Researchers have found that a new urine test is extremely accurate in detecting aggressive prostate cancer with few false negatives.
The test could have possibly avoided one-third of the unnecessary prostate cancer biopsies, but according to a validation study of more than 1,500 patients, only a small number of cancers could be detected.
The MyProstateScore test measures levels of cancer-specific genes in a patient’s urine. It is based on previous research that has discovered that half of all prostate tumors contain a certain genetic abnormality in which the genes TMPRSS2 and ERG move on a chromosome and fuse together, creating a switch for the development of prostate cancer.
One of the best methods to detect prostate cancer is a blood test for prostate-specific antigen, commonly known as the PSA test. Elevated PSA levels may indicate cancer, but most men with elevated PSA do not 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 it can also miss cancerous lesions, which have much higher costs and limited availability.
“Our ultimate goal was to determine whether the MyProstateScore test could be a practical, reliable test that eliminates the need for more expensive or invasive testing in men referred for a prostate biopsy,” said Jeffrey Tosoian, a clinical lecturer in the study. urology at Michigan Medicine.
Not all prostate cancers are equally worrying. Many emerge later in life and grow so slowly that the best way is to simply monitor them. It is patients with this slow-growing cancer or no cancer who, despite increased PSA levels, can be spared some of 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 institutions. Among these 1,525 patients, 338-2% developed cancers in biopsy marked group grade 2 or higher, meaning they were severe enough to warrant immediate treatment.
If the MyProstateScore test were available to patients in the study, 387 biopsies that found no cancer or slow-growing cancer could be avoided, the study found. Meanwhile, the test would have missed only 10 clinically significant cancers that would immediately warrant treatment.
“The data show that this straightforward, secondary testing approach can reduce the use of more expensive and invasive procedures after a PSA test,” says Tosoian.
Additional co-authors of the study, published in the Journal of Urology, is 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 training company in which Tosoian and colleagues founded and own a stake, is commercializing the test.
Source: University of Michigan