A brand new urine check might keep away from pointless prostate most cancers biopsies
A urine test based on research by the University of Michigan's Rogel Cancer Center could have avoided a third of unnecessary prostate cancer biopsies while leaving only a small number of cancers undetected, according to a validation study that included more than 1,500 patients. The results appear in the March issue of the Journal of Urology.
The MyProstateScore test, commercialized by LynxDX, a U-M startup, measures the levels of cancer-specific genes in a patient's urine. It is based on U-M research that found that half of all prostate tumors have a specific genetic abnormality, where the TMPRSS2 and ERG genes shift and fuse on a chromosome – a switch for the development of prostate cancer.
Currently, one of the best ways doctors can use to detect prostate cancer is to do a blood test for prostate-specific antigen, commonly known as a PSA test. Elevated PSA levels can indicate cancer, but the majority of men with elevated PSA actually do not have prostate cancer.
To determine which patients have cancer and which do not, men with an elevated PSA test undergo an invasive procedure called a transrectal biopsy. Prostate biopsies are uncomfortable for patients and pose a low risk of complications. MRI scans are also used to detect prostate cancer. However, these can also miss cancerous lesions and are associated with much higher costs and limited availability.
Our ultimate goal was to determine whether the MyProstateScore test can be a convenient, reliable test that eliminates the need for more expensive or invasive testing in men referred for prostate biopsy. "
Jeffrey Tosoian, M.D., M.P.H., Study Director, Clinical Lecturer in Urology, Michigan Medicine
Tosoian and two of his co-authors were founders of LynxDX and have a stake in the company.
Not all prostate cancers are equally worrisome. Many emerge later in life and grow so slowly that the best course of action is to simply monitor them. It is patients with these slow-growing cancers or without cancer who, despite elevated PSA levels, could be spared the more invasive or expensive procedures if doctors had better tests, the researchers say.
The validation study included patients seen in academic health centers and community health facilities. 338-22% – of these 1,525 patients were found to have Group 2 or higher cancers on biopsy, which means they were severe enough to warrant immediate treatment.
If the MyProstateScore test had been available to patients in the study, 387 non-cancerous or slow-growing cancer biopsies could have been avoided. In the meantime, the test would have missed only 10 clinically significant cancers that warrant immediate treatment.
"The data shows that this simple secondary testing approach could reduce the use of more expensive and invasive procedures after a PSA test," says Tosoian.
Michigan Medicine – University of Michigan
J. J. Tosoian et al. (2021) Using the MyProstateScore Test to Rule Out Clinically Significant Cancer: Validating a Simple Clinical Test Approach. Journal of Urology. doi.org/10.1097/JU.0000000000001430.