Palliative Performance Scale Predicts Survival in Patients with Bone Metastasis Undergoing Radiotherapy.

BACKGROUND: Accurate prognostication is essential for clinical decision-making in palliative radiotherapy (RT). The Palliative Performance Scale (PPS) is a validated tool for assessing functional status and estimating survival in palliative care, yet its prognostic value in patients receiving palliative RT for bone metastases remains insufficiently explored. This study aimed to evaluate the association between PPS and overall survival (OS) in a real-world cohort of cancer patients undergoing palliative RT. METHODS: This retrospective, single-center study included 153 patients who received palliative RT for bone metastases between 2021 and 2025 at the Department of Radiation Oncology, University Hospital Halle (Saale), Germany. Clinical, demographic, and treatment data were extracted from institutional databases. The primary endpoint was OS, defined as the time from the end of RT to death. Univariable and multivariable Cox proportional hazards regression models were used to identify prognostic factors associated with OS, including PPS, sex, age, marital status, BMI, Charlson Comorbidity Index (CCI), and RT completion. Due to violation of the proportional hazards assumption, PPS (<60% vs. ≥60%) was used as a stratification factor in the final Cox model. Logistic regression was performed to explore predictors of discharge to home. RESULTS: The median OS for the entire cohort was 108 days (3.6 months; 95% CI 78-143 days). Male sex (HR 1.61, 95% CI 1.06-2.46, p = 0.027) and older age (HR 0.98, 95% CI 0.96-1.00, p = 0.050) were associated with shorter survival, whereas completion of the prescribed RT course was strongly associated with improved OS (HR 0.06, 95% CI 0.03-0.12, p < 0.001). Patients with PPS ≥60% had significantly better survival compared to those with lower PPS (HR 0.62, 95% CI 0.41-0.93, p = 0.021). After stratification by PPS, no violation of the proportional hazards assumption was detected (global p = 0.55). The stratified model confirmed that male sex, age, and RT completion remained independent predictors of survival. No significant predictors were identified for discharge destination in logistic regression analysis. CONCLUSIONS: The PPS is a valuable prognostic tool for patients receiving palliative RT for bone metastases. A PPS of ≥60% was associated with prolonged survival, supporting its use in clinical prognostication and treatment planning. Completion of RT emerged as a strong independent predictor of survival, underscoring the importance of treatment adherence even in palliative settings. Stratification by PPS further improved model validity and prognostic accuracy.