Impact of Frailty on Survivals of Prostate Cancer Patients Treated with Radiotherapy

BACKGROUND: : Frailty has been linked to an increased risk of adverse outcomes among older men with prostate cancer (PCa), which in turn impacts survival. We evaluated the associations between frailty and risks of all-cause mortality and cancer-specific mortality in PCa patients treated with radiotherapy (RT). METHODS: : We conducted a retrospective cohort study using the Taiwan Cancer Registry Database and National Health Insurance Research Database. Patients aged ≥65 years with newly-diagnosed PCa, and receiving RT as initial treatment between 2011 and 2015 were identified in the study. Frailty was measured using the multimorbidity frailty index (mFI), categorized as fit, mild frailty, moderate frailty, and severe frailty. Cox regression models were used to examine the association between frailty and mortality. RESULTS: : Among 4,291 men with a median age of 75 years at PCa diagnosis, 21.87% were categorized as fit, 44.72% were mild frailty, 23.02% were moderate frailty, and 10.42% were severe frailty. With the mean follow-up duration of 4.8 years, patients in the severe frailty group had a significantly higher all-cause mortality risk (HR 1.86; 95% CI, 1.48–2.32) and cancer-specific mortality risk (HR 1.44; 95% CI, 1.05–1.98) than patients in the fit group, whereas no such association was found in the mild frailty group after adjustment. CONCLUSIONS: : This is the first population-based cohort study to evaluate the feasibility of mFI on mortality of PCa patients treated with RT. We found that severe frailty was associated with a higher risk of both all-cause mortality and cancer-specific mortality.