PSA test
The prostate-specific antigen (PSA) test is a blood test used to screen men for prostate cancer. Over 23 years in the largest trial, screening cut prostate cancer deaths by about 13%, roughly 2 fewer deaths per 1,000 men invited, at the price of many more men being diagnosed and treated for cancers that would never have harmed them.
Decide on PSA screening together with your doctor from around 50 (45 with a family history or African ancestry), rather than ordering it by reflex. If you do screen, the better pathway uses a baseline result to space later tests, MRI before any biopsy, and monitoring rather than treatment for low-grade cancer.
What the test measures
PSA is a protein made by the prostate, measured in a blood test. Screening means testing men without symptoms in the hope of finding dangerous cancers early. The question was never whether PSA finds cancer; it does. It was whether finding it earlier saves lives, and at what cost.
Why two big trials seemed to disagree
For two decades a large European trial, the European Randomized Study of Screening for Prostate Cancer (ERSPC), reported fewer prostate cancer deaths with screening, while the US Prostate, Lung, Colorectal and Ovarian (PLCO) trial found no benefit. The conflict largely dissolved once it was clear that many men in the US trial's "unscreened" control group were getting PSA tests outside the trial anyway.[1] After adjusting for lead time, the average amount of time by which screening brings a diagnosis forward, the two trials are roughly compatible: PSA screening cuts the risk of prostate cancer death by about 7–9% for each year of lead time.
The 23-year result: a real but small benefit
After 23 years and 162,236 men, the European trial shows 13% fewer prostate cancer deaths in the screened group, a result clear of no effect. In absolute terms that is about 2 fewer prostate cancer deaths per 1,000 men invited. To prevent one death, about 456 men must be invited to screen and 12 must be diagnosed and treated, both uncertain enough to matter, with plausible ranges of 306 to 943 and 8 to 26. The trade improves with time: at 16 years it took 628 invitations and 18 diagnoses to prevent one death.[2]
The cost: overdiagnosis and overtreatment
Screened men were diagnosed with prostate cancer 30% more often than men who were not screened, while their risk of dying of it fell by only about 2 per 1,000.[3] A US model of 1985–2000 practice estimated that 23–42% of screen-detected prostate cancers were overdiagnosed, meaning they would never have caused symptoms; that was before MRI-first biopsy and routine monitoring of low-grade cancer.[4] Treating cancers that would not have harmed you carries real harms: incontinence, erectile dysfunction, and the heart and blood-vessel side effects of hormone-blocking (androgen deprivation) therapy.
A smarter pathway
Urology guidelines and several European national programmes are converging on a stratified approach: a baseline PSA, longer gaps between tests when it is low, MRI before any biopsy, and active surveillance (regular monitoring instead of surgery or radiation) for low-grade, Gleason 6 cancer.
A Finnish randomised screening trial, ProScreen, put PSA, a blood-marker panel and MRI ahead of any biopsy. In a preliminary report of its first screening round, it found about 4.6 extra aggressive cancers for every extra low-grade one.[5] The urology guideline makes MRI before a first biopsy a conditional recommendation, and a strong one only before a repeat biopsy.[6]
In March 2026 the UK National Screening Committee recommended the UK's first prostate screening programme, but only for men aged 45–61 with a disease-causing BRCA2 gene variant and a family history, explicitly declining screening for all men.
What to do
- Have the conversation around 50, or 45 with a family history or African ancestry, and decide whether screening suits you.
- If you screen, start with a baseline PSA and space later tests out when it is low.
- Ask about MRI before a first biopsy.
- If you are diagnosed with low-grade cancer, ask about active surveillance before agreeing to surgery or radiation.
- Men on testosterone therapy have PSA checked as part of routine monitoring; see Testosterone therapy.