ORLANDO – Prostate-specific antigen density, total number of biopsies, and later year of diagnosis were significantly associated with disease progression in men under active surveillance for low-risk prostate cancer.
Of 808 study subjects, 554 met strict criteria for active surveillance based on the following criteria: stage less than cT3, prostate-specific antigen (PSA) level less than 10 ng/mL, Gleason score of 6 or less, less than a third of biopsies positive, and less than 50% single-core positive; 254 patients did not meet these strict criteria.
At 5 years after diagnosis, prostate cancer–specific survival was 100%, overall survival was 98%, metastasis-free survival was greater than 99%, and treatment-free survival was 60% Dr. Christopher J. Welty reported at the annual meeting of the American Urological Association.
On multivariate analysis, factors associated with disease progression were PSA density (hazard ratio, 2.06 for 0.1-0.15, and 2.83 for values exceeding 0.15), total number of biopsies (hazard ratio, 0.76), and later year of diagnosis (hazard ratio, 1.16), said Dr. Welty of the University of California, San Francisco. PSA density is based on PSA value per unit volume of prostate.
Study subjects were enrolled in active surveillance at UCSF between 1990 and 2012 and had a mean age of 62 years. Active surveillance consisted of quarterly PSA testing with risk-adapted use of serial prostate biopsy and reimaging. Participants underwent a median of three repeat biopsies during a median of 57 months.
"Of the clinical parameters tested, the likelihood of biopsy progression during active surveillance was most strongly associated with PSA density at diagnosis; the association was modified by prostate size," he said. A stronger association was seen in men with smaller prostates (less than 30 cc), and as expected, patients with larger prostates tended to have lower PSA density than the general cohort, which is a limitation of the study.
This study was supported in part by the U.S. Department of Defense Prostate Cancer Research Program. Dr. Welty reported having no disclosures.