August 2011 podcast transcript

This month - bowel cancer risk doubles for men; weight has a hefty impact on cancer-causing hormones in older women; a sponge on a string could help oesophageal cancer screening; we announce a new project aimed at cracking the cancer code; and we take a closer look at rising middle-aged cancer rates.

Welcome to the Cancer Research UK podcast. I’m Paul Thorne.

Men’s chances of getting bowel cancer have doubled since the mid 1970s, according to new figures from Cancer Research UK. This means that an average man now has a one in 15 chance of developing the disease.

The figures are based on a new method of predicting the lifetime risk of getting cancer, developed by Cancer Research UK statisticians.

Catherine Thomson, one of the team involved in the research and head of statistical information at Cancer Research UK, explains more.

“The statistics do seem to be showing that the risk of getting bowel cancer in men has doubled, so it’s gone from 1 in 29 men to 1 in 15 over the last generation. And for women the risk is now 1 in 19.

But the good news is that though the risk of getting cancer has doubled in the last generation, survival has also doubled in the same time period. So although more people are at risk of getting bowel cancer, we know that if you do get it you’ve got a much better chance of surviving now that you would 30 years ago.”

Cancer Research UK has launched a clinical trial to test a new device for detecting Barrett’s oesophagus – a condition that increases the risk of developing oesophageal cancer.

The test, called the Cytosponge, is a capsule on a string that expands into a small sponge when swallowed. As the sponge is gently pulled out, it takes a sample of cells that can be tested for signs of disease.

If successful, the trial could pave the way for a national screening programme to try and bring down rates of this deadly form of cancer.

Dr Kat Arney, science information manager, tells us what impact this test could have on detecting the disease.

“Barrett’s oesophagus is a relatively common condition in which the cells lining a person’s oesophagus or gullet change to become more like stomach-lining cells, usually as a result of acid reflux or heartburn as it’s known. In a very small number of cases, these changes can go on to become oesophageal cancer.

At the moment, people with Barrett’s oesophagus are monitored using a technique called endoscopy, which involves putting a tube down their throat. It’s not a particularly pleasant thing to have done, so this new sponge on a string could be a really good alternative for keeping an eye on any cancerous changes, as it’s much less invasive.

It’s going to be really interesting to see what the trial results say, to find out whether it could be used as a more widespread screening technique in the future.”

Weight is the biggest preventable factor affecting the levels of female sex hormones that can fuel some types of breast cancer, according to a Cancer Research UK-funded study published in the British Journal of Cancer earlier this month.

In terms of risk, weight was closely followed by alcohol and cigarettes, the researchers found. We asked researcher Professor Tim Key, based at the University of Oxford, to explain more about his team’s findings.

“The reason for doing the research is that we know already from previous work that women with high levels of certain sex hormones – particularly oestrogens – are at increased risk for developing breast cancer. So what we were doing was trying to understand what other factors in relation to the women’s characteristics or lifestyle affect hormones.

We got together more or less all the data that’s available in the world from studies looking at hormones and breast cancer. It was data from 6,000 women coming from 13 studies. The strongest factor in relation to sex hormone levels was the level of obesity, as measured by body mass index.

We found that obese women had much higher levels of oestrogen circulating in their blood than thin women. For total oestradiol – the main female sex hormone – the levels were about 50 per cent higher in the obese women. And for the amount of oestrogen that’s actually free and able to interact with cells, it was about 90 per cent higher. So that was a really big difference.

The other things that we found were related to hormones were alcohol and, to a lesser extent, smoking. Alcohol is a very important topic because we know that alcohol does increase breast cancer risk.

We found that women with a moderate daily intake of alcohol had about 14 per cent more oestradiol in their blood than women who didn’t drink alcohol. So we don’t know why alcohol causes breast cancer, but it could be part of the mechanism.”

Cancer rates in middle-aged men and women in Great Britain have leapt by nearly 20 per cent in a generation – an increase of 17,000 cases a year – according to new figures released this month by Cancer Research UK.

But just because cancer incidence rates in middle-aged people have gone up by nearly 20 per cent in a generation, it doesn’t mean that all cancers are on the rise.

Our reporter Angela Balakrishnan spoke to Jessica Harris, health information manager, to find out how the outlook has changed for different cancers and why.

“Our new research, which has recently been released, has shown a really strong rise in cancer rates in middle-aged people. They’ve gone up by 20 per cent in just one generation. And in women the rise was even stronger – they’ve gone up about 25 per cent in the same time. And interestingly there are different things going on with different sites.

For prostate cancer, for example, they’ve gone up by 6 times in the last 30 years, and for breast cancer they’ve gone up by a half. But on the other hand lung cancer cases have gone down in men of that age by quite a long way, so it’s not all bad news, but rates have been increasing across the board.”

Angela: Why are we seeing this increase in rates?

“For particular cancers like prostate cancer and breast cancer, it’s likely to be down to more and more people being tested or screened for the disease. More and more men are getting a PSA test now, which is going to increase the number of men who are diagnosed with prostate cancer. And for women, breast screening does increase the number of cases that are diagnosed.

