in patients with a total score of 0 (n = 22), 1–2 (n = 124), and 3–4 (n = 221), respectively (p