New Diagnostic Test Effectively Predicts Rapid Metastatic Prostate Cancer (RMD) – Outperforms Existing Tools

Data presented today at the 2013 Annual Meeting for the American Urological Association by Johns Hopkins University School of Medicine researchers demonstrated that Decipher? (GenomeDx Biosciences), a transformative genomic test that provides a readout of the risk of metastatic disease and disease progression for individual men with prostate cancer, predicted the onset of rapid metastatic disease (RMD) in patients following radical prostatectomy (RP). The test measures the biological risk of metastatic prostate cancer independently of PSA level and other risk factors.

Results of a second study showed that Decipher was a better predictor of metastatic progression than other clinicopathologic variables in men who had experienced a rise in PSA levels, better known as biochemical recurrence, following prostatectomy.

One reason for the higher accuracy of the test is the unpredictability of PSA levels, which can fluctuate as much as 30% for unknown reasons. PSA may increase for reasons independent of cancer which challenges physicians who have to determine how to proceed when PSA levels go up.

Predicting rapid metastatic disease
“Patients who experience metastasis of prostate cancer less than five years after RP are defined as having rapid metastatic disease,” said Doug Dolginow, MD, CEO of GenomeDx. “These patients are most likely to benefit from intensive multi-modal therapy, but predicting which patients have RMD is difficult. A technology such as Decipher may help identify patients and get them appropriate treatment.”

In the study presented by Ashley Ross, MD, PhD, assistant professor of urology at Johns Hopkins University School of Medicine, 4,903 men treated with radical prostatectomy at The Johns Hopkins Hospital who had at least 5 years of complete clinical follow up data were examined. While use of nomograms based on clinical and pathologic features such as CAPRA-S and Stephenson were able to stratify men by risk within the entire surgical cohort, they demonstrated reduced ability to identify patients who would develop RMD in at-risk populations, including men who had adverse pathology at the time of prostatectomy or those who experienced biochemical recurrence. This was primarily due to relatively low sensitivity of these tests.

In collaboration with researchers from the Mayo Clinic, a separate cohort of 1,010 high-risk men, previously analyzed in a validation study for Decipher, were examined. Clinico-pathologic nomograms demonstrated similar deficiencies in this cohort to those seen with patients from The Johns Hopkins Hospital. When compared to clinico-pathologic nomograms, the use of the Decipher test allowed for superior accuracy in identifying men with RMD, with absolute increases in sensitivity of 23% to 39% and an area under the curve (AUC) of 0.79.

Validating test
In a separate study presented by Ross, researchers performed a subset analysis of validation data from the Mayo Clinic and found that Decipher was able to better predict metastasis in a group of high-risk men having already experienced biochemical recurrence (rising PSA) following prostatectomy.

The results of the study showed that the cumulative incidence of metastasis three years after biochemical recurrence was 9% for patients with low Decipher scores but 43% for patients with high Decipher scores (p<0.001). The studies showed that Decipher outperformed PSA doubling time which is currently the best surrogate for metastasis available in the clinic (AUC 0.82 vs. 0.69).

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2013 Annual Meeting of the American Urological Association.

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