Independent Validation of a Risk Stratification Model Predicting Survival in Elderly Patients Irradiated for Bone Metastases

Abstract

Background/Aim: The aim of this study was to analyze the validity of a prognostic model, originally developed by Rades et al., because international variations in clinical practice and survival outcomes may impact on the performance of predictive tools. Materials and Methods: Retrospectively, data from a single institution were analyzed. The study included 305 patients managed with palliative radiotherapy for bone metastases. The Rades et al. score was assigned and the resulting 3 prognostic strata compared. Results: The median overall survival for the 3 strata was 48, 248 and 1065 days, respectively (p<0.001). However, the original break-down (17 points versus 18-25 points versus >25 points) was not in accordance with the overlapping survival curves in some of the subgroups, leading us to propose slight adjustments. The modified model also performed satisfactorily in the oldest patients (age ≥80 years; median survival 26, 192 and 489 days, respectively, p<0.001). Conclusion: The original Rades et al. score is a valid prognostic model in our Norwegian validation database. However, modification is suggested, in particular inclusion of patients with 18 points into the poor prognosis group..