Today the diagnosis of prostate cancer typically begins with an abnormal prostate-specific antigen (PSA) test or perhaps a worrisome finding on a digital rectal exam (DRE). But because an elevated PSA level can be caused by benign prostatic hyperplasia (BPH), prostatitis, as well as prostate cancer, there is a need for a more specific screening test. Now a report in the journal Cancer Research (Volume 68, page 646) suggests that a urine-based prostate cancer test may be the answer.
An experimental prostate cancer screening test that is performed on a urine sample may be more reliable than the traditional PSA test. In a recent study, researchers evaluated a group of biomarkers found in urine for their ability to detect prostate cancer. (A biomarker is a substance found in the blood or other body fluids or tissues that can be used to detect or monitor a disease or to determine the effects of treatment.)
The researchers examined seven biomarkers in urine samples from men scheduled for a prostate biopsy or radical prostatectomy. Then they correlated the results of the procedures with the presence of the various biomarkers.
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Used together, four of the substances -- GOLPH2, SPINK1, PCA3, and TMPRSS2:ERG -- identified which men had cancer. The group of four biomarkers outperformed PSA testing in its ability to specifically identify prostate cancer.
The main problem with PSA testing is that an elevated PSA level may also be caused by benign prostatic hyperplasia or prostatitis. This lack of specificity in PSA testing often leads to unnecessary biopsies. Although early findings are promising, more research is needed to improve the performance of urine tests for prostate cancer. For now, doctors will continue to rely on the current PSA test.
