NEW ORLEANS, LA USA (UroToday.com) - Dr. Matthew Cooperberg discussed several tissue-based RNA expression assays that are currently being studied. He established that the goals of these markers are to inform physician-patient decisions about optimal initial treatment approach and timing.
These markers, however, must improve on multivariate clinical standard and should be added to established nomograms (such as Stephenson pre-treatment/post-treatment model an d CAPRA score models) and tested if it improves the C-index of these models.
An ideal endpoint of a RNA-based marker in patients with low-risk prostate cancer choosing active surveillance is to accurately predict their long-term risk of metastasis/mortality. Is it safe for them to be monitored or should we intervene? PSA kinetics and Grade/volume progression are both poor markers in active surveillance patients.
Prolaris (Myriad Genetics) is one such marker, based on cell cycle progression (CCP) genes. This test predicts risk of mortality from a prostate biopsy specimen. Ultimately it may help the urologist guide patients on whether they should continue active surveillance or begin interventional treatment. This test is also shown to predict biochemical relapse and metastases following surgery. Oncotype Dx is another marker which is based on 17-gene RT-PCR assay on tissue from needle biopsy. This test indicates the risk of favorable pathology if patients on active surveillance were to undergo prostatectomy. High GPS score in combination with higher CAPRA score increases the risk of unfavorable pathology. One can then counsel a patient to intervene rather than continue active surveillance. In addition to predicting adverse pathology, this test is also validated to predict biochemical relapse after prostatectomy.
While Prolaris and Oncotype Dx are focused on patients on active surveillance, Decipher (Genome Dx) is targeted on post-prostatectomy patients. It is based on 22-gene genomic classifier, which is used to predict metastases among high-risk radical prostatectomy patients. In a recent JCO study, it has been shown to help identify patients who might benefit from adjuvant or salvage radiation therapy post-prostatectomy.
In conclusion, these emerging biomarkers offer improved prognostic information over clinical parameters alone. However, clinical utility and clinical effectiveness need to be conclusively demonstrated before widespread use. Further ongoing studies will help demonstrate their usefulness in clinical practice.
Presented by Matthew R. Cooperberg, MD at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
UCSF Medical Center, San Francisco, CA USA
Reported by Nikhil Waingankar, medical writer for UroToday.com