The Prostate Health Index (phi), a noninvasive blood test its developer says is three times more specific in detecting prostate cancer than PSA, is now available nationwide.
The new test’s accuracy decreases the need for many men who test positive for elevated PSA levels to undergo a biopsy in order to achieve a reliable diagnosis, according to Beckman Coulter Diagnostics.
The most widely used screening test for prostate cancer is currently the PSA test; however, it is widely recognized that PSA results can often indicate the possibility of prostate cancer when none is present.
"The PSA test is based on the fact that men with higher levels of the PSA protein are more likely to have prostate cancer," said William Catalona, MD, of Northwestern University Feinberg School of Medicine, Chicago. Dr. Catalona served as principal investigator on the Prostate Health Index clinical study and was the first U.S. physician to run the phi test, which has been used at Northwestern since February.
"However, the problem is that higher levels of PSA can also be caused by a benign enlargement or inflammation of the prostate, leading to many false-positives for cancer and ultimately unnecessarily invasive biopsies and an increased potential for patient harm,” Dr. Catalona said.
The substantial increase in accuracy of the phi test over PSA addresses this concern. Results of a multicenter clinical study found a 31% reduction in unnecessary biopsies due to false-positives as a result of using the phi test (Beckman Coulter U.S. prostate cancer pivotal study report).
"The phi test helps physicians distinguish prostate cancer from benign conditions by utilizing three different PSA markers (PSA, freePSA, and p2PSA) as part of a sophisticated algorithm to more reliably determine the probability of cancer in patients with elevated PSA levels," said Kevin Slawin, MD, of Vanguard Urologic Institute at Memorial Hermann Medical Group, Baylor College of Medicine, and Memorial Hermann Hospital-Texas Medical Center, Houston, who performed some of the key research that led to the development of the phi test and who also began using the test in February. "We have seen first-hand how phi is much more accurate and reduces the need for prostate biopsies. And, the fact that phi is a simple blood test has been very appealing to our patients."
The phi test is now available to physicians nationwide through Innovative Diagnostics Laboratory, a national clinical reference laboratory specializing in personalized blood-based testing to find, understand, and treat cancer.
Dr. Catalona is a consultant/adviser and meeting participant/lecturer for Beckman Coulter.
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