PSA Density for the diagnosis of prostate cancer

PSA density (PSA density) is a diagnostic parameter obtained by dividing the value of PSA (Prostate Specific Antigen) in the blood for the volume of the prostate, measured by magnetic resonance (MRI) or transrectal ultrasound. This parameter is gaining attention due to its higher accuracy than the PSA free in distinguishing between benign prostatic hyperplasia (BPH) and prostate cancer.

PSA is a protein produced by the prostate, and its levels in the blood may increase in the presence of prostate cancer, BPH or inflammation.

However, the reasons underlying the increase in PSA in the blood are very different from pathology to pathology. In the case of BPH, the number of prostate cells that produce PSA increase. In the case of a tumor, however, the prostate cells transform and gradually lose the ability to produce PSA, but the structure of the organ is gradually compromised, allowing the PSA to escape in large quantities and end up in the blood (source).

This is where PSA density comes into play, which takes prostate volume into account, improving the specificity of the test.

Recent studies have shown that PSA density is a more reliable indicator for the diagnosis of clinically significant prostate cancer than total PSA. Comparing PSA density with other biomarkers, it has been shown that it has a better diagnostic performance and represents one of the most important parameters for the so-called Risk Calculators (source1, source2).

Positions of the Urology Societies

The main urology societies, such as the Italian Society of Urology (SIU) and the European Association of Urology (EAU), recognize the importance of PSA density in their guidelines, particularly for the stratification of subjects with PIRADS 3:

• SIU: The SIU recommends the use of PSA density to improve the early detection of prostate cancer and reduce the number of unnecessary biopsies. In particular, they suggest considering a prostate biopsy if the PSA density exceeds 0.20 ng/mL/cc (source).
• EAU: The EAU includes PSA density in its guidelines for risk stratification in patients with negative multiparametric magnetic resonance imaging (mpMRI) results. They recommend performing a prostate biopsy if the PSA density is greater than 0.15 ng/mL/cc (source).

PSA density represents a significant advancement in the diagnosis of prostate cancer, offering greater specificity than total PSA. Its use is currently showing interest in those patients with a PIRADS 3 on MRI, allowing the discrimination of some doubtful cases.

Scientific evidence and recommendations from the main urology societies support the use of this parameter to improve early diagnosis and reduce unnecessary biopsies, thus contributing to a more effective and less invasive management of patients.

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