Prostate cancer laser treatment: what you need to know

When a ‘space-age cure’ for cancer that’s ‘truly transformative’ and a ‘huge leap forward’ hits the headlines, it’s going to catch people’s eyes.

And that was the case for one study – published yesterday in the journal Lancet Oncology – that received widespread media attention. The results came from a clinical trial testing an experimental laser treatment on men with prostate cancer. And the findings were positive: the therapy is safe to use in these patients.

That’s good news.

But what do the results really mean for men with prostate cancer? We spoke to an expert on prostate cancer, Professor Malcolm Mason, to find out.

“The great thing is that this study showed the treatment is safe to give to patients,” he says.

“So this is a good study that we can now expand on with further research. But for new treatments, the most important thing is to show that they can save lives. This trial didn’t show that.”

Here’s what it did show.

Lasers for cancer?

While using lasers to treat cancer may sound like a scene from a futuristic film, the technique used in this trial has actually been studied for a number of years for a range of different cancers.

It’s called photodynamic therapy, and it works by combining light-sensitive drugs with lasers. Shining the laser light onto areas of tissue containing the drug causes a chemical reaction that kills the cells nearby cells.

The potential benefits are fewer side effects

– Professor Malcolm Mason

And if it’s a tumour that takes up the drug, directing the light beams towards it triggers a precise attack on the cancer cells. So not only does this have the potential to hit the tumour precisely, it also spares healthy tissue from collateral damage.

For the latest study, the researchers – based at University College London – used a “novel twist” on photodynamic therapy, according to Mason, which “takes advantage of the way that tumours use a blood supply”. This jazzed-up approach is called vascular-targeted photodynamic therapy (VTP).

“Instead of treatments like surgery or radiotherapy which target the whole prostate gland, this technique allows doctors to treat only part of the prostate gland,” Mason explains.

“So the potential benefits are fewer side effects.”

So what did they find?

The trial involved more than 400 men with low-risk prostate cancer, meaning the tumour is unlikely to grow or spread from the prostate for many years. Half of them were randomly chosen to be given VTP, while the others underwent regular monitoring, or ‘active surveillance’.

“Active surveillance allows tumours to progress, and when they start to show signs of progression, you intervene with treatment,” Mason says. This strategy helps to reduce overtreatment, where people are given treatments when their disease would have never progressed, which can cause harm from side effects.

At the end of the trial, tumours in those given VTP took twice as long to progress compared to those being monitored. And almost half (49%) of those treated with the laser therapy had no signs of disease a year after the treatment, compared to 14% of those who were monitored.

It’s too early to tell if the treatment can help improve survival – that’s what we really want to know

– Professor Malcolm Mason

Consequently, fewer men (6%) given the laser treatment chose to have surgery to remove their entire prostate compared to those in the monitoring group (30%).

On top of those results, the researchers found that the laser therapy was safe, causing mostly mild side effects such as urinary and erectile problems that disappeared within a few months.

Although more men in the VTP group had significant side effects compared to those under surveillance, after 2 years these had all resolved.

“The study set out to see if the treatment is safe, and that was the main conclusion,” says Mason.

“But if we look at quality of life, the trial didn’t find a difference between the two groups. And it’s too early to tell if the treatment can help improve survival – that’s what we really want to know.”

Mason also points out that the men involved in the study had a type of cancer that’s known to be linked to a very low risk of death.

“The death rate for this group of patients is around 1% over 10 years, so you’d need many thousands of men to prove that it can boost survival,” he adds.

What now?

Just because this trial didn’t prove that the laser treatment can extend the lives of men with prostate cancer, it doesn’t mean that the research isn’t important. Far from it.

This work has laid the foundations for further trials, and if some of these look at men with higher-risk prostate cancer that’s likely to grow and spread relatively quickly, then it may well be that the treatment can help save lives.

And that would be a huge leap forward.

But for now, it’s important not to over-interpret these results as they stand, and instead see this as a promising area of research that’s still in its infancy.

“It’s really interesting technology,” Mason says. “It definitely deserves to be studied properly, and now researchers have started to do so.”

Justine