Nearly all the men had intermediate or high-risk prostate cancer – but 10 years after treatment only two had died from the disease.

These outcomes are as good as surgery or radiotherapy, but with less than half the risk of side effects such as urine leakage or loss of sexual function.

Joint senior author Prof Hashim Ahmed, consultant urologist at Imperial College London and Imperial College Healthcare NHS Trust, said the findings demonstrated that “focal therapy delivers excellent long-term cancer control across a broad range of patients”.

“It makes a compelling case for more centres to offer this treatment,” he added.

Focal therapy was introduced more than 20 years ago but at present only about 1,000 men a year in the UK receive it – despite there being up to 15,000 who could benefit.

The therapy is not suitable for men whose cancer is in multiple parts of their prostate or has spread beyond the gland.