Risk Group and Death From Prostate Cancer Implications for Active Surveillance in Men With Favorable Intermediate-Risk Prostate Cancer

IMPORTANCE Active surveillance (AS), per the National Comprehensive Cancer Network (NCCN) guidelines, is considered for patients with low-risk prostate cancer (PC) and a life expectancy of at least 10 years. However, given the grade migration following the 2005 International Society of Urologic Pathology consensus conference, AS may be appropriate for men presenting with favorable intermediate-risk PC. OBJECTIVE To estimate and compare the risk of PC-specific mortality (PCSM) and all-cause mortality (ACM) following brachytherapy among men with low and favorable intermediate-risk PC. DESIGN, SETTING, AND PARTICIPANTS Prospective cohort study of 5580 consecutively treated men (median age, 68 years) with localized adenocarcinoma of the prostate treated with brachytherapy at the Prostate Cancer Foundation of Chicago between October 16, 1997, and May 28, 2013. INTERVENTION Standard of practice per the NCCN guidelines. MAIN OUTCOMES AND MEASURES Fine and Gray competing risks regression and Cox regression analyses were used to assess whether the risks of PCSM and ACM, respectively, were increased in men with favorable intermediate-risk vs low-risk PC. Analyses were adjusted for age at brachytherapy, year of treatment, and known PC prognostic factors. RESULTS After median follow-up of 7.69 years, 605 men had died (10.84% of total cohort), 34 of PC (5.62% of total deaths). Men with favorable intermediate-risk PC did not have significantly increased risk of PCSM and ACM compared with men with low-risk PC (adjusted hazard ratio [HR], 1.64; 95% CI, 0.76-3.53; P=.21 for PCSM; adjusted HR, 1.11; 95% CI, 0.88-1.39; P=.38 for ACM). Eight-year adjusted point estimates for PCSM were low: 0.48% (95% CI, 0.23%-0.93%) and 0.33%(95% CI, 0.19%-0.56%) for men with favorable intermediate-risk PC and low-risk PC, respectively. The respective estimates for ACM were 10.45%(95% CI, 8.91%-12.12%) and 8.68%(95% CI, 7.80%-9.61%). CONCLUSIONS AND RELEVANCE Men with low-risk PC and favorable intermediate-risk PC have similarly low estimates of PCSM and ACM during the first decade following brachytherapy. While awaiting the results of ProtecT, the randomized trial of AS vs treatment, our results provide evidence to support AS as an initial approach for men with favorable intermediate-risk PC.