Urine-based test for prostate cancer promising

February 8, 2008

NEW YORK (Reuters Health) - A combination of biomarkers detectable in urine more accurately detects prostate cancer than the standard PSA blood test and the newer PCA3 test, according to a report in the journal Cancer Research.

Researchers found that a simple urine test that screens for the presence of four different proteins accurately identified 80 percent of men in a study who were later found to have prostate cancer and was 61 percent effective at ruling out the disease in other men in the study.

This is considerably more accurate than the PSA blood test currently used worldwide, which can accurately detect prostate cancer in men with the disease but which also identifies many men with enlarged prostates that do not have prostate cancer, the researchers note. Even the newer PCA3 test, which detects a molecule specific for prostate cancer and which is now in use in the US and Europe is not as accurate as the new urine test, they say.

"Relative to what is out there, this is the best test so far," lead researcher Dr. Arul M. Chinnaiyan of the University of Michigan, Ann Arbor, noted in a written statement.

Using a technique called quantitative polymerase chain reaction, the researchers measured the expression of seven putative prostate cancer biomarkers, including PCA3, in sedimented urine from 234 men having prostate biopsy or radical prostatectomy (removal of the prostate).

Among this cohort, biopsy results confirmed a diagnosis of prostate cancer in 138 patients, while 96 patients were cancer-free.

Results showed that the urine-based biomarker test comprised of four of the biomarkers "outperformed serum PSA or PCA3 alone in detecting prostate cancer," the investigators report.

This test "may be useful as a screening test for prostate cancer, especially in men with elevated PSA," Chinnaiyan told Reuters Health. The next step is to validate these findings on larger independent patient populations from other hospitals."