PSA is a protein produced solely in men by the prostate. PSA levels in the blood therefore represent an increase in prostate volume that may be physiological or associated with inflammation or cancer.
In 75% of cases, a PSA level between 4 and 10 ng/mL is associated with benign prostate hyperplasia. The same level indicates a 25% risk of prostate cancer, but the severity or speed of progression remains to be determined (most prostate cancers progress very slowly).
Depending on the clinical examination, including rectal touch, levels of PSA greater than 4 ng/mL are often followed by a prostate biopsy. PSA levels and testing frequency justifying more thorough monitoring are sometimes adjusted based on the person’s age (lower levels in young men and higher levels in older men) or on how rapidly the PSA level increases over time. Several conditions are likely to cause temporary increases in PSA levels in some individuals (prostate massage or recent ejaculation, cycling, acute prostatitis, etc.).