#GU15 - Biomarkers for prostate cancer: Why aren’t we using them and where do we go from here? - Session Highlights

ORLANDO, FL, USA (UroToday.com) - Mark Rubin, MD, from Weill Cornell Medical College, described advances and obstacles in prostate cancer biomarkers and their development. The number of biomarkers has proliferated in this disease, and they perform better than PSA and Prostate Cancer Prevention Trial (PCPT) parameters. However, there is extensive variability in how and when each marker is used. This point was emphasized several times.

gucancerssympaltHe reviewed the EDRN approach to biomarker development, which is a formalized protocol using decision trees to determine when to take each marker to the next developmental stage and emphasizes reproducibility. To this end, the overall goal of each of the clinically localized prostate cancer (CLPCA) markers furthest along in EDRN development is to distinguish aggressive from indolent disease to help make treatment decisions (e.g., surgery, surveillance, etc.). He highlighted the example of addition of TMPRSS2-ERG and PCA3 to PCPT in CLPCA. These additions resulted in an increase in predictive power in identifying Gleason 7 disease, or clinically significant disease at the time of biopsy and upstaging/upgrading at the time of prostatectomy in a large retrospective cohort. However, determining if biomarkers alter treatment decisions is more complicated and hard to measure. Ideally, standardized guidelines would advise clinicians how and when to use biomarkers, but there is no strong institutional or HCO agreement on such indications. This results in a great deal of variability in use. Adding to the confusion, biomarkers are developing at a rapid pace and it is difficult for clinicians to keep up with the technological advances.

He highlighted the precision medicine initiative outlined by President Obama recently and talked about the promise and future of the initiative as it relates to biomarkers. The key tenet of precision medicine is to predict patient outcome, response to drug, or assign therapy in a rational way based on a biomarker or biomarker profile. Currently CLPCA biomarkers have focused on identifying aggressive disease to facilitate treatment decisions, but biomarker development for more advanced disease will need to focus more on treatment response, which will require a different approach. To this end, he stated that further subclassifying tumor types will facilitate treatment algorithms as each subtype may need a different therapy (or no therapy). He mentioned the necessity of developing marker-driven trials to evaluate both treatments and marker accuracy.

He concluded by showing the excess of health care spending in the USA vs return on that spending, compared to other countries. Clearly the United States is an outlier in that most measured outcomes are significantly worse compared to other countries, despite the fact that twice as much money (or more) is spent per capita on health care. He believes that biomarkers can play a role in increasing spending efficiency by guiding more effective treatment decisions.

Presented by Mark Rubin, MD at the 2015 Genitourinary Cancers Symposium - "Integrating Biology Into Patient-Centric Care" - February 26 - 28, 2015 - Rosen Shingle Creek - Orlando, Florida USA

Weill Cornell Medical College, New York, NY USA

Reported by Phillip Abbosh, MD, PhD, medical writer for UroToday.com