Purpose of review: The present review describes recent changes in the histologic grading of prostatic adenocarcinoma and emerging data suggesting areas for further grade optimization.
Recent findings: The grading of prostatic adenocarcinoma has evolved over time, and optimization for active surveillance management has been one major driving force. Recent changes include adoption of the Grade Group system, which stratifies patients into one of five prognostic groups. Although it provides clearer labels for patient understanding and defines a more homogenous low-risk group (i.e. Grade Group 1 of 5), emerging data suggest that further prognostic stratification may be achieved by incorporating other histologic findings. The impact of 'cribriform histology' and intraductal carcinoma as aggressive features of prostate cancer has gained significant recognition. Furthermore, quantifying the fraction of each individual Gleason pattern component may also add prognostic stratification. In addition to Gleason score and Grade Group, some institutions now identify and report high-risk histologic patterns (e.g. 'cribriform histology') and the percentage of Gleason pattern 4 on biopsies. While early in adoption, these additional features are being used to further stratify patients beyond the Grade Group system, particularly for patients with Grade Group 2 carcinomas. These histologic findings will likely be incorporated into future modifications of the grading system to further optimize patient stratification and ensure reporting consistency.
Summary: The histologic evaluation of prostatic adenocarcinoma provides strong prognostic information for clinical management. The recent Grade Group system offers many improvements, but further optimization based on specific histologic patterns may evolve.