Another Diagnostic Tool

The ongoing debate about PSA and PCa in men continues and the search for an improved diagnostic tool has also progressed. Three years ago we wrote a piece on Oncosomes. Recently in a JAMA Oncology Editorial the authors speak of this technique as if it has now been accepted. The Editorial concludes:

Currently, we do not have a single population-based screening test to supplant PSA-based  stewardship in screening for prostate cancer. However, McKiernan and colleagues have introduced a novel urinary gene expression signature that may be the least invasive of available options by not  requiring a digital rectal examination or phlebotomy as a reflex test in men for whom PSA testing  raises the suspicion of prostate cancer.7 In the near future, a panel of markers associated with the risk of high-grade prostate cancer may decrease the rate of overdiagnosis and overtreatment of  prostate cancer that prompted the US Preventive Services Task Force to issue a grade D recommendation for prostate cancer screening.

The paper by McKiernan et al presents a several year definitive study of this oncosome approach. They conclude:

This urine exosome gene expression assay is a noninvasive, urinary 3-gene expression assay that discriminates high-grade (≥ GS7) from low-grade (GS6) cancer and benign disease. In this study, the urine exosome gene expression assay was associated with improved identification of patients with higher-grade prostate cancer among men with elevated PSA levels and could reduce the total number of unnecessary biopsies.

 The question is; how effective will this be in saving lives at the cost of saving on unnecessary prostate biopsies. We have commented on this conundrum lately. It is a complex issue. In light of the "Moonshot" approach of the Vice President, this is still somewhat in the pre Galileo period of celestial dynamics.