PSA Test: Do you have any questions?
Frequently Asked Questions (FAQ) about Prostate Specific Antigen (PSA)
What does PSA mean? What role does the PSA test play in the early detection of prostate cancer? What are the benefits and risks? Experts from the West German Prostate Center (WPZ) at the KLINIK am RING in Cologne answer the most important questions on the subject of PSA.
PSA in general
PSA - what is it?
PSA is an abbreviation for "prostate specific antigen". This is a protein that is produced exclusively by prostate cells and serves to liquefy the sperm. Since the prostate is very well supplied with blood, small amounts of PSA constantly enter the blood. In order to determine the PSA value, a blood sample is taken and the PSA concentration is determined in the laboratory. The PSA value is given in nanograms per millilitre of blood (ng/ml).
What does the PSA value say?
The prostate specific antigen is produced by each prostate cell. A PSA value within the normal range therefore usually also indicates normal prostate activity. If the prostate enlarges, the prostate cells produce more PSA, which can result in an "increased" PSA level. The prostate specific antigen is a tissue marker and NOT a tumor marker. The test result therefore always only predicts the probability that a prostate carcinoma is present. There are numerous reasons why the PSA in the blood can be elevated in the short term. Conversely, a normally high PSA level does not automatically mean that there is no prostate cancer.
Why can the PSA level be elevated?
By no means every patient whose blood level exceeds the 4 ng/ml limit suffers from prostate cancer. This is because inflammations of the urinary tract or prostate, benign changes as well as pressure on the prostate, e.g. through a digital rectal examination or through sporting activities such as cycling or riding, but also sexual intercourse and ejaculation can cause the PSA in the blood to rise in the short term. This makes it all the more important not to panic when the PSA levels are raised once, but to repeat the test several times and also use other diagnostic procedures.
What should be considered before taking blood samples for the PSA test?
Since the prostate reacts sensitively to pressure, mechanical irritations can stimulate PSA production and falsify the result of the PSA test. Urologists therefore recommend that you avoid cycling and sexual intercourse two to three days before taking a blood sample for PSA measurement. A palpation examination of the prostate can also increase the PSA level in the short term and should always be carried out after blood collection for PSA determination.
PSA as a preventive measure
When and how often should the PSA test be performed?
According to the current guidelines of the German Society of Urology (DGU), the test is recommended from the age of 45 years (in the case of family disposition from 40 years). How often the test should be repeated depends on the test result: If a PSA value of less than 1ng/ml was measured, a further check is only necessary after 4 years. If the value is above 2 ng/ml, an annual check should take place. If the values are lower, the interval of the PSA determination can be extended after evaluation by the urologist.
At what point is the PSA test conspicuous?
In general, PSA values between 0 ng/ml and 4 ng/ml are considered "normal". However, values between 2ng/ml and 4ng/ml are considered to be in need of control. In order to be able to assess the test result, however, not only the absolute level of the PSA value but above all changes over time as well as the age of the patients play an important role.
|50 - 59 years||under 3.0 ng/ml|
|60 -69 years||under 4.0 ng/ml|
|over 70 years||under 5.0 ng/ml|
Table: PSA standard values depending on age (Source: DGU)
Is the PSA test alone sufficient to make a suspicious diagnosis?
The single measurement of the PSA value, however, has only a limited informative value and is not sufficient alone to make a diagnosis. An increased PSA level may have other reasons. It is therefore important to repeat the test promptly and, if necessary, to use other diagnostic procedures in addition to ultrasound and palpation for further clarification. It is always absolutely necessary to have an expert evaluation of the overall findings of a man and not an isolated evaluation of the PSA test result. If the overall results actually indicate prostate cancer, tissue samples are taken from the prostate and examined for cancer cells in the laboratory (prostate biopsy).
PSA and early detection
What role does the PSA test play in the early detection of prostate cancer?
The PSA test is currently the only screening test that can detect prostate cancer at a very early, easily curable stage. For example, the introduction of the PSA test in the 1980s led to prostate tumors being detected about five years earlier on average. This is the crucial time during which curable disease stages can become incurable diseases. The European Screening Study (ERSPC) has shown that the risk of dying from prostate cancer can be halved by PSA-based screening.
Why is the PSA test controversial?
Opponents of PSA often argue that most men die with prostate cancer rather than from it. In fact, the PSA test can also detect "irrelevant" carcinomas that may not have led to the death of the patient. The fact remains thereby disregarded that according to Robert Koch institute each year still 11,000 to 12,000 deaths are to be deplored by Prostatakrebs - patients, whose diagnosis reads ?incurable?, because it was recognized in many cases too late. If patients are denied the PSA test, men with an aggressively growing tumour, which would lead to death without adequate therapy, are deprived of the possibility of healing.
Are palpation and ultrasound not sufficient for the early detection of prostate cancer?
The early detection of prostate cancer by digital rectal examination (DRU) alone is insufficient and often a "late detection". In the DRU, the urologist scans the prostate from the rectum to detect any hardening that may indicate a tumor. However, only superficial tumours that have reached a certain size can be detected with the palpation examination. The disease may then be at an advanced stage and is only curable to a limited extent. Studies have shown that out of 12 prostate cancer patients, 11 cases are detected by PSA measurement and only 1 by digital rectal examination.
What are the risks of PSA testing?
Although the guidelines for the early detection, diagnosis and treatment of prostate cancer provide clear recommendations as to when and under what circumstances the test should be used, it still happens that PSA values are misinterpreted and "acted upon" prematurely. For example, biopsies are often performed due to temporarily elevated PSA levels rather than initially observing the course of the levels. Or patients with a low risk stage are treated unnecessarily with invasive therapy such as surgical removal of the prostate (prostatectomy). The overtreatment of prostate cancer - i.e. unnecessary treatments with possible side effects - is a major problem in Germany. However, this is not the fault of the PSA test, but of how the results are handled.
PSA in follow-up care
What role does the measurement of the PSA value play after the end of therapy?
Once the treatment is complete, follow-up begins. The PSA test also plays an important role here. Regular checks of the PSA value should ensure that a relapse (relapse) after surgery or radiotherapy is detected in good time. Tumor cells that have colonized the body as metastases outside the prostate also produce PSA. PSA is measured every three months during the first two years, every six months during the third and fourth years, and every 12 months after five years. This applies both to radical prostatectomy and to external radiation and brachytherapy.
How does the PSA value behave in the event of a recurrence of prostate cancer?
If the prostate was surgically removed with the tumour (radical prostatectomy), the PSA level should drop below the detection limit (below 0.2 ng/ml) within four to six weeks. If the PSA level rises, the tumour may grow again. A relapse (relapse) after radical prostatectomy occurs when the PSA level rises above 0.2 ng/ml in two consecutive measurements. In technical terminology such a case is referred to as "biochemical relapse" or "PSA relapse". If, on the other hand, brachytherapy or external irradiation was used, the PSA level decreases slowly over months. The lowest value ("nadir") is individually different.
Does a PSA increase after brachytherapy automatically mean a relapse?
In more than one third of all patients with prostate cancer who were treated with brachytherapy, an increase occurs again after a primary decrease in PSA, which then spontaneously decreases again after some time. Such a temporary increase in PSA usually occurs 1 to 1 ½ years after brachytherapy and decreases again after an average of 18 to 20 months. The reason for such a PSA bounce is usually an inflammation of the remaining prostate tissue (prostatitis) induced by radiation, which, however, does not require treatment. A short-term increase in PSA after brachytherapy therefore in most cases does NOT indicate renewed tumour growth in the prostate (local recurrence).