Prostate-specific antigen (PSA) is an enzyme produced by prostate tissue. An elevated PSA level in the blood is an important marker of prostate cancer, which is currently the third most common cancer affecting men.
Measurement of blood PSA levels is part of preventive urological screening for men over the age of 40 and for men with a family history of prostate cancer.
The physiological function of prostate-specific antigen is to liquefy semen and facilitate sperm motility. Under normal conditions, only a small amount of PSA enters the bloodstream from the prostate. Elevated PSA levels may indicate increased permeability of the prostate tissue, usually as a result of an underlying pathological condition. This may be prostate cancer, but it can also be caused by benign prostatic hyperplasia (BPH) or prostatitis.
A serum PSA level of 4 ng/ml is generally considered the threshold between normal and elevated values. However, PSA levels naturally increase with age, so the patient's age is taken into account when interpreting the results.
Another important parameter is the ratio of free PSA to total PSA, which helps distinguish between benign and malignant changes in the prostate.
Up to 20% of patients with prostate cancer have PSA levels below 4 ng/ml, while only about 25% of patients with PSA levels between 4 and 10 ng/ml are diagnosed with prostate cancer.
Despite these limitations, PSA remains the most clinically significant biomarker for the detection of prostate cancer.
Early detection and accurate diagnosis are essential for successful treatment. Regular preventive urological examinations are an important part of a responsible approach to men's health and are covered by public health insurance.
