“Not everything that counts can be counted, and not everything that can be counted counts.” Few statements capture the challenge of prostate cancer screening more precisely than this one.
For years, the debate around prostate cancer screening—particularly the use of PSA (prostate-specific antigen) tests—has been marked by a tug-of-war between two realities: the promise of early detection, and the very real risks of overdiagnosis and overtreatment. While population-level screening has transformed outcomes for many other cancers, prostate cancer has stubbornly resisted a simple narrative.
The PSA Paradox
At the heart of the controversy is the PSA test itself. Though widely used, it is neither perfect nor definitive. High PSA levels may not always indicate cancer, leading to false positives that trigger anxiety and invasive follow-up procedures such as biopsies. At the same time, certain aggressive prostate cancers produce little PSA, slipping under the radar. Others grow so slowly that they may never pose a threat within a patient’s lifetime.
This raises important questions about what screening should achieve and whom it should serve.
What We Must Know Before Promoting Screening
Any discussion about PSA testing must consider three fundamental realities:
- Does screening actually reduce prostate-cancer–specific mortality?
- What is the true accuracy of PSA testing in asymptomatic men, its sensitivity, specificity, and predictive value?
- What are the physical and psychological harms of screening?
Evidence over the decades has been complex and sometimes contradictory. A shift in detected disease stages—often cited as proof of screening success—may instead reflect the Will Rogers effect, in which improved detection merely reshuffles diagnostic categories without reducing deaths.
Prostate cancer is also unique in another way: it has a long mean sojourn time. Many cancers sit silently for years before becoming detectable or clinically significant. This makes early detection both possible and deceptively reassuring.
No Case for General Population Screening, Yet
Today, global evidence still does not support general-population prostate cancer screening. Unlike breast or cervical cancer, where population-wide screening has a strong evidence base, prostate cancer does not meet the threshold for mass screening.
But that does not mean PSA has no place in clinical practice.
Growing research further suggests that a single PSA test in midlife may provide valuable predictive information.
- A midlife PSA (around age 40–50) above 1.4 ng/ml is associated with a higher future risk of prostate cancer.
- A single PSA at age 60 can help distinguish men who require ongoing surveillance from those who do not.
- Conversely, a low PSA in midlife may safely exclude some men from further screening entirely.
This is a more refined, personalised approach, one that moves away from blanket screening toward risk stratification, where PSA serves as a triage tool rather than a blunt instrument.
Where PSA Screening Does Have a Role
Outside the general population, PSA testing is clearly relevant for certain groups:
- Men with a family history of prostate cancer
- Men of African-Caribbean descent, who face higher risks
- Individuals over 40–50 years old with symptoms, including lower urinary tract symptoms (LUTS) or microscopic haematuria
PSA also remains critical in the ongoing management of those already diagnosed, helping with:
- Monitoring disease progression
- Prognostication
- Assessing aggressiveness through PSA kinetics, velocity, density, and free-to-total PSA ratios
An Approach Rooted in Dialogue, Not Default Testing
If there is one principle that should guide the future of prostate cancer screening, it is this:
A single PSA test taken after an informed discussion between clinician and patient can be a valuable tool for identifying who may benefit from surveillance.
This is not screening in the traditional mass-population sense. It is targeted, evidence-informed risk stratification.
The Path Forward
We must resist the urge to oversimplify prostate cancer screening. A test that provides clarity for one man may result in confusion and unnecessary harm for another. PSA testing is neither wholly good nor wholly bad, it is a tool, useful only when applied with nuance.
Not everything that counts can be counted. And in prostate cancer screening, not everything that can be counted should automatically count.
What matters most is thoughtful, personalised decision-making, guided by evidence, shaped by individual risk, and rooted in meaningful doctor–patient conversations.
