Importance of PSA levels in prostate cancer
Prostate carcinoma is the most common carcinoma in men in Germany. Every eighth man is diagnosed with prostate cancer in his lifetime, which makes it comparable in frequency to breast cancer in women. Since it comes only late to symptoms a precaution is very important for early detection.
For this early detection, in addition to the PCa examination – consisting of a medical history, general examination and prostate palpation examination (DRU) – the PSA level can also be determined in principle. Due to its low specificity, however, this is controversially discussed; so far, the value has only been firmly established in the follow-up care of prostate cancer patients. You can find more on this topic here: Examination of the prostate
What is the PSA value?
The PSA value indicates the concentration of the prostate-specific antigen. As the name suggests, this protein is formed in the prostate, an organ directly below the bladder, which is found exclusively in men and forms 10-30% of the sperm. PSA formation is stimulated by male sex hormones – the androgens, which include the well-known testosterone.
In general, a PSA value < 1 ng/ml is considered harmless, since PSA can be detected in every man who has a prostate. This is because PSA belongs to the normal prostate secretion and is therefore physiological in certain amounts. With higher values the value should be checked regularly, with values above 4 ng/ml a more precise diagnosis must be made.
It should be noted that the PSA value always measures only the total PSA, which is also called total PSA (tPSA). However, PSA is not only freely available in the blood, but like many substances it is also bound to other proteins. A further distinction is therefore made between free fPSA and bound or complexed cPSA.
The following applies: tPSA = fPSA + cPSA The free PSA should not be less than 15%, since a low fPSA is suspected of being cancerous. For this reason, the PSA quotient (PSAQ) is often determined today and is calculated as PSAQ = fPSAtPSA and thus indicates the proportion of free PSA in the total value. However, the PSA level alone can only ever indicate cancer and can never be considered as conclusive.
The reason for this is that although PSA is produced exclusively by the prostate gland and is therefore organ-specific, the PSA is not cancer-specific. However, it is not a tumor marker, but generally indicates a change in the prostate, which does not necessarily have to be malignant. Read more about PSA levels
