Prostate cancer blood tests ‘can lead to men being over-tested’, experts say

Prostate cancer blood tests can lead to men being over-tested, while those who need help may be missed, a large study has found.

Researchers from the University of Oxford examined the health records of more than 10 million men in England and found that many patients are being given prostate specific antigen (PSA) tests much more frequently than recommended.

Repeat testing is also occurring in patients without symptoms, or whose previous tests suggest low levels of risk, according to the study.

Experts also said that celebrities sharing their cancer journeys and advocating for PSA tests is leading to a rise in requests for testing.

The PSA test, which measures the amount of a protein made by prostate gland cells, has proved controversial, with some saying all men should be tested with it at regular intervals to pick up cancer, while others argue the test is unreliable and has not been shown to cut deaths.

Evidence suggests PSA levels can rise for many reasons, including simple infections, and 75% of people with a raised PSA do not have prostate cancer.

A raised level means men can be referred for unnecessary biopsies or MRI, or treated for tumours that may never cause harm.

The PSA test can also miss aggressive cancer. Evidence suggests around 15% of people with a normal result may actually have prostate cancer.

Current NHS guidance recommends PSA testing be considered for patients with urinary tract symptoms, erectile dysfunction, or blood in their urine.

Men over 50 without symptoms can also request a PSA test after consultation with their GP.

The UK National Screening Committee does not recommend widespread population screening owing to limitations in the accuracy of the test and its potential harms, as well as a lack of evidence it reduces deaths from the prostate cancer.

In the latest study, published in the British Medical Journal (BM), some 1.5 million patients had at least one PSA test between 2000 and 2018, resulting in 3.8 million PSA tests overall.

Some 48.4% (735,750) of these patients had multiple tests, with 72.8% (535,990) of them never having a PSA value above the point at which they would normally be referred for testing.

Researchers also noted that patients in their 70s were far more likely to be tested than younger men, and testing rates were higher for white men.

Testing rates were also highest in the South East and lowest in the North East and were more than twice as high in the least deprived groups, compared with the most deprived.

Overall, testing rates were two to three times higher in people without symptoms than in patients with symptoms.

The researchers said: “Although many patients were never tested, suggesting possible under-testing, others were tested only once, which may be insufficient for those at risk.

“We also identified a cohort of patients with low PSA values who underwent frequent testing beyond guideline recommendations, raising concerns about over-testing.

“The benefit of re-testing and ad hoc screening remains uncertain and requires further research to determine evidence-based re-testing intervals that balance the benefits of early detection with the harms of overdiagnosis.”

The authors added that “unpredictable surges in PSA testing, over-testing, and associated costs” may occur as a result of celebrities publicly sharing their cancer diagnoses.

Celebrities including broadcaster Stephen Fry and Olympic cyclist Sir Chris Hoy have spoken about their prostate cancer and the need for checks.

In a linked BMJ editorial, medics said there was a risk “that unregulated PSA testing will result in large costs and harms and increase the incidence of prostate cancer likely to remain undetected, while doing little to identify prostate cancer most likely to cause symptoms and death.”

Naser Turabi, Cancer Research UK’s director of evidence, said: “Prostate cancer is the second leading cause of cancer death in men in the UK, taking around 12,200 lives a year.

“While we’ve seen breakthroughs in treatment, more research is needed to improve how we diagnose the disease.

“As this study shows, detecting aggressive forms of prostate cancer is complex, and the current PSA test isn’t reliable enough.

“Cancer Research UK continues to fund research into ways we can find prostate cancer earlier and save more lives.

“We welcome efforts to ensure testing is targeted, effective, and based on robust evidence.”

Amy Rylance, assistant director of health improvement at Prostate Cancer UK, said: “This BMJ study provides yet more evidence that major inequalities in PSA testing and confusing guidance make it difficult for men and their GPs to know how to test for prostate cancer.

“Despite this, many men are still having tests – but they’re having them unequally. Some are tested more often than necessary, while others aren’t tested until it’s too late.

“The key finding of this study is that men in the affluent South are being tested more often.

“But this needs to be looked at in the context of other research that shows men in affluent areas are also more likely to be diagnosed early, before their cancer has spread.

“That’s why we’ve been calling for the Government to urgently update current guidelines, which are dangerously outdated and continue to cause confusion for men and their clinicians.”