Over half of contemporary clinical Gleason 8 on prostate biopsy are downgraded at radical prostatectomy.

INTRODUCTION

Contemporary clinical guidelines utilize the highest Gleason sum (HGS) in any one core on prostate biopsy to determine prostate cancer treatment. Here, we present a large discrepancy between prostate cancer risk stratified as high risk on biopsy and their pathology after radical prostatectomy.

MATERIALS AND METHODS

We retrospectively reviewed 1424 men who underwent either open or robotic-assisted prostatectomy between 2004 and 2015. We analyzed 148 men who were diagnosed with HGS 8 on prostate biopsy. Biopsy and prostatectomy pathology were compared in aggregate and over 1 year time intervals. Chi-squared test, Fisher's exact test, Student's t-test, and Wilcoxon Rank-Sum test were used for statistical analysis.

RESULTS

A total of 61.5% (91/148) of clinical HGS 8 diagnoses were downgraded on prostatectomy, with 58.8% (87/148) downgraded to Gleason 7 (Gleason 4 + 3 n = 59; Gleason 3 + 4 n = 28). Factors associated with downgrading include lower prostate-specific antigen (PSA) at biopsy (median 6.8 ng/mL versus 9.1 ng/mL, p < 0.001), number of Gleason 8 biopsy cores (median 1 versus 2, p < 0.02), presence of Gleason pattern 3 on biopsy cores (67.9% versus 44.8%, p < 0.03), pT2 staging (72.4% versus 55.1%, p < 0.04), positive margins (53.9% versus 69.1%, p < 0.04), extracapsular extension (53.4% versus 74.1%, p < 0.02), and smaller percent tumor (median 10% versus 15%, p < 0.004).

CONCLUSION

The large percentage of pathology downgrading of biopsy-diagnosed HGS 8 suggests suboptimal risk-stratification that may lead to suboptimal treatment strategies and much patient distress. Our study adds great urgency to the efforts refining prostate cancer clinical assessment.