ORLANDO, FL, USA (UroToday.com) - Undoubtedly active surveillance (AS) is the norm for the majoirty of men diagnosed annually with clinically low-risk prostate cancer.
While the AS avoids side effects from surgery, radiation and other systemic treatments, this course is not without drawbacks. Namely, missing the "window of opportunity to cure." Dr. Cooperberg, emphasized, "We clearly need to improve surveillance strategies for early identification of those cancers which are graded a low-risk but in fact progress quickly. Conversely, we need strategies to identify those tumors that are so indolent, thereby safely reducing the intensity of the surveillance." The emerging role of biomarkers for prostate cancer (deriving from prostate tissue, serum, urine or expressed prostatic fluid.) "Identifying appropriate endpoints for these biomarkers is one of the greatest challenges." He went on to define "progression": the current definition includes PSA kinetics, an increase in tumor grade and/or volume at biopsy. "These are imperfect parameters for a biological meaningful progression: PSA changes (based on current technology) do not consistently predict adverse pathology and serial biopsy may reflect resampling of a static tumor instead of the new growth."There are many questions about the "ideal" study model to evaluate biomarkers. Dr. Cooperberg recommended, "The most critical requirements (for thes biomarker studies) include the ability for all specimens to be collected, processed and archived under consistent conditions, and the assays should be performed and analyzed under strict blinding to outcomes of interest." These emerging biomarkers will need to exceed the existing clinical models in clinical practice with predictive outcomes of approximately 70-80 percent accuracy. The biomarkers in the later stages of development include the PCA3 urinary assay (GenProbe), tissue -based gene expression profiles such as Prolaris (Myriad Genetics), and Decipher (GenomeDx). There are also other markers in early stages of development.
Ultimately, all markers surmounting the hurdles of accuracy, positive and negative predictive value and calibration "will need to establish a cost-effectiveness to decrease over-treatment and over-diganosis of low-risk prostate cancer." Currently, every low-risk prostate cancer case (treatment) is estimate to cost between $25,000 and $50,000.
Presented by Matthew R. Cooperberg, MD, MPH, UCSF, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA at the 2013 Genitourinary Cancers Symposium - February 14 - 16, 2013 - Rosen Shingle Creek - Orlando, Florida USA
View Full ASCO GU 2013 Coverage
Reported for UroToday by Karen Roberts, Medical Editor