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). If either the PSA test or DRE suggests cancer, transrectal ultrasound or a prostate biopsy will be performed.
But researchers continue to look for a more accurate way to screen for prostate cancer by testing potential biomarkers to supplement the use of PSA. For example, a biomarker called early prostate cancer antigen-2 (EPCA-2), identified by Johns Hopkins researchers, shows promise but confirmatory studies are needed.
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Now, an experimental test that measures levels of a protein in the urine called ANXA3 could help make screening for prostate cancer more accurate. ANXA3 plays a role in cell differentiation and migration.
The study, which comes from Germany and Austria and was published in The Journal of Urology (volume 181, page 343), included 591 men who were being screened for prostate cancer using digital rectal examination and PSA testing. A total of 368 had prostate cancer, and 223 did not.
The researchers found that among the 244 men with PSA levels between 2 and 6 ng/mL, ANXA3 testing missed prostate cancer half the time but had just a 13% rate of false positives. Among the 280 men with PSA levels between 4 and 10 ng/mL, ANXA3 testing missed prostate cancer half the time but had just a 10% rate of false positives. The rate of false positives was even lower when ANXA3 and PSA values were combined.
Up to 75% of all prostate biopsies are unnecessary. The authors of this study predict that the use of ANXA3 could potentially reduce this number to 17%. If further studies support the use of ANXA3 tests, thousands of men could forgo painful, costly biopsies they don't need.
