A recent study at Johns Hopkins University has uncovered a new, accurate test for prostate cancer diagnosis. Measuring levels of an early prostate specific antigen called EPCA-2 has been found to be a more effective way to detect prostate cancer than the current PSA test, which more often than not produces false-positive or false-negative results. The EPCA-2 test is not yet available, but with nearly 95% accuracy during clinical trials, it could replace the PSA test as the new gold standard for the assessment of potential prostate cancer patients.
"Prostate cancer is the most common cancer among men, so accurate testing procedures are crucial," explains Dr. Shashi Pawar, PhD, director of molecular biology and genetics at Acupath
Laboratories in New York. "With a new test such as the EPCA-2 test, future patients will be spared the agony of undergoing multiple examinations and procedures only to find out they do
not have the cancer. Also, many patients that would normally go undiagnosed after the PSA test will be treated early on in the disease, which will mean a much longer life expectancy for
prostate cancer patients."
Under current testing procedures, both a digital rectal examination, or DRE, and measurements of the prostate specific antigen in the bloodstream, called a PSA test, are administered to
determine if a patient has prostate cancer. A DRE involves an examination of the prostate to observe physical abnormalities. A PSA test is a blood test that detects the levels of PSA
present in the blood. High levels of PSA indicate a problem, as a healthy prostate secretes very little PSA into the bloodstream.
Experts agree that there are problems with the current accepted tests. "While the PSA test, combined with a DRE, is currently the most efficient way to diagnose prostate cancer, the
diagnosis is often inaccurate because high levels of PSA also signify an enlarged or inflamed prostate, and these conditions are not necessarily related to prostate cancer," says Dr.
Pawar. Following high PSA counts, many patients are advised to undergo invasive procedures such as biopsies. However, roughly 80% of patients that have biopsies do not have prostate
cancer, which shows the inaccuracies of current testing procedures.
In addition to false positive tests, false negatives results are also common with the PSA test. Slow-growing prostate cancers often produce PSA counts within the normal range, despite the
fact that cancer is present. No further treatment is prescribed to such patients, although they may have undetected disease. "Many men who think they do not have prostate cancer do not
have follow-up tests, when they very well could have the disease," Pawar adds.
Published in the April issue of the journal Urology, the clinical study at Johns Hopkins examined 385 men, including patients with PSA levels less than what would cause further testing
under current testing procedures, men with high levels of PSA but with negative biopsy findings, and those with various levels of prostate cancer. By measuring levels of EPCA-2, the study
found that the test detected 94% of prostate cancer overall, compared to the 85% detected through the PSA test.
The EPCA-2 test also correctly diagnosed what would be false-positive and false-negative findings through the PSA test. The EPCA-2 test was negative for 97% of patients who did not have
prostate cancer because it is able to correctly diagnose patients with high levels of PSA but without prostate cancer. In addition, EPCA-2 levels differentiate between patients whose
cancer has spread to other parts of the body and patients whose cancer is contained within the prostate. With this differentiation, the aggressiveness of the cancer and the best treatment
plan can be properly determined.
Johns Hopkins University expects that the larger clinical trials planned for the EPCA-2 test will confirm its accuracy, and this test could be made available to the public in as little as
18 months. In the meantime, the use of other molecular markers for the detection of prostate cancer is being explored. For example, in addition to the PSA test, Acupath Laboratories
currently tests urine samples for the presence of the PCA-3 gene, which indicates that prostate cancer is present." This is a non-invasive procedure, and it has proven to be another
accurate prostate detection method," Pawar claims.
While new prostate cancer testing methods are being experimented with, Dr. Pawar suggests that men over the age of fifty continue with routine PSA and DRE screenings. "Although somewhat
ineffective," Pawar concedes, "The PSA test is currently the best way to detect prostate cancer. As the disease is so common, older men should be tested regularly in order to best treat
the cancer before it's too late."
About Acupath:
Acupath Laboratories, Inc. is an innovative national specialty medical laboratory located twenty miles east of Manhattan in Plainview NY. Acupath's reputation is built on the foundation
of our nationally recognized board certified pathologists, leaders in their fields; many have sub-specialty certification. Acupath performs only pathology, molecular and cytogenetic
exams; ensuring the highest standards in the industry.