April 26 : Studies suggest that a blood test based on early prostate cancer antigen-2, EPCA-2, may greatly improve the ability to accurately detect prostate cancer early, a new study has found.

The study was conducted by a team of researchers led by Robert H. Getzenberg, at The Johns Hopkins University School of Medicine.

Current standards of screening and testing for prostate cancer focus on the blood protein prostate-specific antigen (PSA) along with a digital rectal examination. Men who have more than 2.5 nanograms per milliliter of PSA are considered at risk for prostate cancer. However, PSA testing often erroneously highlights noncancerous conditions (false positives) and can miss some cases of cancer (false negatives).

As part of the study, researchers measured EPCA-2 levels in the blood of 330 Hopkins patients separated into several groups:
-men with normal PSA levels and no evidence of disease
-men with elevated PSA levels but who had negative biopsies,
-men with a common noncancerous prostate condition known as benign prostatic hypertrophy (BPH) who
did not receive biopsies for prostate cancer,
-men with prostate cancer but with normal PSA levels,
-men with prostate cancer confined to the prostate,
-men with prostate cancer that had invaded outside of the gland at the time of surgery, and a diverse group of patients with benign conditions of other organs as well as individuals with other cancer types.

Patients with an EPCA-2 cut-off level of 30 nanograms per milliliters or higher were considered to be at risk for prostate cancer. This cut-off was based on a pilot study of 30 blood samples, which was then applied throughout the larger study.

Researchers found that the EPCA-2 test was negative in 97 percent of the patients who did not have prostate cancer. Men with no evidence of disease (regardless of their PSA levels), as well as the control group of patients with other cancer types and benign conditions, all had EPCA-2 levels below the cut-off.

In addition, 77 percent of the BPH patients had a level of EPCA-2 lower than the cut-off point.

When it came to correctly identifying patients with prostate cancer, EPCA-2 levels at or above the cut-off were detected in 90 percent of the men with organ-confined prostate cancer and in 98 percent of the men with disease outside the prostate. Overall, in this study, the EPCA-2 test detected 94 percent of the men with prostate cancer.

Results of the study also revealed that EPCA-2 levels were significantly higher in patients whose cancers had spread outside the prostate compared to those with disease confided to the gland. EPCA-2 was dramatically better at separating these groups than were PSA levels.

“A blood test based on EPCA-2, may greatly improve our ability to accurately detect prostate cancer early and minimize the number of false positives therefore lowering the number of unnecessary biopsies. In addition, this is the first time we have a test that effectively distinguishes between men with cancer confined to the prostate and those whose disease has spread outside of the gland,” Getzenberg said.

“This is important, since cancer that has spread outside the prostate is more deadly, which makes it even more crucial to have a tool that detects it early,” says Getzenberg.

The findings of the research were published in the April issue of the journal Urology. (ANI)