BACKGROUND:

The biggest challenge in treating prostate cancer, a cancer most frequently occurred in older men, is to detect accompanying geriatric problems (such as frailty) in these patients. However, a full geriatric assessment is time-consuming and not feasible in clinical practice. We thus adopted a previously developed multimorbidity frailty index (mFI) to do risk stratification of PCa patients and to evaluate the associations between mFI 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 primary treatment between 2011 and 2015 were identified. Frailty was measured using the 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. Patients in the severe frailty group had a significantly higher all-cause mortality risk than patients in the fit group (HR 1.38; 95% CI, 1.08–1.77), whereas there was no statistical significance in the mild frailty (HR 1.16; 95% CI, 0.95–1.42) and moderate frailty group (HR 0.98; 95% CI, 0.82–1.17) after adjustment. For cancer-specific mortality, frailty was not associated with the outcome.

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 all-cause mortality, but not cancer-specific mortality. Future studies should be conducted to see if management of frailty may improve all-cause mortality in PCa patients.