Prognostic Models for Patient Selection in Palliative Bone Radiotherapy: A Systematic Review

Palliative radiotherapy is a well-established treatment for symptomatic bone metastases, but patients with a vital prognosis of under 3 months may not experience benefit, making accurate prognostic estimation essential for treatment selection. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review of PubMed, Scopus, and Web of Science identified studies evaluating prognostic models in patients receiving bone metastases palliative radiotherapy. The risk of bias was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). Nineteen studies were included, most retrospective and heterogeneous, with mixed primary tumour histology. A broad range of prognostic approaches was identified, including established scores, newly developed prognostic tools, validated models, and individual prognostic factors. Performance status was the strongest prognostic variable. Models found were heterogeneous, and most studies had a high or unclear risk of bias. This PRISMA review highlights that prognostic models may support patient selection for palliative radiotherapy, but given the heterogeneity of patients and clinical settings, their use requires robust external validation and should be adequate to the local context, clinician experience, and patient characteristics.