A non-surgical treatment for low-risk prostate cancer, in which doctors inject a light-sensitive drug derived from deep-sea bacteria into a patient's bloodstream, was found to kill cancer cells without destroying healthy tissue.
Results of a trial on 413 patients showed that half of them went into remission, compared with 13.5 per cent in a control group. The drug is activated with a laser to destroy tumour tissue in the prostate.
"This is excellent news for men with early localised prostate cancer," said Dr Mark Emberton, a Uni- versity College London consultant urologist who led the trial.
The treatment, called vascular- targeted photodynamic therapy (VTP), was developed by scientists at the Weizmann Institute of Science in Israel, in collaboration with the privately-owned Steba Biotech.
WST11, the light-sensitive drug used, is derived from bacteria found at the bottom of the ocean.
To survive with very little sunlight, they have evolved to convert light into energy with incredible efficiency.
WST11, the light-sensitive drug used, is derived from bacteria found at the bottom of the ocean. To survive with very little sunlight, they have evolved to convert light into energy with incredible efficiency, Dr Emberton's team said in a study published in the journal Lancet Oncology.
The Weizmann scientists exploited this feature to develop WST11, which releases free radicals to kill cells when activated by laser light.
Men with low-risk prostate cancer are currently put under active surveillance, where the disease is monitored and treated only when it becomes more severe.
Radical therapy, which involves surgically removing or irradiating the whole prostate, has significant long-term side effects and is used only to treat high-risk cancers.
While radical therapy causes lifelong erectile problems and incontinence, VTP caused only short- term urinary and erectile problems which resolved within three months, the researchers said.
In the trial, only 6 per cent of patients treated with VTP needed radical therapy, compared with 30 per cent of patients in the control group who were under active surveillance.
The trial involved 47 treatment sites in 10 European countries, most of which were performing VTP for the first time.
Dr Emberton said: "The fact that the treatment was performed so successfully by non-specialist centres in various health systems is really remarkable."
The VTP treatment is now being reviewed by the European Medicines Agency for possible licensing, but it will likely be several years before it can be offered to patients more widely.