Login to Access Video or Poster Abstract: MP33-18
Sources of Funding: none

Introduction

Accurate biopsy Gleason scoring is critical for the proper treatment of prostate cancer (PC). Here, we present an alarming discrepancy between PC diagnosed as high-risk pathology on biopsy and their actual pathology after radical prostatectomy (RP).

Methods

We retrospectively reviewed 1034 men who underwent open RP by a single surgeon between 2004 and 2015. 112 men were diagnosed with Gleason 8 pathology on prostate biopsy. We excluded 5 patients whose RPs were aborted and 4 whose neoadjuvant treatments prevented proper Gleason scoring. Biopsy and RP pathology were compared in aggregate and over one-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

61.1% (63/103) of clinical Gleason 8 diagnoses were downgraded on surgical pathology after RP, with 60 specimens being downgraded to Gleason 7 (Gleason 4+3 n=39; Gleason 3+4 n=21). There were significant in-group differences among the one-year cohorts (p<0.02), with increased pathology downgrading over time that includes an 84.2% (32/38) downgrade rate from 2012-2015. Pathology downgrading is significantly associated with lower PSA at biopsy (median 6.9 vs 9.4 ng/ml, p<0.01), decreased tumor percentage (median 12 vs 15%, p<0.03), and lower percentage of positive margins (47.6 vs 66.7%, p<0.04). It is borderline associated with lower percentage of seminal vesicle invasion (11.1 vs 25.6%, p<0.06) and extracapsular extension (49.2 vs 69.2%, p<0.08). Neoadjuvant treatment (14/103), race, age, and clinical staging were not significantly associated with pathology downgrading.

Conclusions

The large, increasing percentage of pathology downgrading implies a high rate of over-diagnosis of Gleason 8 scores on biopsy, potentially leading to suboptimal treatment strategies and much patient distress. Our study adds great urgency to the efforts refining PC diagnostic techniques.

Funding

none