By Maryanne Demasi at Brownstone dot org.

At a recent Brownstone Institute event, I spoke on a panel about the importance of judging public health interventions by their real-world impact — by whether they genuinely help people live longer and healthier lives.

I had just written about mammography screening, and how decades of research show that while it detects more breast cancers, it doesn't reduce overall deaths.

During the discussion, someone raised the issue about prostate cancer screening and the PSA test.

It was a fair question — because the parallels with routine mammography are striking. Both programs rest on the same seductive logic: find cancer early, treat it, and save lives. It sounds so obvious, doesn't it?

But the latest data on prostate-cancer screening — 23 years of it — suggest that this promise, too, has failed the most important test: overall mortality.

When the Numbers Don't Match the Promise

The European randomised screening study began in 1993 and enrolled more than 160,000 men aged 55 to 69. Half were invited to have regular PSA blood tests; the others were not.

After 23 years of follow-up, published in the New England Journal of Medicine, the results are just in.

Predictably, screening led to about 30% more prostate cancers being diagnosed. However, most were low-risk tumours that never would have caused harm.

Men who were screened had a 13% lower risk of dying from prostate cancer than those who weren't screened.

But that difference, while sounding impressive, shrinks dramatically when translated into absolute numbers: 1.4% versus 1.6%, an absolute reduction of 0.2% (see graph).

That means you'd have to screen about 500 men to prevent one death from prostate cancer — the other 499 see no benefit.

But here's the key point — the overall death rates were identical in both groups (see graph below).

Despite finding more prostate cancers, men who were screened did not live longer — they simply had a higher chance of being labelled "cancer patients."

The study found that while screening can modestly reduce prostate cancer deaths, it comes at the cost of significant overdiagnosis and overtreatment.

The reality for most men is that once a PSA test is positive, it's almost impossible not to act.

At the Brownstone event, I described it like a conveyor belt: once you're on it, it's difficult to get off. An elevated PSA often sets in motion a chain of medical interventions that men may not need.

The Harms We Don't Count

A positive test often triggers a chain reaction — MRIs, biopsies, surgery, radiation — and often with lifelong consequences.

Men who undergo unnecessary treatment can be left impotent, incontinent, or chronically anxious.

Most elevated PSAs are false positives, and even when biopsies reveal no cancer, the process itself carries risk — including infections that can require hospitalisation — and often leads to repeat testing and repeat biopsies.

The psychological toll — months of fear between tests, the dread of results, the pressure to "do something" can be harmful.

A recent study published in JAMA Internal Medicine of nearly a quarter-million US veterans found that even men with limited life expectancy — too old or frail to benefit — were being treated aggressively for prostate cancer.

The authors urged doctors to "avoid definitive treatment of men with limited life expectancy to prevent unnecessary toxic effects."

It's a roundabout way of saying what should be obvious — we're hurting people we can't help.

It's often argued that today's tests and treatments have improved, and while that may be true in some cases, the fundamental problem remains.

The Pressure to Participate

Every October brings Breast Cancer Awareness Month, urging women to get mammograms "for peace of mind."

Every November brings Movember, encouraging men to grow moustaches to raise funds and promote prostate cancer screening in the name of "men's health."

The intentions are good. But these campaigns often create social press...