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Morphologic patterns observed in prostate biopsy cases with discrepant grade group and molecular risk classification

  • 0Department of Pathology, University of California, San Francisco, San Francisco, California, USA.
The Prostate +

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May 12, 2024

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May 12, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

Discrepancies between Gleason Grade Group (GG) and Decipher prostate cancer risk scores were analyzed. Difficult-to-grade patterns were common in low-GG/high-Decipher cases, while aggressive features appeared in high-GG/low-Decipher cases.

Area Of Science

  • Urology
  • Oncology
  • Pathology

Background

  • Molecular-based risk classifiers like the Decipher prostate biopsy test are increasingly used to guide treatment decisions.
  • The Decipher test is a 22-gene RNA assay predicting high-grade disease, metastasis, and mortality risk, categorized as low, intermediate, or high.
  • This study investigates histologic features in prostate biopsies where the Grade Group (GG) and Decipher risk category were discordant.

Purpose Of The Study

  • To examine the histologic characteristics of prostate biopsies with discordant Grade Group (GG) and Decipher molecular risk categories.
  • To identify potential reasons for discrepancies between traditional histologic grading and molecular risk assessment.

Main Methods

  • A retrospective review of 178 men with prostate biopsies and Decipher testing (2016-2020) was conducted.
  • Discrepancies were defined as GG1-2 with high Decipher risk or GG≥3 with low Decipher risk.
  • Biopsy slides were re-reviewed for GG and specific histologic features, including Gleason patterns, high-risk features (e.g., IDC), and difficult-to-grade patterns.

Main Results

  • Of 178 men, 41 (23%) had discordant GG and Decipher risk; 33 slides were reviewed.
  • Among these, 23 had GG1-2 with high Decipher risk, often showing difficult-to-grade patterns (e.g., atrophic carcinoma, collagenous fibroplasia).
  • Ten had GG≥3 with low Decipher risk, with half exhibiting aggressive histologic patterns like large cribriform or intraductal carcinoma (IDC).

Conclusions

  • Difficult-to-grade patterns are frequently observed in GG1-2 cases with high Decipher risk, suggesting potential underestimation of risk by histology alone.
  • Aggressive histologic patterns were present in half of GG≥3 cases with low Decipher risk, indicating that molecular classifiers may not encompass all high-risk histologic features.

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