San Francisco—A higher OncotypeDX Genomic Prostate Score (GPS) is associated with an increased risk of adverse pathology in patients who undergo delayed radical prostatectomy (RP) after a period of active surveillance.
In examining a database of men enrolled on AS at the University of California, San Francisco (UCSF), researchers led by Peter R. Carroll, MD, found that each five-unit increase in GPS was associated with a significantly increased risk of adverse pathology and a significantly increased risk of biochemical recurrence following surgery.
The data were presented at the Genitourinary Cancers Symposium in San Francisco by Zachary Kornberg, fourth-year medical student at UCSF, working under Dr. Carroll.
“The GPS was developed for patients with low- to intermediate-risk prostate cancer who would have otherwise qualified for AS but went on to have RP, as a predictor for adverse pathology,” said Kornberg. “We studied a very similar cohort who elected for AS and then went on to have a delayed RP after a short period of AS.”
The GPS is derived from the RNA expression of 17 genes that are associated with a likelihood of having high grade (Gleason pattern 4) and/or high stage (pathologic T-stage 3) if the prostate is removed and examined. The assay can be performed on core needle biopsies.
Of 1,662 men enrolled on AS at UCSF from 1997 to 2016, the investigators evaluated 215 with Gleason score 3+3 or low-volume disease (≤33% positive cores) Gleason score 3+4 prostate cancer on diagnostic or confirmatory biopsy. All 215 men had a PSA level <20 ng/mL, clinical stage T1/2, and Cancer of the Prostate Risk Assessment (CAPRA) score <6, and all underwent GPS testing at diagnostic or confirmatory biopsy (within 24 months).
The primary outcome was adverse pathology at delayed RP, defined as Gleason score ≥4+3, stage ≥pT3a or pN1.