Dose‐escalated radiation therapy is associated with better overall survival in patients with bone metastases from solid tumors: a propensity score‐matched study

We aimed to compare the overall survival (OS) of patients with bone metastases (BM) from solid tumors after standard‐dose radiotherapy ([RT]; 30 Gy administered in 10 fractions; EQD(2Gy) = 32.5 Gy) and dose‐escalated RT (EQD(2Gy) > 32.5 Gy). We retrospectively reviewed the clinical charts of 1795 patients (median age, 62.3 years; age range, 18–96 years) with BM from solid tumors who were referred for RT to our institute between 2000 and 2013. These patients were assigned to the standard‐dose (n = 1125; 63%) and dose‐escalated (n = 670; 37%) RT groups. OS, estimated as the duration between the first RT session and death, served as the main outcome measure. The dose‐escalated RT group had a significantly better OS than the standard‐dose RT group (P = 0.000). After allowing potential confounders in multivariate analysis, the RT dose retained its independent association with OS (hazard ratio [HR], 0.837; 95% confidence interval [CI], 0.753–0.929, P = 0.001). After propensity score matching of the baseline characteristics of both groups, RT dose retained its independent association with OS (HR, 0.887; 95% CI, 0.737–0.951; P = 0.011) on multivariate analysis. Dose‐escalated RT exerted more favorable effects on OS in patients with non‐lung cancer, those without multiple metastases, those without symptoms, and those with favorable prognosis. Dose‐escalated RT was significantly associated with better OS in patients with BM from solid malignancies, particularly among those with non‐lung cancer, those without multiple metastases, those without symptoms, and those with favorable prognosis.