MP35-15: A 17-Gene Assay Drives High Active Surveillance ... a 1,200 Patient Prospective Observational Trial

A 17-Gene Assay Drives High Active Surveillance Persistence in Clinically Low-Risk Prostate Cancer: 1 Year Results from a 1,200 Patient Prospective Observational Trial

View Poster

INTRODUCTION

Active surveillance (AS) for newly diagnosed localized prostate cancer (PCa) is underutilized; genomic testing information can help inform decisions between AS or Interventional Treatment (IT) in men with clinically low-risk PCa. This study reports on the impact of genomic testing on AS selection and persistence in a prospective observational study conducted in community urologic practices.

METHODS

Men with NCCN® very-low-, low- and low-intermediate-risk PCa were enrolled in a multicenter study of a validated 17-gene tissue-based RT-PCR assay (Oncotype DX® Genomic Prostate ScoreTM; GPSTM). The primary endpoint was AS persistence at one and two years post-PCa diagnosis. The secondary endpoint was the impact of GPS testing on initial decision making. We report the one-year results; the two-year data are forthcoming. This is the first prospective report of the impact of a genomic test on AS persistence rates.

RESULTS

1,200 men enrolled in the study; 796 patients from 25 centers with complete data were included in the analysis. 502 (63%; 95% CI 60%-66%) pursued AS and 294 (37%) pursued IT as initial management. Of the IT patients: 148 (50%) elected surgery, 140 (48%) radiation/brachytherapy, and six (2%) other treatments. After obtaining the GPS result, AS was selected in 87% of NCCN very-low-, 75% of low- (79% for very-low and low combined), and 27% of low-intermediate-risk PCa patients, which compared favorably to AS rates reported in CaPSURE (40% for CAPRA 0-2 in 2010-2013), the MUSIC registry (49% for low risk in 2012-2013), and before GPS testing was introduced into the same practices (40% AS rate overall [50% in NCCN very-low and low combined and 19% in NCCN intermediate] in 2012-2014). Following GPS testing, changes in initial management recommendations from AS to IT or vice versa occurred in 25% (202/796) of patients. In NCCN low-risk PCa, 58 (53%) of the 110 patients initially recommended IT changed to AS, and 44 (17%) of the 253 patients initially recommended AS changed to IT. At one-year post-diagnosis, 452 AS patients had complete follow-up data; 398 (88%; 95% CI 85%- 91%) were persistent on AS overall, and the adherence rate was similar across all risk groups (88% for each).

CONCLUSION

Incorporation of GPS testing helps guide individualized risk assessment and results in a change of initial disease management for one in four men with the greatest impact in NCCN low-risk PCa. Persistence on AS was uniformly high across all risk groups at one year.

Funding: Genomic Health, Inc.