PSA study hinders prostate cancer screening
Just a few millilitres of blood are enough to test men for a special protein produced exclusively by the prostate gland. If the value of the prostate-specific antigen (PSA) is elevated, this may indicate the presence of a tumour in the prostate. However, further investigations are necessary to confirm the suspicion of cancer. Since its introduction in the 1980s, the PSA test has been regarded as the most important instrument for the early detection of prostate cancer, in addition to ultrasound examination of the prostate gland and organ palpation,"says Dr. Stephan Neubauer, urologist at the West German Prostate Center in Cologne. In the course of the urological screening, which is recommended for men over the age of 45, many more prostate carcinomas were discovered at an early and therefore curable stage,"said the urologist from Cologne.
Whether the determination of the PSA value actually leads to a reduction in mortality from prostate cancer, however, has been the subject of controversy for several years now. First and foremost, the doubts about the validity of the PSA test were triggered by the results of a large-scale American study on PSA screening (PLCO study1) in more than 76,000 patients. There was no survival benefit for men who regularly underwent a PSA test compared to the control group, where the PSA value was not determined over the entire seven-year study period. Apparently, as has been shown in a recent review of the investigation2, because the study shows a fatal error: Most of the men in the control group underwent a PSA test on their own initiative.
This is a huge scandal,"said Dr. Neubauer, pointing out the consequences of the scientists' serious mistake: The sobering outcome of the US study led to growing reservations about the effectiveness of the PSA test, which was reflected in recommendations from public institutions. For example, not only in the USA were men advised against taking the PSA test, but reporting in Germany also led to fewer patients taking the test. The renunciation of the PSA test has fatal consequences that will only become apparent in the future,"emphasizes Dr. Neubauer. For example, projections assume that the renunciation of the PSA test for urological screening could cost the lives of some 60,000 American men by 2025.
With over 60,000 new cases per year, prostate carcinoma continues to be the most frequently diagnosed cancer in men and, according to the Robert Koch Institute, is still in third place, especially in terms of mortality with more than 12,000 deaths per year. The new findings once again prove that the PSA test is still the most important instrument for the early detection of prostate cancer,"summarizes Dr. Neubauer. "Otherwise, men with an aggressively growing tumor that would lead to death without appropriate therapy will fall through the precautionary grid."
PSA test can save lives
However, as with any screening examination, the PSA test also carries the risk of "over-therapy". Under certain circumstances, tumours may be treated that would never have led to death. This makes it all the more important to deal with the results correctly,"says the Cologne urologist. Although the interdisciplinary guideline on the early detection, diagnosis and therapy of prostate cancer gives clear recommendations as to when and under what circumstances the test should be used, it still happens that PSA values are incorrectly interpreted and acted prematurely, criticises Dr. Neubauer. For example, a biopsy is often initiated due to briefly increased PSA values, instead of first observing the course of the values.
The prostate specialist also calls for a different approach to tumors discovered by the PSA test:"It must not be allowed for a patient with an elevated PSA level to automatically land on the operating table," said the prostate specialist. Radical prostate surgery, which is still the most common form of treatment in Germany, is often accompanied by a high incontinence and impotence rate. In men with a low risk prostate carcinoma, it can often be sufficient to monitor the tumor closely (Active Surveillance). If treatment should become necessary, however, it is important to focus more strongly on achieving optimal healing rates with minimal side effects, which is usually achieved much better today with modern forms of brachtyhography and radiotherapy than with surgery. In any case, every affected patient should obtain at least one second opinion before he or she decides to remove the organ prematurely,"stresses the urologist.
Shoag JE1, Mittal S1, Hu JC2. reevaluating PSA testing rates