Introduction: We assessed the accuracy of transrectal saturation prostate biopsy compared to extended prostate biopsy in patients on active surveillance. Determining prostate cancer aggressiveness is mandatory to determine appropriate candidates for active surveillance and appropriateness to remain on active surveillance protocols.
Methods: From our institutional review board approved database we reviewed the biopsies of 277 patients diagnosed with prostate cancer on an active surveillance protocol. Eligibility criteria included clinical stage T1 to T2a, Gleason score 6 or less, prostate specific antigen 10 ng/ml or less and percent of positive cores 33% or less of the total cores taken on diagnostic biopsy. We defined recategorization or pathological progression on first confirmatory and surveillance biopsies as no longer meeting the standard definition of low risk by cancer volume or Gleason score criteria.
Results: Of 444 biopsies 279 were extended prostate biopsy (10 to 14 cores) and 165 were saturation prostate biopsy (20 cores or greater). The rate of cancer recategorization (reclassification) was highest on the first confirmatory biopsy at 25%. There was no significant difference between extended and saturation prostate biopsy for detecting recategorization on the first confirmatory biopsy (21.5% vs 29.4%, p = 0.13). Saturation prostate biopsy was significantly more likely to detect cancer progression on all subsequent surveillance biopsies.
Conclusions: Disease progression or recategorization was more frequently identified on the first confirmatory biopsy than on subsequent surveillance biopsies. The incidence of disease recategorization was higher in the saturation biopsy group than in the extended biopsy group on the first confirmatory biopsy but the difference was not statistically significant. Disease progression was more likely to be identified by saturation prostate biopsy on subsequent surveillance biopsies.
Keywords: biopsy; disease progression; prostate; prostatic neoplasms; risk.