Prostate cancer mortality rates in low- and favorable intermediate-risk active surveillance patients: a population-based competing risks analysis.

ABSTRACT

PURPOSE: To determine prostate cancer (PCa) and other-cause mortality rates in low- and favorable intermediate-risk (FIR) active surveillance (AS) patients. METHODS: The SEER Prostate with Watchful Waiting database was used to identify men diagnosed with NCCN low or FIR PCa, between 2010 and 2015, managed with AS. FIR patients were subdivided into three subgroups, based on their intermediate risk factor grade group two (GG2), PSA 10-20 ng/ml or cT2b-c disease. Cumulative incidence function curves with other-cause mortality as the competing risk were utilized. Predictors of PCa mortality were assessed using multivariable regression analysis with semi-parametric proportional hazards modeling. RESULTS: Among 70,871 patients, 48,127 (67.9%) had low and 22,744 (32.1%) had FIR disease. Median patient age was 64.0 years, and median PSA was 5.70 ng/ml. Median follow-up was 49.0 months. There were 166 (0.2%) PCa and 3,176 (4.48%) other-cause mortalities. The 5-year mortality rates in the low and FIR cohorts overall were 0.29% and 0.28%, respectively (p = 0.64). Within the FIR cohort, the corresponding rates were highest in the PSA 10-20 ng/ml subgroup at 0.73%, followed by 0.32% for GG2 FIR and 0.052% for cT2b-c FIR disease (p < 0.001). Older age at diagnosis (sHR 2.38, p = 0.006), Medicaid insurance (sHR 2.58, p < 0.001), low socioeconomic (sHR 1.39, p = 0.032), and non-married statuses (sHR 2.58, p < 0.001) were associated with increased PCa mortality. CONCLUSION: Intermediate-term PCa mortality rates in FIR PCa patients are non-significantly different to those with low-risk PCa. However, there is significant within-group heterogeneity, with PCa mortality rates significantly higher in the PSA 10-20 subgroup.