PSA measures a protein produced by the prostate and can be elevated for benign and malignant reasons. PSA is one component of prostate cancer screening; interpretation relies on age, history, exam, and PSA trends. Screening can detect treatable cancers but also causes false positives and overdiagnosis. Shared decision-making, targeted MRI, and active surveillance for low-risk cancers are now common parts of modern care.
What the PSA test measures
The PSA (prostate-specific antigen) blood test measures a protein made by prostate cells. PSA levels can rise for many reasons besides cancer: benign prostatic hyperplasia (BPH), prostatitis (inflammation), recent ejaculation, urinary procedures, or even cycling. A single elevated PSA does not prove cancer; it signals the need for further evaluation.
How PSA is used in screening and diagnosis
PSA is one tool in a larger assessment. Doctors consider age, family history, race, digital rectal exam (DRE) findings, and prior PSA trends (velocity) when deciding next steps. Tests that refine risk include the percent free PSA, PSA density, and prostate MRI before biopsy. If concern persists, a prostate biopsy - now often targeted using MRI - confirms cancer.
Benefits and harms of screening
Screening can detect prostate cancer early, when localized disease may be curable. However, PSA screening also leads to false positives, unnecessary biopsies, and the detection of low-risk cancers that may never cause symptoms (overdiagnosis). Biopsies carry risks such as bleeding and infection; transperineal biopsy techniques reduce infection risk compared with transrectal approaches and are increasingly used in many centers.
Because of these trade-offs, many professional bodies recommend shared decision-making rather than routine blanket screening. Men at higher risk - those with a first-degree relative with prostate cancer or men of African descent - may be advised to start discussions earlier than average-risk men.1
Typical thresholds and interpretation
Historically, a PSA around 4.0 ng/mL prompted further workup, but interpretation is now individualized. Younger men have lower expected PSA values; age-adjusted ranges, PSA velocity (rate of rise), and complementary tests can improve specificity. No single cutoff definitively rules in or out cancer.
Treatment options and active surveillance
Treatment depends on cancer grade, stage, life expectancy, and patient preference. Options include active surveillance for low-risk, localized cancers; radical prostatectomy; radiation therapy (external beam or brachytherapy); and systemic therapies (hormonal therapy, chemotherapy, and newer targeted or immunotherapy agents) for advanced disease. Active surveillance aims to avoid or delay side effects of treatment for cancers unlikely to progress.
Practical advice
Talk with your clinician about your personal risk and the pros and cons of PSA testing. If you decide to test, try to avoid ejaculation and intense cycling 24-48 hours before the blood draw, and tell your clinician about recent urinary procedures or infections. Regular follow-up and trend interpretation are more informative than a single isolated number.
- Confirm current USPSTF and other major guideline recommendations and specific recommended ages for shared decision-making and screening intervals.
- Verify contemporary adoption rates and guidance favoring transperineal over transrectal prostate biopsy and related infection risk data.
- Confirm guideline details on when to begin earlier screening for high-risk groups (exact ages and criteria).