Risk factors which predict biopsy upgrading over time in active surveillance for prostate cancer.
290 Background: Active surveillance (AS) is recognized as the preferred treatment for low risk prostate cancer (PCa). No validated clinical tools currently exist to standardize the frequency of biopsies. We aimed to determine predictors of biopsy upgrading in a contemporary cohort of patients on AS. Methods: Men enrolled on AS at UCSF between 2000-2016 were included. The genomic tests used were Oncotype DX, Decipher and Prolaris. Biopsy upgrade was defined as ISUP grade group ≥ 2 on subsequent biopsy. PSA kinetics was calculated using a linear mixed-effects model for log of PSA, adjusted for clinical characteristics. Multivariable Cox proportional hazards regression models were utilized to identify factors associated with risk of upgrade on follow-up at first surveillance biopsy and at 3, 5 and 10 years. Results: 1,303 men were included. Upgrade-free survival at 3, 5 and 10 years was 73%, 53% and 27% respectively. Median time between diagnostic biopsy and first surveillance biopsy was 13 months (IQR 9-16) with the risk of upgrade at first surveillance biopsy associated with PSA density (hazard ratio [HR] 2.761, 95% confidence interval [CI] 1.895-4.023), and “high” risk genomic score (HR 1.867, 95% CI 1.025-3.401) on multivariable analysis after adjustments. Independent variables significantly associated with risk of upgrade at first surveillance biopsy and at 3, 5 and 10 years on multivariable analysis after adjustments are shown. Conclusions: Our findings suggest that genomic scores and PSA density are risk factors for biopsy upgrading within 3 years of starting AS, however PSA kinetics is associated with risk of upgrade at 5 and 10 years. When used in tandem, genomic scores may identify a subset eligible for AS who could potentially adopt a less intensive surveillance regimen.[Table: see text]