Effects of age and comorbidity on survival vary according to risk grouping among patients with prostate cancer treated using radical prostatectomy: A retrospective competing-risk analysis from the K-CaP registry

A multicenter Korean Prostate Cancer Database (K-CaP) has been established to provide information regarding Korean patients with prostate cancer (PCa). We used the K-CaP registry to investigate the value of age and comorbidity for predicting cancer-specific mortality (CSM) and other-cause mortality (OCM) according to risk grouping. The K-CaP registry includes 2253 patients who underwent radical prostatectomy (RP) between May 2001 and April 2013 at 5 institutions. Preoperative clinicopathologic data were collected and stratified according to the National Comprehensive Cancer Network risk criteria. Survival was evaluated using Gray's modified log-rank test according to risk category, age (<70 years vs ≥70 years), and Charlson comorbidity index (CCI) (0 vs ≥1). The median follow-up was 55.0 months (interquartile range: 42.0–70.0 months). Competing-risk regression analysis revealed that, independent of CCI, ≥70-year-old high-risk patients had significantly greater CSM than <70-year-old high-risk patients (P = .019). However, <70-year-old high-risk patients with a CCI of ≥1 had similar CSM relative to ≥70-year-old patients. Survival was not affected by age or CCI among low-risk or intermediate-risk patients. Multivariate analysis revealed that a CCI of ≥1 was independently associated with a higher risk of CSM (P = .003), while an age of ≥70 years was independently associated with a higher risk of OCM (P = .005). Age and comorbidity were associated with survival after RP among patients with high-risk PCa, although these associations were not observed among low-risk or intermediate-risk patients. Therefore, older patients with high-risk diseases and greater comorbidity may require alternative multidisciplinary treatment.