Quantification of prostate cancer Gleason pattern 4 to predict oncological outcome

Area of Science:

• Urology
• Oncology
• Radiology

Background:

• Gleason Grade Group (GG) is standard for prostate cancer grading.
• Gleason pattern 4 (GP4) is a key component influencing prognosis.
• Accurate prediction of metastatic recurrence is crucial for treatment planning.

Purpose of the Study:

• To compare the predictive accuracy of GP4 quantification versus GG for metastatic recurrence after radical prostatectomy.
• To evaluate different GP4 quantification methods (percentage, millimeters, MRI-derived volume) using biopsy and MRI data.
• To assess the performance of GP4 quantification against established risk stratification tools.

Main Methods:

• Retrospective analysis of 446 patients undergoing MRI-guided biopsy and radical prostatectomy (2009-2018).
• Included patients with GG 2-4 disease without GP5.
• Compared predictors: biopsy GG, percentage GP4, millimeters GP4, MRI-derived GP4 volume, CAPRA, STAR-CAP, EAU, and NCCN risk scores.
• Evaluated predictive performance using the C-index.

Main Results:

• Preoperative GP4 volume estimation (C-index=0.80) demonstrated superior discrimination for metastatic recurrence compared to biopsy GG (C-index=0.70) and CAPRA score (C-index=0.72).
• Percentage GP4 (C-index=0.74) and millimeters GP4 (C-index=0.77) also outperformed standard risk scores.
• 46 patients developed any metastasis during a median follow-up of 6.9 years.

Conclusions:

• Preoperative GP4 volume estimation via MRI and targeted biopsy is superior to Gleason scoring and standard risk scores for predicting prostate cancer metastasis.
• GP4 quantification, particularly volume estimation, offers improved prognostic accuracy for patients with GG 2-4 prostate cancer.
• Further research is needed to optimize GP4 quantification methods for clinical integration into treatment decisions.