Prostate cancer is the second most common cancer in American men, second only to skin cancer. Over 233,000 American men are diagnosed with prostate cancer each year, and over 2.5 million are living with the disease even now.
Despite the high prevalence of prostate cancer, until very recently, there wasn’t a reliable blood test available that could tell men whether they have it. Blood tests for prostate-specific antigen (PSA) can tell men if they’re at risk for prostate cancer, but that’s about it.
Elevated blood levels of PSA aren’t always an indication of cancer; they could signal a benign disease, like benign prostatic hyperplasia (BPH), also known as enlarged prostate. They could also signal a non-cancerous tumor. Only a biopsy can diagnose prostate cancer, but that procedure is painful. Now, men can rely on a new test, the Prostate Health Index or PHI, which is 2.5 times more accurate in predicting prostate cancer than older PSA blood tests, to tell them whether or not they really need a biopsy.
How the PHI Works
The PHI is a mathematical formula that measures the true ration of free PSA (fPSA) and [-2] proPSA. One of these molecules is associated with prostate cancer; the other is associated with benign conditions like BPH. Because the PHI distinguishes between the two types of PSA molecule, it can more accurately determine the true cause of high PSA levels. The PHI has been found to be more effective than other PSA measurement tests for predicting the likelihood that cancer will be found upon biopsy. It’s also capable of predicting whether or not cancer will turn out to be aggressive. Treatment options for prostate cancer can vary widely depending on whether the cancer is slow-growing or aggressive. If the cancer is slow-growing, most doctors will recommend a “wait and watch” approach to treatment.
One study conducted by researchers at Harvard Medical School, Johns Hopkins University and other top institutions in the Netherlands and the United States investigated the ability of the PHI to predict clinically significant cancer in men over 50 years of age with a positive biopsy for prostate cancer, benign results on a rectal exam and a PSA measurement of 4 to 10 ng/mL. They found that 18.8 percent of the 658 men studied could have avoided a painful prostate biopsy or over-treatment of a slow-growing form of cancer.
The PHI won FDA approval in 2012. It was the first new blood screening for prostate cancer to win FDA approval in over 10 years.
Standard PSA Tests Often Unreliable
Though the standard PSA screening test has been regularly used to assess the risk of prostate cancer in men over age 50 since 1994, it’s not a very reliable screening procedure. Up to 50 percent of these tests bring back false positive results. That’s because prostate cancer is far from the only condition that can cause elevated blood levels of PSA. BPH, or enlarged prostate, is one such condition. BPH is not believed to be linked to prostate cancer.
The standard PSA screening is so unreliable that the U.S. Preventative Services Task Force has come out against using the test to screen for prostate cancer. They believe that it raises the risk of over-diagnosis — which occurs when a slow-growing cancer or a non-cancerous condition is mistaken for an aggressive cancer — and over-treatment for non-aggressive or non-malignant conditions. Over-diagnosis and overly aggressive treatment can do more harm than good.
Nevertheless, the PHI test isn’t intended to be used as a replacement for the standard PSA screen. The PSA screening exam will still be used, but when it throws up a red flag, patients will be advised to try the PHI instead of proceeding straight to the biopsy. The PHI will be able to determine whether cancer is or isn’t present, and will also be able to tell men and their doctors whether the cancer is an aggressive type that needs prompt, decisive treatment, or a slow-growing type that can be monitored carefully.
For years, men and their doctors relied on an unreliable PSA blood test to screen for the presence of prostate cancer. Now, there’s a new option. The PHI not only more accurately detects prostate cancer, but can even more accurately determine whether or not that cancer is aggressive. The new test will allow men with prostate cancer to make a more informed decision regarding treatment, and enjoy a much higher quality of life.