Background

Uridine 5'-diphosphate-glucuronosyltransferase 2B (UGT2B) genes code for enzymes that catalyze the clearance of testosterone, dihydrotestosterone (DHT), and DHT metabolites in the prostate basal and luminal tissue. The expression of the UGT2B15, UGT2B17, and UGT2B28 enzymes has not been evaluated in prostate tissue samples from hormone therapy-naïve patients.

Methods

We determined the expression of UGT2B15, UGT2B17, and UGT2B28 enzymes in 190 prostate tissue samples from surgical specimens of a multiethnic cohort of patients undergoing radical prostatectomy at the Durham Veterans Affairs Medical Center. The association between each protein's percent positive and H-score, a weighted score of staining intensity, and the risk of biochemical recurrence (BCR) was tested using separate Cox proportional hazards models. In an exploratory analysis, UGT2B17 total positive and H-score were divided at the median and we tested the association between UGT2B17 group and risk of BCR.

Results

The median follow-up for all patients was 118 months (IQR: 85-144). Of 190, 83 (44%) patients developed BCR. We found no association between UGT2B15 or UGT2B28 and risk of BCR. However, there was a trend for an association between UGT2B17 and BCR (HR = 1.01, 95% CI 1.00-1.02, p = 0.11), though not statistically significant. Upon further investigation, we found that patients with UGT2B17 higher levels of expression had a significant increased risk of BCR on univariable analysis (HR = 1.57, 95% CI 1.02-2.43, p = 0.041), although this association was attenuated in the multivariable model (HR = 1.50, 95% CI 0.94-2.40, p = 0.088).

Conclusions

Our findings suggest that UGT2B17 overexpression may be associated with a significant increased risk of BCR. These results are consistent with previous reports which showed UGT2B17 significantly expressed in advanced prostate cancer including prostate tumor metastases.

Introduction

Prostate cancer is a heterogeneous disease, and risk stratification systems have been proposed to guide treatment decisions. However, significant heterogeneity remains for those with unfavorable-risk disease.

Methods

This study included 3335 patients undergoing radical prostatectomy without adjuvant radiotherapy in the SEARCH database. High-risk patients were dichotomized into standard and very high-risk (VHR) groups based on primary Gleason pattern, percentage of positive biopsy cores (PPBC), number of NCCN high-risk factors, and stage T3b-T4 disease. Similarly, intermediate-risk prostate cancer was separated into favorable and unfavorable groups based on primary Gleason pattern, PPBC, and number of NCCN intermediate-risk factors.

Results

Median follow-up was 78 months. Patients with VHR prostate cancer had significantly worse PSA relapse-free survival (PSA-RFS, P < 0.001), distant metastasis (DM, P = 0.004), and prostate cancer-specific mortality (PCSM, P = 0.015) in comparison to standard high-risk (SHR) patients in multivariable analyses. By contrast, there was no significant difference in PSA-RFS, DM, or PCSM between SHR and unfavorable intermediate-risk (UIR) patients. Therefore, we propose a novel risk stratification system: Group 1 (low-risk), Group 2 (favorable intermediate-risk), Group 3 (UIR and SHR), and Group 4 (VHR). The c-index of this new grouping was 0.683 for PSA-RFS and 0.800 for metastases, compared to NCCN-risk groups which yield 0.666 for PSA-RFS and 0.764 for metastases.

Conclusions

Patients classified as VHR have markedly increased rates of PSA relapse, DM, and PCSM in comparison to SHR patients, whereas UIR and SHR patients have similar prognosis. Novel therapeutic strategies are needed for patients with VHR, likely involving multimodality therapy.

Purpose

We evaluated the relative risk of biochemical recurrence, metastasis and death from prostate cancer contributed by biopsy Gleason pattern 5 among men at high risk with Gleason 8-10 disease in the SEARCH (Shared Equal Access Regional Cancer Hospital) cohort.

Materials and methods

Men with biopsy Gleason sum 8-10 prostate cancer treated with radical prostatectomy were evaluated. The cohort was divided into men with Gleason 4 + 4 vs those with any pattern 5 (ie Gleason 3 + 5, 5 + 3, 4 + 5, 5 + 4 or 5 + 5). Predictors of biochemical recurrence, metastases, and prostate cancer specific and overall survival were analyzed using Kaplan-Meier, log rank test and Cox proportional hazards models.

Results

We identified 634 men at high risk in the SEARCH database, of whom 394 (62%) had Gleason 4 + 4 and 240 (38%) had Gleason pattern 5 on biopsy. Baseline characteristics did not significantly differ between the groups. On multivariable analysis relative to Gleason 4 + 4 men at high risk with Gleason pattern 5 showed no difference in the risk of biochemical recurrence (HR 1.26, 95% CI 0.99-1.61, p = 0.065). However, they were at significantly greater risk for metastasis (HR 2.55, 95% CI 1.50-4.35, p = 0.001), prostate cancer specific mortality (HR 2.67, 95% CI 0.1.26-5.66, p = 0.010) and overall mortality (HR 1.60, 95% CI 1.09-2.34, p = 0.016).

Conclusions

Preoperative subclassification of high risk prostate cancer by biopsy Gleason grade (4 + 4 vs any Gleason pattern 5) identified men at highest risk for progression. Any Gleason 5 on biopsy is associated with a greater risk of metastasis, and prostate cancer specific and overall mortality. Grouping all Gleason 8-10 tumors together as high risk lesions may fail to fully stratify men at highest risk for poor outcomes.