Just keeping an eye on prostate cancer results in the same 10-year survival rate as treating it, a study suggests.
The UK researchers warned too many men were having procedures that damaged their sex life and caused incontinence.
A trial of 1,643 men with small prostate cancers resulted in the same 99% survival rate after a decade for those who had had surgery, radiotherapy or simply monitored the tumour.
Experts said the results were “extremely reassuring” for men.
“It’s a global problem that patients are over-treated,” Prof Freddie Hamdy from the University of Oxford, told the BBC.
“It’s understandable, if a 55-year-old man is told they have cancer, and they have a family, they don’t want to take any risks.”
Price to surveillance
In the trial, men whose prostate cancer had been detected by testing for a chemical – prostate-specific antigen (PSA) – in the blood were either monitored, had surgery to remove the prostate or radiotherapy to kill the tumour.
The study, backed by the research wing of the NHS – the National Institute for Health Research – then followed the men for 10 years.
The survival rates were the same, but there was a higher risk of side-effects with treatment.
There was double the risk of incontinence and problems with sex in those having surgery. Radiotherapy increased the risk of bowel problems.
But there was a price to the surveillance option – the prostate cancer progressed in one in five cases.
These men could be treated, but it may affect their long-term survival beyond the 10-year study.
Prof Jenny Donovan, from the University of Bristol, said: “This is the first time radiotherapy, surgery and active monitoring treatments for prostate cancer have been compared directly.
“Each treatment has different impacts and effects, and we need longer follow up to see how those balance out over the next 10 years.”
The findings, in the New England Journal of Medicine, apply only to early stage tumours – those found at a more advanced stage should be treated aggressively.
Dr Matthew Hobbs, from the charity Prostate Cancer UK, said: “At the moment, many men decide against active surveillance because of the uncertainty about the impact of that choice and the anxiety it causes.
“It is extremely reassuring to hear that, when it is performed to a high standard, active surveillance gives men the same chance of survival.”