Abstract / Summary
Purpose: Although the individual prognostic value of performance status (PS) and prescribed dose for overall survival (OS) in palliative radiation therapy for bone metastases has been investigated, their combined prognostic significance has not been thoroughly explored. This study aimed to evaluate the combined prognostic value of PS and prescribed dose for OS in patients with bone metastases undergoing palliative radiation therapy. Methods and Materials: This study included 423 patients who underwent palliative radiation therapy for bone metastases between January 2013 and October 2024. The primary endpoint was OS, evaluated at fixed follow-up points of 1, 3, and 6 months, as well as 1, 2, and 3 years. Results: Univariate Cox regression analysis demonstrated that 1-year OS was significantly associated with poor PS (hazard ratio, 2.6 [95% CI, 2.2-3.1]; P < .001) and a lower prescribed dose (<39 Gy in a biologically effective dose with α/β = 10; hazard ratio, 3.9 [95% CI, 2.8-5.3]; P < .001), both of which remained independent predictors of worse OS in multivariate analysis (both P < .001). Comparison of the areas under the curves showed that adding prescribed dose to PS significantly improved the predictive accuracy of OS at 1 and 3 months (both P < .001), 6 months ( P = .002), 1 year ( P = .028), and 2 years ( P = .032). However, the improvement was not statistically significant at 3 years ( P = .086). Kaplan–Meier curve analysis with log-rank tests showed that combining PS and prescribed dose improved OS risk stratification ( P < .001 for all follow-up periods), regardless of primary tumor risk or the number of distant metastases. Conclusions: Combining PS and prescribed dose enabled more refined risk stratification for predicting short- and long-term OS in patients with bone metastases undergoing palliative radiation therapy, regardless of primary tumor risk classification or the number of distant metastases. Moreover, adding prescribed dose to PS provided significant incremental predictive value for OS in this setting.