Men with prostate cancer are being given false hope by tests that underestimate the aggressiveness of their disease, a study suggests.
Researchers found that more than half of a group of men whose cancers were initially classified as slow-growing and confined turned out to have more dangerous tumours.
The findings, published in the British Journal Of Cancer, call into question the ability of experts to grade and stage prostate cancers on the basis of biopsy samples.
It also casts doubt on the "active surveillance" strategy of avoiding unnecessary radical treatment for patients with slow-growing prostate cancer.
Instead, these patients are often closely monitored but left alone until tests suggest their condition has worsened.
More top news
If you have been affected by an issue in our Changing Minds series, are in distress or need some support, help is available 24 hours a day.
The former Deputy Speaker of the House of Lords has resigned following allegations he took drugs with prostitutes. But who is he?
A murder investigation has been launched after a man was fatally stabbed and another injured in an apparent attack at a house in York.