Factors associated with biopsy progression on active surveillance.

Abstract

19 Background: Active surveillance (AS) is a treatment strategy for prostate cancer (CaP) involving monitoring of men diagnosed with low-risk CaP to reduce overtreatment. We report factors associated with disease progression while on AS in a large, single institution cohort. Methods: We retrospectively reviewed the data of men enrolled in the University of California at San Francisco (UCSF) AS cohort between 1990 and 2012. Strict eligibility criteria were prostate-specific antigen (PSA) less than 10ng/ml, Stage less than cT3, Gleason grade 6 or less, 33% or less of biopsy cores positive, and 50% or less of any single biopsy core positive. Men who did not meet these criteria but elected AS were followed as well. Surveillance consisted of quarterly PSA testing, reimaging with TRUS at provider discretion, and annual prostate biopsy. Biopsy progression was defined as upgrade to at least Gleason 7 or increase in volume more than 33% cores. Factors associated with progression while on active surveillance were determined through multivariate Cox proportional hazards regression. Results: Of 1,009 men enrolled in AS at UCSF, 758 men have consented to participate in research to date and have been followed on AS for a median of 57 months. Of these, 518 (68%) met strict criteria for AS while 240 (32%) did not. The median number of repeat biopsies was three (IQR 2-4). At 5 years after diagnosis, 53% were progression-free and 40% of patients received local therapy. Overall survival was 94% among those not AS eligible and 100% among those AS eligible at 5 years. There were no CaP-related deaths. In multivariate analysis, only PSA density (PSAD) and later year of diagnosis were positively associated with the risk of both biopsy progression (HR 1.62, 95% CI 1.36-1.92, p<0.01 and HR 1.17, 95% CI 1.10-1.25, p<0.01, respectively) and receiving treatment (HR 1.39, 95% CI 1.20-1.60, p<0.01 and HR 1.18, 95% CI 1.14-1.23, p<0.01, respectively). White race was associated with receiving treatment (HR 1.92, 95% CI 1.35-2.74, p<0.01) but not with disease progression. Conclusions: The majority of men who enrolled in this active surveillance cohort remained on AS after a median follow up of 57 months. While higher PSAD was associated with biopsy progression, additional predictive tools would improve selection and counseling of men for AS.