Can We Omit Systematic Biopsies in Men with a Positive MRI During Repeat Biopsies for Active Surveillance for Prostate Cancer? Results from the PRIAS Study

Background and objective This study evaluated the added value of systematic biopsies (SBx) in addition to targeted biopsies (TBx) for detecting upgrading during repeat biopsies on active surveillance (AS) using data from the Prostate Cancer Research International Active Surveillance study. Methods We analyzed repeat biopsies of men who underwent magnetic resonance imaging (MRI) and SBx at diagnosis, with or without TBx depending on the presence of an MRI lesion, had at least one positive (Prostate Imaging Reporting and Data System 3–5) follow-up MRI, and received both SBx + TBx at subsequent repeat biopsy. Upgrading compared with diagnostic biopsy was assessed for TBx only, SBx only, and both, using three definitions: any upgrading, upgrading to grade group (GG) ≥2 with cribriform growth or intraductal carcinoma (≥GG2+), and upgrading to ≥GG3. Cumulative incidences were calculated using each detection method as competing events. For upgrading ≥GG2+ detected by SBx only, the laterality relative to the MRI lesion was determined. Key findings and limitations We analyzed 650 repeat biopsies in 568 patients with a median follow-up of 3.0 yr (interquartile range = 1.8–4.3) for men still on AS. During available follow-up, any upgrading occurred in 238 biopsies (37%), of which 47 (7.2%) were detected by SBx only. Upgrading to ≥GG2+ and ≥GG3 was observed in 100 biopsies (16%) and 78 biopsies (12%), respectively, with SBx alone identifying 19 (3.0%) and 15 (2.3%) of these patients. At 6 yr, the cumulative incidence of ≥GG2+ upgrading was 27% (95% confidence interval [CI] = 21–32%), with 5.4% (95% CI = 2.9–9.1%) for upgrading detected exclusively by SBx. Three of the 19 cases with upgrading to ≥GG2+ detected by SBx only were located contralateral to the MRI lesion (0.5% of all biopsies). Limitations include the retrospective design, which may introduce selection and registration biases. Conclusions and clinical implications In men on AS who underwent diagnostic MRI with SBx (with or without TBx) and a positive follow-up MRI, SBx has limited added value during repeat biopsies, particularly for contralateral sampling, supporting a targeted and perilesional biopsy approach.