Prostate has long been the Cinderella of cancers, lagging behind others – in particular breast cancer – when it comes to diagnosis, treatment and the funding that goes into research.
But scientists at University College London have made what they believe is a real breakthrough using a drug derived from bacteria found at the bottom of the sea, injected into the bloodstream and activated in the prostate by laser beams. There is also massive excitement from patients, who have been calling UCL ever since the news got out.
The really good news is that this treatment has been shown to kill cancerous cells in the prostate without the serious and sometimes life-changing consequences of surgery. A radical operation to remove the whole prostate gland risks leaving patients incontinent or impotent. That’s why for so many years the standard of care has been to operate only on men who are at high risk of the disease progressing and becoming a killer. The rest are assigned to active surveillance. That means regular testing to ensure the cancer is not spreading – but no treatment. Even symptom-free, many men find that psychologically hard to live with.
Among those under surveillance are men at very low risk, who are very likely to die with their cancer and not of it. But for others at higher risk of the cancer spreading, the new therapy could be really helpful.
The study by Mark Emberton and colleagues, published in the Lancet Oncology journal, tells us a lot about the promise of this therapy, but does not answer all the questions about its future. It could not, Emberton told the Guardian, because the authors had to find a design for the trial that would satisfy the European medicines regulator but without the advantage of technologies that have advanced massively in just the last few years.
“The prostate cancer landscape has been changing so quickly that no trial could keep up with the pace of change,” he said. When they started, just five years ago, MRI scans were not universally available and they had to guess where in the prostate the cancer was. Biopsies are hit or miss.
The researchers focused on 400 men at low risk and treated half with the therapy, placing optical fibres into the prostate to carry the laser beam. The drug is made from bacteria that live on the ocean floor and are adept at converting any light into high intensity energy, which then kills cancer cells when activated in the prostate without harming normal tissue. The other group were given active surveillance as normal.
At the end of two years, the cancer had progressed in 28% of treated patients compared with 58% of those on active surveillance. It was not a clean sweep, but, says Emberton, if they were to do the study now, with the help of MRI scans, they could hit the cancerous parts of the prostate rather than going in blind and the results would be much better. There were side-effects, but mostly they had cleared up by the end of the two years.
What nobody can know is whether the cancer will stay away – the treated patients will be monitored for years to find out.
Emberton and the charity Prostate Cancer UK think the therapy will be most useful in patients in the grey zone – between low and high risk – although for the purposes of the study they had to do it with those at low risk. It is not for everyone. Those at very low risk are still better off with no treatment and no side-effects.
The idea of a drug made of harmless bacteria that can be activated by light to become cancer killers is not a new one. Photodynamic therapy is already being used to treat skin cancer and others where light can easily penetrate. Unfortunately, it has also been abused. Quack clinics offer unproven PDT for brain and other cancers that lasers cannot reach, taking huge amounts of money from families trying everything to save the life of a child.
But this new technology, says Emberton, has been very carefully developed and he believes it could have application in other forms of cancer. He hopes it will get a licence and be approved for use in the NHS – as early as possible, because for now, all they can tell their many callers is that the trial is over and the treatment is no longer available.
