The approach, tested across Europe, uses lasers and a drug made from deep sea bacteria to eliminate tumors, but without causing severe side effects.
Trials on 413 men - published in The Lancet Oncology - showed nearly half of them had no remaining trace of cancer.
Lifelong impotence and incontinence are often the price of treating prostate cancer with surgery or radiotherapy.
Up to nine-in-10 patients develop erectile problems and up to a fifth struggle to control their bladders.
