Evaluation of a Limited Number of Histologic Levels in Prostate Needle Core Biopsies: Do Clinically Significant Cancer Parameters Go Undetected?

IntroductionIn the era of increasing prostate needle core biopsy (PNCB) burden with extended core and MRI-guided biopsies, recommendations are limited on how many histologic levels are needed to identify prostate cancer parameters. Many institutions, including ours, have utilized up to 6 levels. Our quality improvement study evaluates undetected prostate cancer parameters and cost/time savings when reducing to 3 levels.MethodsFifty-eight PNCB series (204 individual PNCB) with prostate cancer were identified from 74 consecutive series (614 individual PNCB). Six levels placed on 2 slides were reviewed. Detection of prostate cancer, secondary Gleason patterns, extraprostatic extension, perineural invasion, and atypical small acinar proliferation (ASAP) were compared between the original 6 levels and a simulated reduction to 3 levels using 3 methods: 1) 3-level spanning most of the tissue block, 2) 3-level spanning the superficial block, and 3) 3-level spanning the deep block. Laboratory costs and microtomy/embedding time data were analyzed to determine savings following change to a 3-level protocol.ResultsThe simulated 3-level method spanning most of the block identified all cancer foci and parameters originally detected with 6 levels, except one focus of ASAP (N = 13). Small cancer foci (< 1 mm) and associated parameters were occasionally undetected when only 3 superficial or deep levels were reviewed. Switching to a 3-level cutting protocol saved $9134 over 6 months and reduced microtomy/embedding time by 9.7 min per 12-part PNCB series.ConclusionAt our institution, evaluating 3 levels spanning most of the block conserves resources while adequately detecting prostate cancer parameters.