A urine test for prostate cancer

A new test to detect prostate cancer has arrived on the market. This is Progensa®PCA3 which detects a messenger RNA specific for the cancer gene (PCA3) in the urine. “This test is a complement to current diagnostic tools, such as the blood test for prostate specific antigen (PSA) and digital rectal examination,” said Dr Alexandre de la Taille, urologist at CHU Henri Mondor (Créteil, AP-HP) .
Finding prostate cancer is often a long obstacle course for the patient. As there is no specific marker for prostate cancer, there is always uncertainty about the presence or not of cancer in the face of a low PSA level. Its screening is a public health issue.
With more than 62,000 cases diagnosed in 2005, it is the number one cancer in humans. It is the second leading cause of cancer death with 9,203 deaths per year. This is why when the measured value of PSA is neither frankly high nor strictly normal, the temptation for a urologist is great to resort to a biopsy. “Today, we are doing three series of 12 biopsies,” explains Prof. François Desgrandchamps, head of the urology department at Saint-Louis hospital (AP-HP). Depending on the case, the number of biopsies can be up to 20 per series. ”

The efficiency of the biopsy is neither absolute nor risk-free. “Performing biopsies is never trivial due to the risk of infection or bleeding, not to mention the psychological impact linked to the suspicion of cancer,” notes Dr Alexandre de la Taille. This new test will help reduce uncertainties by providing a more precise result ”. Clinical tests performed on 570 patients have shown that the higher the PCA3 score, the greater the likelihood of prostate cancer.
Thus, for a patient who presents negative results after a first series of biopsies, but with a high PSA, urologists can use this urine test rather than increasing the number of biopsies.

How is the urine PCA3 test done ? The urologist performs a digital rectal examination to squeeze the patient’s prostate and collects a sample of the first urine emitted. This is then sent to a specialized laboratory for analysis. The test costs 300 euros and is not reimbursed by health insurance. “It’s not a revolution, but it’s an additional tool at our service,” says Professor Desgrandchamps. It could compete in certain cases with the use of MRI ”. But urine tests remain the main avenue of research to improve screening for prostate cancer.

Questions to Prof. François Desgrandchamps, head of the urology department at Saint-Louis hospital

An individual approach

Can this urine test replace one of the existing exams?
Prof. François Desgrandchamps. No, the published results are still a little preliminary, but they suggest that PCA3 may be associated with the cancer screening process. This test won’t be a revolution, because it doesn’t tell 100% if you have prostate cancer. This test will only be one more element in a set of arguments. We will tell the patient, you have a negative biopsy, you have a digital rectal examination which is normal, you have a PSA which is not too high, you have a first series of biopsies which is negative, a normal MRI, and you have a PCA3 which is more in favor of something benign, so presumably it’s safe to say that you don’t have cancer. Conversely, if the PCA3 score remains suspect, then efforts must be made to find the cancer.
But the PCA3 test will not locate the area where the biopsy should be done. There may be cancers, those in the anterior area, which cannot be reached by biopsies. In this case, it is only the MRI that can give you an answer. Also, whether the patient has cancer or not does not say whether to treat it.

Do all prostate cancers need to be treated?
Prof FD We only treat serious cancers. First of all, I remind you that serious cancers leave a great life expectancy, between 10-15 years. So, we are in the case of a patient where serious cancer is endangering his life. To know what type of cancer we are dealing with, there is first the dosage of PSA, i And above all, it is necessary to establish the Gleason score, which is the histological characterization under the microscope of prostate cancer, we note on the both the appearance of the cells but also their architecture.
If the Gleason score is between 7 and 10, it should definitely be treated. Below 6, we can ask ourselves the question. Because there are cancers that will evolve over time and those that will not. To know if the cancer will progress or not, we use the PSA doubling time.

Should screening be generalized?
Prof FD Our tools are insufficient to make it compulsory. There is a risk of overtreatment of men with benign cancer. For the moment, this must remain an individual approach by the patient to his attending physician. It is up to the attending physician to educate the patient and to listen to him if he wants a PSA dosage. We must also circulate the idea that being operated on for prostate cancer is not the end of the world. The risk of urinary leakage is now 9%, and the risk of sexual failure is 30% beyond 65 years.
Interview with MG