Tests Might Diagnose, Predict Prostate Cancer

Feb. 26 -- TUESDAY, Feb. 24 (HealthDay News) -- One study suggests that a simple urine test could pick out 50 percent of men with prostate cancer. Another study says that combining risk factors for prostate cancer may help predict the likelihood of developing the disease.

Both studies were presented Tuesday at the 2009 Genitourinary Cancers Symposium in Orlando, Fla., sponsored by the American Society of Clinical Oncology, the American Society for Radiation Oncology, and the Society of Urologic Oncology.

"Current methods for diagnosing prostate cancer -- PSA (prostate-specific antigen) and digital rectal exam -- have low specificity," lead researcher Jack Groskopf, a senior research scientist for Gen-Probe Inc., in San Diego, said during a Tuesday teleconference. "As a result, the majority of prostate biopsies are negative, and you could argue that we are doing too many biopsies."

There is a need for a better test and a better way to determine which men need aggressive treatment and which men need only monitoring, Groskopf said.

Toward these ends, Groskopf's team developed a urine test that can identify particular gene fusions associated with prostate cancer. The gene fusions involve the TMPRSS2 gene and the ERG gene. This particular fusion is found in about 50 percent of men with prostate cancer and can be identified in urine, Groskopf said.

"This is an ideal target for a diagnostic test," he said. "Another exciting aspect of the gene fusions is that they potentially provide an explanation for the progression of prostate cancer."

Using their test in 556 men before they underwent a biopsy, the researchers found the exam had a "specificity" for prostate cancer of 84 percent, compared with 27 percent for a PSA reading. The "sensitivity" of the test was 42 percent, but only half of men with the disease have this gene fusion, Groskopf noted.

The urine test also showed that it correlated well with other measures of gauging the aggressiveness of prostate cancer, Groskopf said.