Years of basic research on the molecular basis of prostate cancer appear to be about to pay dividends. Several recent laboratory studies have demonstrated results that may impact the care of patients with prostate cancer. These so-called "translational" studies are the important link between basic laboratory research and actually improving the treatment of real-life patients.
The Holy Grail of prostate cancer research.
Prostate cancer has varying levels of aggressiveness. Over 200,000 men are diagnosed with it each year in the U.S., but only 30,000 will die from it. Clearly, some people who are treated for prostate cancer may not have needed treatment. But equally as concerning is the 30,000 men who were either diagnosed too late, or did not receive enough treatment after diagnosis.
One of the problems with our current approach to prostate cancer, is that we don't really know how aggressive the cancer is until it is completely removed by surgery. For patients who undergo other forms of treatment, like radiation, we never truly know how aggressive it was. These new tests aim to improve our knowledge of the cancer before treatment. The ultimate goal would be to know at diagnosis if patients needed treatment for their prostate cancer or not, or if they needed additional treatment after surgery.
How do these new tests work?
Right now, the tests are very early in development, and none have been approved by the FDA yet. Some look for specific genetic changes in the prostate cancer tissue that is removed at the time of prostate biopsy. Certain genetic mutations in the cancerous tissue, the details of which are quite complex, result in a more aggressive form of prostate cancer. If we knew that patients had these mutations, we might recommend additional treatment following surgery. Others are urine-based tests, which detect levels of certain substances secreted by the prostate into the urine after a rectal exam.
One such substance, known as PCA3, appears to be more specific than the traditional PSA blood test. This test, made by Gen-Probe, Inc., is already clinically available, but not yet FDA approved. It may help us determine which patients with an elevated PSA might not need a biopsy. Similarly, a new "super-PSA" blood test panel of PSA and three of its sister molecules in the blood may help to better discriminate which patients should or should not get a biopsy.
Should I ask my urologist about these tests?
Not yet. While the early reports on these tests are promising, more research still needs to be done to see how useful they will be in patients. Also, without FDA approval, Medicare will not pay for these tests and it is very unlikely that private insurance carriers will. Hopefully within the next few years these tests will have made it from the laboratory bench to the bedside with an FDA seal of approval, improving the care we give to patients with prostate cancer.