'Field effect' markers may detect occult prostate Ca

Three "field effect" epigenetic biomarkers were found to be more prevalent in histologically benign biopsy cores from prostate cancer patients diagnosed with Gleason score 7 prostate cancer than in those with low-volume Gleason 6 disease, researchers reported at the Genitourinary Cancers Symposium in Orlando, FL.

The study, researchers say, confirms previous findings in a larger cohort of subjects that such markers can be useful for detecting cancer adjacent to histologically negative biopsies and may be indicative of occult aggressive prostate cancer.

In the earlier study, published in the Journal of Urology (2013; 189:1110-6), an assay determining the status of the three biomarkers-GSTP1, APC, and RASSF1-was strongly associated with repeat biopsy outcome up to 30 months after initial negative biopsy in men with suspicion of prostate cancer. The assay, known commercially as ConfirmMDx (MDxHealth, Irvine, CA), was a significant independent predictor of patient outcome (OR: 3.17, 95% CI: 1.81–5.53) in a multivariate model correcting for patient age, PSA, digital rectal examination, and first biopsy histopathologic characteristics.

In the study presented in Orlando, the three markers were tested in a larger cohort to compare histologically benign biopsy cores from patients diagnosed with no cancer, low-volume Gleason 6 cancer, and Gleason 7 disease. Each of 12 tissue cores was tested from a series of 76 biopsy patients: 34 diagnosed with Gleason 6, 22 with Gleason 7, and 20 controls with no cancer.

In 19 of the 22 Gleason 7 cases (86%), epigenetic markers were positive for field effects in one or more adjacent benign cores; 12 (54%) were positive for all three markers. In contrast, nine of 34 Gleason 6 cases (26%) were positive for all three markers.

"We again observed that robust marker expression in histologically benign cores from cases diagnosed with low-volume Gleason score 6 prostate cancer was associated with higher grade cancer at radical prostatectomy (upgrading)," wrote the researchers, led by Sandra M, Gaston, PhD, of New England Baptist Hospital and Harvard Medical School, Boston.

In a related study, a budget impact analysis demonstrated achievable cost savings using the MDConfirmMDx test. The study’s goal was to quantify the impact on costs by avoiding unnecessary repeat prostate biopsy procedures for a managed care plan of one million members that reimburses for the test.

The analysis found that a commercial health plan would realize cost savings within the first year of establishing coverage for the ConfirmMDx test, according to lead author Wade Aubry, MD, of Quorum Consulting, San Francisco. Researchers said the upfront cost will be recovered based on the savings associated with avoided biopsy procedures and associated complications. Inclusion of the test into the management of men screened for prostate cancer resulted in a net cost savings of $588 per patient, researchers reported in the Journal of American Health & Drug Benefits (2013; 6:15-24).

Two of Dr. Gaston’s study co-authors are employees of MDxHealth, and Dr. Aubry is a consultant to the company.