Abstract: PD28-03
Sources of Funding: Blue Cross and Blue Shield of Michigan and grant 1T32-CA180984 from the National Cancer Institute

Introduction

There is growing interest among urologists in the community about the extent to which prostate cancer (CaP) genomic tests can further risk stratify men who are candidates for active surveillance (AS). In this context, we evaluated the relationship between results from the Prolaris cell cycle progression genomics test and the frequency of adverse pathological outcomes among men treated with radical prostatectomy (RP) in a large, community-based practice.

Methods

For all patients undergoing Prolaris testing in a large urology practice from 7/2013 through 4/2016, we linked test results with clinical data from the Michigan Urological Surgery Improvement Collaborative (MUSIC) clinical registry. We then identified all men that met the published MUSIC appropriateness criteria for AS (i.e., any Gleason Score (GS) ?6 or GS 3+4 with ?3 positive cores and no more than 50% of any core involved), and also underwent RP as primary therapy. Genomic test results with an estimated 10-year CaP-specific mortality >3% were classified as high-risk. We then compared the frequency of adverse pathological outcomes with RP – defined as the presence of primary Gleason pattern 4 or 5 cancer and/or pathological stage T3 or T4 disease – among men with high- versus low-risk genomics results.

Results

We identified 118 patients who were candidates for AS based on MUSIC criteria, had a Prolaris test, and primary treatment with RP. Among the entire group, 49 (42%) and 69 patients (58%) had low and high-risk genomics results, respectively. When limited to patients with only GS 6 cancer on diagnostic biopsy (n=26), only 4 men (15%) had high-risk Prolaris results. For the entire cohort (Figure 1a), patients with high-risk genomic results were more likely to have pathological stage T3 or T4 tumors (36.2% vs 12.2%, p =0.004). Among the men with only GS 6 cancer on biopsy, none of the 22 patients with a low-risk genomics result had primary pattern 4 or 5 cancer (Figure 1b).

Conclusions

Among patients seen in a large, community practice who are candidates for AS, high-risk results from a cell cycle progression genomics test are more frequently associated with the presence of T3 or T4 disease at RP. Our findings suggest a potentially useful role for these tests in further risk-stratifying men considering AS for early-stage CaP.

Funding

Blue Cross and Blue Shield of Michigan and grant 1T32-CA180984 from the National Cancer Institute