New Prostate Cancer Screening Test Approved in Europe & Awaiting FDA Regulatory Determination in US

Prostate cancer remains the leading cancer diagnosed and the second leading cause of cancer mortality in men in the United States. Despite these sobering statistics, and the common sense notion that earlier detection through prostate cancer screening can reduce these numbers, there remains significant controversy about the role prostate cancer screening should play in the management of this disease.

At the root of this controversy is the use of the Prostate Specific Antigen (PSA) blood test in prostate cancer screening, which has been the mainstay of early detection programs since its development in the early 1990’s. When elevated, the PSA blood test signifies an abnormality in the prostate gland but it is not specific enough to differentiate prostate cancer from other benign problems in the prostate gland, including benign enlargement or inflammation. In order to determine the cause of the PSA elevation, a urologist must perform a prostate biopsy which, while safe, may sometimes lead to complications like infection.

Recently published randomized clinical trials have demonstrated this lack of specificity associated with PSA-based screening leads to some overdiagnosis and overtreatment for each life saved. Based on these findings, the American Cancer Society recently updated their screening recommendations cautioning against routine PSA-based screening without careful input from each patient’s physician, and the American Urologic Association, while reaffirming their support for PSA-based screening beginning at age 40, also emphasized the importance of an individualized approach directed by physicians. Despite these controversies, it is widely agreed that new screening tests that are more specific for identifying aggressive cancers would be a major advance in the field. Over the past two decades, research into the molecular biology of PSA has led to advancements and new tests that have move the field closer to this goal. In 1998, based on a pivotal clinical trial performed by six leading investigators nationwide, including Kevin Slawin, M.D., director of the Vanguard Urologic Institute at Memorial Hermann-Texas Medical Center, the FDA approved the “free PSA” test as a more specific way to differentiate between men with prostate cancer and those with a benign condition when the PSA blood test was modestly elevated. “The PSA test has evolved in the same way measuring cholesterol has,” says Dr. Slawin. “We used to evaluate cholesterol as a single level but now we look at the ratio of LDL (“bad cholesterol”) to HDL (“good cholesterol”) to predict the risk of heart disease. In a similar way, the “free” or “good” PSA in a ratio with the total PSA improved the specificity of PSA testing and reduced the risk of unnecessary biopsies in men with an elevated PSA.

However, over the next decade, through successful use of these tests in ferreting out many men with prostate cancer, the “free” PSA test has lost much of its ability to enhance the specificity of PSA based screening, leaving doctors back to the drawing board in searching for a better, more specific prostate cancer screening test.

Dr. Slawin, instrumental in performing the pivotal studies that led to FDA approval of the free PSA test, has now once again played a leading role in advancing the field of PSA and prostate cancer screening. In studies initiated in his laboratory and published back in 2000, he and his co-workers discovered two novel, disease specific forms of “free” PSA, BPSA or “benign” PSA associated with benign enlargement of the prostate, and [-2]proPSA, associated with prostate cancer. Now, after a decade of clinical development by Beckman Coulter, Inc., which licensed this technology, and after completing pivotal international clinical trials, has obtained regulatory approval for a new test, the “Prostate Health Index (phi)” in Europe and is awaiting a decision by the FDA for determination of this test in the United States. The results of these trials, to be presented at the Annual Urological Association meeting this spring, demonstrated that the “phi” improved the specificity of PSA by 3-fold for the detection of prostate cancer, fulfilling the call for more specific tests to screen and diagnose prostate cancer. Furthermore, researchers at Johns Hopkins recently reported that the phi could also help determine which cancers were the more aggressive needing treatment and which might be safely monitored.

‘It’s been gratifying to play a role in moving the field of prostate cancer screening and early detection forward over the years with focused research on the problem”, Dr. Slawin said. “I’m excited that work we began a decade ago is now finally achieving regulatory approval so that patients and physicians can benefit” he added. Dr. Slawin is continuing his work in advancing the field of prostate cancer diagnosis and treatment, and is a leader in robotic surgery for prostate cancer, and in developing protocols for active surveillance, focal therapy and other modalities of therapy including advance image guided radiation therapy, vaccine therapy, etc.

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