Predictors of Unfavourable Repeat Biopsy Results in Men Participating in a Prospective Active Surveillance Program

BackgroundActive surveillance (AS) protocols for low-risk prostate cancer (PCa) generally include repeat prostate biopsies at predefined follow-up intervals.ObjectiveTo study the outcome of routinely obtained 1-yr repeat biopsies and factors predicting reclassification to higher risk, to contribute to risk stratification for men on AS.Design, setting, and participantsWe analysed men with low-risk PCa (clinical stage ≤T2, prostate-specific antigen (PSA) ≤10 ng/ml, PSA density <0.2 ng/ml per millilitre, one or two positive biopsy cores, and Gleason score ≤6) who had been included in a prospective AS protocol.InterventionsPSA was measured 3-monthly and the first volume-dependent repeat biopsy was scheduled 1 yr after diagnosis, independent of PSA doubling time (PSA-DT). Reclassification to higher risk disease on repeat biopsy was defined as Gleason score ≥7 or ≥3 positive cores.MeasurementsWe analysed whether baseline patient characteristics and PSA-DT were associated with reclassification to more aggressive PCa on repeat biopsy.Results and limitationsA first repeat biopsy was taken in 757 patients after median follow-up of 1.03 yr. The results of repeat biopsies were favourable (no or low-risk PCa) in 594 patients (78.5%) and led to reclassification of risk in 163 (21.5%). Analysis showed that reclassification to higher risk was significantly influenced by the number of initial positive cores (two vs one) (odds ratio [OR]: 1.8; p = 0.002) and higher PSA density (OR: 2.1; p = 0.003). The outcome was not significantly influenced by age, clinical stage, total number of biopsy cores, or PSA. Adding PSA-DT at time of repeat biopsy to the model showed PSA-DT <3 yr to be significantly associated with reclassification to higher risk (OR: 1.7; p = 0.015). Data on tumour involvement per biopsy core were not available.ConclusionsClinical features at baseline and during follow-up in our AS cohort are significantly associated with short-term reclassification to higher risk on repeat biopsy. These characteristics can potentially be used for risk stratification of men with PCa who are apparently at favourable risk.Trial registrationThe current program is registered at the Dutch Trial Register with identification number ID NTR1718 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1718).