Researchers have found that a new urine test is extremely accurate at detecting aggressive prostate cancer with few false negatives.
The test could have possibly avoided one third of unnecessary prostate cancer biopsies while failing to detect only a small number of cancers, according to a validation study of more than 1,500 patients.
The MyProstateScore test measures levels of cancer-specific genes in a patient’s urine. It’s based on previous research that discovered half of all prostate tumors harbor a certain genetic anomaly in which the genes TMPRSS2 and ERG relocate on a chromosome and fuse together—creating an on-switch for prostate cancer development.
One of the best current methods for detecting prostate cancer is a blood test for prostate-specific antigen, commonly known as the PSA test. Elevated PSA levels may indicate cancer, but the majority of men with an elevated PSA don’t actually have prostate cancer.
To determine which patients do and do not have cancer, men with an elevated PSA test undergo an invasive procedure called a transrectal biopsy. Prostate biopsies are uncomfortable for patients and carry a small risk of complications. MRI scans are also used to detect prostate cancer, but these can also miss cancerous lesions and come with much higher costs and limited availability.
“Our ultimate goal was to determine whether the MyProstateScore test could be a practical, reliable test that could rule out the need for more costly or invasive testing in men referred for a prostate biopsy,” says study lead author Jeffrey Tosoian, a clinical lecturer in urology at Michigan Medicine.
Not all prostate cancers are equally worrisome. Many arise later in life and are so slow growing that the best course of action is to simply monitor them. It is patients with these slow growing cancers or no cancer who, despite elevated PSA levels, could be spared from the more invasive or expensive procedures with a better test, researchers say.
The validation study included patients seen at academic health centers and in community health settings. Among these 1,525 patients, 338—2%— had cancers detected on biopsy tagged group grade 2 or higher, meaning they were serious enough to warrant immediate treatment.
If the MyProstateScore test was available to patients in the study, 387 biopsies that found no cancer or slow-growing cancer could have been avoided, the study finds. Meanwhile, the test would have missed only 10 clinically significant cancers that would have warranted immediate treatment.
“The data show that this straightforward, secondary testing approach could reduce the use of more costly and invasive procedures following a PSA test,” Tosoian says.
Additional coauthors of the study, published in the Journal of Urology, are from Johns Hopkins University, the Fred Hutchinson Cancer Research Institute, and the University of Michigan.
The Prostate Cancer Foundation, the National Institutes of Health, the A. Alfred Taubman Medical Research Institute, and the University of Michigan funded the work.
LynxDX, a University of Michigan startup company that Tosoian and colleagues founded and hold an equity stake in, is commercializing the test.
Source: University of Michigan