A new form of therapy involving lasers could transform the way prostate cancer is treated
The treatment uses a light-sensitive drug that is then activated by a laser to kill cancer cells
A clinical trial has shown that a new, non-surgical method of treatment for low-risk prostate cancer can effectively kill cancer cells whilst at the same time preserving healthy tissue.
The new treatment is called vascular-targeted photodynamic therapy, or VTP. According to University College London Hospitals (UCLH), the treatment uses a light-sensitive drug, which is injected into the bloodstream. A laser then activates the drug, which eradicates tumour tissue in the prostate.
The drug used is called WST11 and comes from bacteria found at the bottom of the ocean. These bacteria have evolved to turn light into energy in a very efficient way. This trait has been exploited to develop WST11, which UCLH describes as “a compound that releases free radicals to kill surrounding cells when activated by laser light.”
According to UCLH the research, which was published in The Lancet Oncology, showed that 49 per cent of patients given VTP went into “complete remission” compared with 13.5 per cent of patients in the control group.
“This is truly a huge leap forward for prostate cancer treatment, which has previously lagged decades behind other solid cancers such as breast cancer,” Mark Emberton, dean of UCL Medical Sciences and consultant urologist at UCLH, said in a news release on Tuesday. Emberton led the trial.
Prostate cancer is the most common cancer in men across the U.K., according to Prostate Cancer U.K., with 130 diagnosed with it every day and over 10,800 dying annually.
Currently, men diagnosed with “low-risk” prostate cancer have their disease monitored – known as “active surveillance” – with treatment only offered when the cancer becomes more serious. In the trial, just six per cent of patients who were given VTP required “radical therapy” compared to 30 per cent of patients who were placed under “active surveillance”.
Radical therapy involves removing or irradiating the whole prostate, UCLH said, and can have significant side effects including lifelong erectile problems and incontinence. As such, it is only used to treat “high-risk” cancers.
VTP side effects were seen to be short term urinary and erectile problems which resolved “within three months” UCLH said. After two years, no significant side effects were present.
“In 1975 almost everyone with breast cancer was given a radical mastectomy, but since then treatments have steadily improved and we now rarely need to remove the whole breast,” Emberton added. “In prostate cancer we are still commonly removing or irradiating the whole prostate, so the success of this new tissue-preserving treatment is welcome news indeed.”
UCLH added that for patients given VTP the likelihood of their cancer progressing to a “more dangerous stage” was three times lower.
The trial took place on 47 sites across ten European countries, UCLH said, with many sites conducting VTP for the first time. It was funded by STEBA Biotech, holders of the commercial license for the treatment.
“The fact that the treatment was performed so successfully by non-specialist centres in various health systems is really remarkable,” Emberton said.
“New procedures are generally associated with a learning curve, but the lack of complications in the trial suggests that the treatment protocol is safe, efficient and relatively easy to scale up,” he added.
Technological advancements could help to bolster the efficacy of the treatment, Emberton went on to explain.
“We can now pinpoint prostate cancers using MRI scans and targeted biopsies, allowing a much more targeted approach to diagnosis and treatment,” he said.
“This means we could accurately identify men who would benefit from VTP and deliver treatment more precisely to the tumour. With such an approach we should be able to achieve a significantly higher remission rate than in the trial and send nearly all low-risk localised prostate cancers into remission.”
UCLH said that VTP was now under review by the European Medicines Agency.