Expert Opinion – Professor Richard Gilbertson talks children’s cancers

New figures we’ve released today show that childhood cancer deaths have dropped 24 per cent in the last decade.This is great news, reinforcing the excellent progress made in children’s cancers over the last 40 years as survival has tripled. But it also shows that there’s more still to be done.

And Professor Richard Gilbertson is one of many researchers leading the way. He recently joined our ranks as director of our Major Cancer Centre at Cambridge University from St Jude Children’s Research Hospital in the US, and has been working in paediatric oncology as both a clinician and a researcher for almost 25 years. 

We caught up with Richard to ask what he made of the new figures, the challenges facing research into children’s cancers, and where the field is heading.

What made you decide to pursue a career in children’s cancers?

At medical school, as a 19 year old, I was particularly interested in a type of children’s brain tumour called medulloblastoma. And here I am at the age of 48 still working on it – so why did it profoundly affect me?

There were two things that really stick in my mind: the first was as a medical student in the 1980s. I walked into a paediatric ward and there was a dark corner where a family was gathered around a child in a bed. We were told that we weren’t allowed to go in, because the child was dying of a brain tumour.

How can the only option be to let a child die in peace?

After that I decided I wanted to do something about children’s brains tumours

– Professor Gilbertson

I asked what treatments were available for her, and they said: “There aren’t any. We’ve done everything we can. All we can do now is let her die in peace.”

And that just really angered me. How can the only option be to let a child die in peace?

After that I decided I wanted to do something about children’s brains tumours.

The other incident was later that year in the pub with my friend Nigel, another medical student, after a long night on call together. We were talking about our long term ambitions and goals. And Nigel said to me that, as doctors – whether we work in geriatrics, paediatrics or whatever – at the end of our career we should aim to have been responsible for a 15 per cent reduction in deaths from diseases affecting those patients.

The idea of having a measurable goal, rather than just a career in medicine, profoundly affected me. It’s the reason that in the year 2000 I left the UK for St Jude’s Children’s Research Hospital in the US, and dedicated all my time to research understanding childhood brain tumours.

It was a struggle to give up seeing patients because I absolutely loved clinical medicine, but I felt that the lab, rather than the clinic, was the place I could have the greatest impact for all children with brain tumours, wherever they lived. The lab was where I was most likely to achieve that 15 per cent drop in mortality.

What did you discover in the lab as opposed to the clinic?

One of the things we were able to show was that children’s brain tumours shouldn’t be treated as just one disease. In fact, we have shown that the reason they are different is because they arise from totally different cells in the brain.

We used to think of brain tumours as being one type of disease, such as medulloblastoma or ependymoma. More recently we have realised that there are actually four different types of medulloblastoma, but nobody knew why.

Our work showed these subtypes are actually completely different from the start. They begin from different cells in the brain and have different flaws in their DNA. Now that we know which genetic flaws to look for, we can search for new drugs that target them.

What does this mean for treatments?

First, we have discovered completely new drug targets for children with brain tumours and are looking at 1000s of different molecules that may hit these targets. We have also shown that one type of medulloblastoma is much more sensitive to treatment than the others. But at the moment all children are all still given very high doses of radiotherapy, when perhaps they don’t need as much.

We also think we may have found one of the reasons why this type of tumour is so responsive to treatment. We are now looking to see if we can expose this weakness in the other tumour types, and improve the cure rates there as well.

Do you think we are making as much progress as we should be?

We know much more about what lies ‘under the bonnet’ of brain tumours, providing us with a much greater chance of fixing them forever

– Professor Gilbertson

It’s actually an incredibly exciting time for research in childhood brain cancers, since we understand brain tumours better than we ever have at any point in history.

Let’s take an analogy. I know nothing about cars other than the colour! So if something goes wrong with my car I haven’t the first idea how to fix it.

That was like our knowledge of brain tumours 20 years ago – we just knew what they looked like. Now we know much more about what lies ‘under the bonnet’ of brain tumours, providing us with a much greater chance of fixing them forever.

What’s behind the falling death rates in children’s cancers?

The main reason death rates are falling is that we’ve refined our whole approach to treating children with cancer. There have been gradual improvements in surgery, radiotherapy, and how we care for very sick children, including using antibiotics more effectively for children with a compromised immune system.

Essentially, we’ve learned how to use the treatments we already have, as best as we possibly can. And at this point I think we’ve had the most ‘bang for our buck’ on existing treatments.

The next stage in making sure that even fewer children die from cancer will be to develop even better treatments. And we are in a great position to do that, because our understanding of the biology has caught up.

Where do you see children’s cancer treatments in the next 5-10 years?

I think there are four key areas where we will see new treatments.

The first is known as ‘repurposing’, where we take drugs used for adult cancers or other diseases and use them to treat children. Children’s cancers are relatively rare, so you can’t possibly test every single cancer drug in a children’s clinical trial. But with new technologies we are now able to test more promising existing drugs more quickly in the laboratory.

The second is developing treatments that specifically target faults in children’s cancers, so called targeted treatments. We are starting to see these being developed in children’s cancers such as neuroblastoma and brain tumours and these could prove to be far more effective treatments.

Then there’s the whole field of immunotherapy, which is an extremely exciting area. There have clearly been some recent successes in immunotherapy, which uses the body’s immune system to fight cancer. But it’s really an untapped area for treating children and would be an entirely new approach.

The fourth area, which is extremely important, is targeting the healthy cells and tissues that surround and support the tumour. This is an area I am particularly interested in, because if we can understand the environment around the tumour then we can pin it down and control the disease.

How well placed is the UK to tackle these challenges?

I think there are a number of fantastic characteristics that make the UK the best place for cancer research. I firmly believe that the people working at Cancer Research UK are an incredible weapon against cancer, for two reasons. One is their amazing ability to fund groundbreaking research. And the other is that they are always engaging with the research community and are committed to finding the most innovative new research and ideas.

I sometimes think the UK can be a little down on itself, and we occasionally doubt our own ability to accomplish things.

When I was a young scientist I was rather depressed by the excuses that I heard in Britain about why we cannot do certain things. The reality is the UK has fantastic science, great health care professionals and great partners like Cancer Research UK.

There is absolutely no reason why we can’t lead the world in identifying new treatments for children with cancer.

• Find out more about Cancer Research UK Kids & Teens campaign, raising money for research into cancers affecting children, teens and young adults

Interview by Alan Worsley, Cancer Research UK