Advanced age increases cancer-specific mortality in bone-only metastatic prostate cancer: a SEER analysis

The prognostic impact of age in bone-only metastatic prostate cancer (BoM-PCa) remains insufficiently characterized. This study evaluated the association between age and cancer-specific mortality (CSM) in a population-based cohort. Men diagnosed with BoM-PCa between 2010 and 2022 were identified from the SEER database. Cumulative incidence functions were generated, and Fine-Gray competing-risk regression was used to assess independent predictors of CSM. A total of 11,098 patients, 48.2% of whom were aged ≥ 70 years, were included. Five-year CSM increased stepwise with advancing age (50.2% in patients < 50 years vs. 64.8% in those ≥ 80; p < 0.001). At multivariate analysis, older age remained independently associated with higher CSM (≥ 80 years: subdistribution hazard ratio 1.78, 95% CI 1.45-2.19). Non-Hispanic Black race/ethnicity, single marital status, elevated prostate-specific antigen, and a higher International Society of Urological Pathology (ISUP) grade emerged as adverse predictors. Radical prostatectomy was associated with lower CSM, while radiotherapy and chemotherapy were associated with higher CSM in the overall cohort. Prostate-specific antigen and ISUP grade remained strong independent predictors in patients ≥ 70 years. Advancing age independently predicts higher CSM in BoM-PCa. Tumor burden, pathological grade, and treatment allocation jointly affect age-related survival disparities.