Cancer? Burn it out! The Romans used to do it.
And now, with a little high-tech help, doctors at University College Hospital in London are doing it.
They're using a light beam of ultrasound to heat up cancer cells in an area as big as a grain of rice to 80 degrees, which destroys them.
Why? Because by focussing on such a small area, they can cut down on damage to healthy tissues and so reduce side-effects.
And they're a big problem for the 37,000 men treated for prostate cancer every year.
Standard treatment - surgery or radiotherapy - leaves a lot on men with serious and embarrassing side effects:
Up to 25 per cent are incontinent
Up to 75 per cent can't get an erection
Up to 10 per cent have problems like diarrhoea
Only 50 per cent manage to avoid one of those three
But in a new trial, funded by the Medical Research Council, 12 months after treatment, none of the 41 men in the trial had incontinence of urine. And, just 1-in-10 suffered from poor erections. The majority of men (95 per cent) were also cancer-free after a year.
Men have a 9-in-10 chance of avoiding all three side-effects.
They'll need a bigger trial to prove that the ultrasound therapy is better than existing treatments, but it's promising.