But it’s also likely to be down to other things like changes in our lifestyle. For example, we know that more and more people are overweight now that there ever have been before, and that is possibly playing into it as well. As far as lung cancer goes, it’s likely that those rates have dropped as a direct result of men in particular giving up smoking.”

Angela: Is this a worrying trend?

“Although we’re seeing cancer rates going up in all age groups across the board for many years now, that’s mainly due to our aging population. It’s not all bad news though. In parallel with the cancer incidence rates going up, survival rates are on the rise too.

That’s largely down to the research we and other organisations have been doing, which is constantly providing new information about better treatments and better ways of diagnosing the disease. And that all leads to an increased survival rate. In fact survival rates have doubled since the 1970s, and that’s largely down to the work of Cancer Research UK among others.

There’s still a lot more than we need to do to reduce the number of people that die from cancer. The research that we’re doing now will lead to better treatments and higher survival in the future, but we do need to do more. And in order to do that we need more funding. All our research is funded by the generosity of the public, so we’d really urge them to continue supporting us as we make more and more progress against cancer.”

This month, Cancer Research UK launched two pioneering projects to identify the crack the code of oesophageal and prostate cancer, by finding the key genetic faults that drive the diseases.

The projects, which form part of the International Cancer Genome Consortium, or ICGC, will scan the entire genomes of 500 oesophageal and 500 prostate cancers, transforming our understanding of the diseases and paving the way to better and more targeted treatments in the future.

Our reporter Ailsa Stevens speaks to Nell Barrie, senior science information officer at Cancer Research UK, about the charity’s role in what is considered to be the most ambitious genetic research effort since the Human Genome Project.

“What cancer researchers are starting to understand is that every type of cancer is different – and not only every type, like breast or bowel cancer, but actually the individual cancers that patients get are different. So there could be different genetic faults in every person’s cancer that are driving that disease and causing it to spread or to grow or to have the characteristics that it’s got. If we want to understand the disease and come up with the best treatments we really need to understand all those individual changes in different cancers, and that’s what this project is all about.”

Ailsa: And how is the charity contributing to this huge project?

“Cancer Research UK is involved in two parts of ICGC – we’re looking at prostate cancer and oesophageal cancer. These two types of cancer contribute to 17,000 deaths in the UK every single year, so they’re really causing a big problem. We think we can make a really big difference by taking part in this project and contributing to the research.”

Ailsa: What kind of changes will the researchers be looking for?

“The interesting thing about this project is that they’re looking at the full genome of different tumours. So you’re taking samples from prostate tumours, samples from oesophageal tumours, and sequencing the whole DNA from that tumour.

We’re going to be looking at every single part of the DNA, and we’re going to be looking for the faults that you find across lots of different tumours. We’re going to be comparing samples from many tumours from different people and looking for the faults they have in common. And hopefully that will tell us which faults are driving the disease, and which faults we should be focusing on when we’re developing new ways to treat it.”

Ailsa: Why hasn’t this research been possible in the past?

“It’s actually a really interesting time to be doing this work, because we haven’t had the technological capability before. We’ve been able to sequence cancer genomes and genomes of different kinds of cells, but in the past it’s always taken a really long time and been very labour-intensive and expensive as well.

But at the moment we’re starting to get to a point where we’ve got really advanced sequencing machines that can do it a lot more quickly and cost-effectively. And that’s why there’s so much of this research going on at the moment. It’s a really exciting time to be involved with this.”

Ailsa: How long will it be before we start to see results from this research?

“It’s going to take a little while. For the prostate cancer side of the project, we already have all of the samples we need, and we’re going to start sequencing them straight away. But for oesophageal cancer, we actually need to collect some of those samples as part of the work that we’re doing, so that’s going to take a bit longer.

So we’re thinking possibly about 4 years before we get results from the oesophageal cancer project, and hopefully quicker for prostate cancer. We may even get some results within 18 months of the beginning of the project, which is now.”

Ailsa: And, most importantly, how is ICGC going to help people with cancer in the future?

“The whole idea behind this project is to understand these diseases that we’re looking at. Cancer Research UK is looking at prostate cancer and oesophageal cancer. But all around the world there are other researchers looking at 50 different types of cancer altogether.

The idea is that we’re going to find the faults that are driving these cancers, and that’s going to tell us how the disease works, what causes it to grow, what causes it to spread. Really the first stage is just understanding the biology, but all of this is directed towards helping with these diseases and saving lives.

What we’re hoping is that these results we’re going to start getting will give us ideas for new ways to treat these diseases, new ways to diagnose them and perhaps monitor them. And all the information we’re going to get is going to be available to researchers around the world, so everyone can use this knowledge, and hopefully find better ways to treat these cancers and save more lives.”

We’ll be back next month with all the latest news and features. In the meantime, you can keep up to date by reading our Science Update blog.