ASCO 2017: A 17-gene panel for prediction of adverse surgical pathology in the setting of MRI-guided prostate biopsy

Chicago, IL (UroToday.com) A 17-gene panel (Oncotype Dx Genomic Prostate Score, GPS) has been validated in the past as an independent predictor of adverse pathology (AP, defined as pathological GS 4+3 or higher and/or pT3+) in men treated with radical prostatectomy (RP) for prostate cancer (PCa). Multiparametric Magnetic Resonance Imaging (mpMRI) may help guide prostate biopsies. Dr. Amirali Salmasi presented a study attempting to explore synergies between GPS and mpMRI to aid in PCa management decisions. 

A cohort of PCa men with Low- and Intermediate-Risk NCCN category, who were managed with RP, was identified from a clinical database. Patients were required to have had a simultaneous mpMRI-guided and systematic biopsy, and to have undergone RP within 6 months. Biopsy tissue of the highest Gleason pattern was used for calculation of GPS. The primary endpoint was AP. Secondary endpoints included the range of GPS within UCLA prostate MRI risk groups and median GPS when there was discrepancy between MRI and systematic biopsy Gleason Score (GS). 

134 men met criteria for the primary endpoint. Median age was 62 years (range 46-77). NCCN Low- and Intermediate-Risk PCa was present in 16%, and 84% of men, respectively. Biopsy GS 3+3/3+4/4+3 was present in 19%, 67%, and 13%, respectively. In a univariable model, GPS was associated with AP (OR 3.8, 95% CI 2.1 to 7.4, p < 0.001). After adjustment for highest biopsy GS and clinical T-stage, GPS remained significantly associated with AP (OR 3.4, 95% CI 1.8 to 6.8, p = 0.0004). A wide and overlapping distribution of GPS was noted across UCLA MRI prostate risk groups, indicating that GPS provides information that is distinct from what can be determined from mpMRI. When there was a discrepancy between mpMRI and systematic biopsy GS, mpMRI targeted lesions with higher GS had higher median GPS (33, range 13-70) than systematic biopsies with higher GS (median GPS 25, range 15-55). 

To conclude, GPS provides independent and complementary prognostic information to mpMRI-guided biopsies. The combination of mpMRI for biopsy guidance and GPS for molecular analysis, may optimize prediction of AP and improve patient selection for treatment rather than surveillance.

Presented By: Amirali Salmasi, MD, University of California, Los Angeles, Los Angeles, CA

Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
Twitter: @GoldbergHanan

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 - Chicago, Illinois, USA
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