Optimal Method for Reporting Prostate Cancer Grade in MRI-targeted Biopsies

Area of Science:

• Urologic Oncology
• Pathology Reporting
• Medical Imaging

Background:

• Assigning Gleason Grade Group (GG) for MRI-targeted prostate lesions can vary, using individual cores or aggregate data.
• Discrepancies in GG assignment may impact treatment decisions and patient outcomes.
• Optimal pathology reporting methods for MRI-targeted lesions require validation.

Purpose of the Study:

• To compare the concordance of biopsy Gleason Grade Group (GG) with radical prostatectomy (RP) GG for MRI-targeted lesions.
• To evaluate three methods of GG assignment: global (aggregate), highest, and largest volume core.
• To determine the most accurate method for pathology reporting of MRI-targeted prostate biopsies.

Main Methods:

• Retrospective analysis of 317 patients with 367 MRI-targeted lesions undergoing biopsy followed by radical prostatectomy (RP).
• Targeted lesion GG assigned using global (aggregated positive cores), highest GG (single core), and largest volume GG (longest cancer linear length).
• Comparison of biopsy GG with final RP GG using kappa (κ) and weighted kappa coefficients.

Main Results:

• Global GG showed the highest concordance with RP GG (73%, weighted κ: 0.77), followed by highest GG (68%, weighted κ: 0.79) and largest volume GG (62%, weighted κ: 0.71).
• When biopsy GG scores differed, global GG concordance with RP GG was 69% (weighted κ: 0.65), significantly higher than highest (52%, weighted κ: 0.68) or largest volume GG (31%, weighted κ: 0.59).
• Global GG demonstrated substantial agreement with RP-targeted lesion GG, outperforming other methods, especially when biopsy scores varied.

Conclusions:

• Global (aggregate) Gleason Grade Group assignment for MRI-targeted prostate biopsies shows superior agreement with radical prostatectomy findings.
• The global GG method is recommended for pathology reporting of MRI-targeted biopsies, offering more reliable grading.
• Further validation studies are warranted to solidify the clinical application of global GG reporting.