Cancer Controversies - Cancer Research UK

Food and cancer: why media reports are often misleading

Posted on December 14, 2012 by Sarah Williams

Plate of food (image from WIkimedia Commons)

This research shows the danger of overstating the results of single studies

The media’s appetite for things that cause or prevent cancer can be as notable for its sheer volume as for – in some cases – its hype. And food is a key area of interest, because everyone can relate to the latest headlines on bacon or broccoli.

Rarely a week goes by without headlines on the latest “cancer-busting” food or, at the other end of the spectrum, the unexpected perils of pop. So a research article with the intriguing title ‘Is everything we eat associated with cancer? A systematic cookbook review‘, published in the American Journal of Clinical Nutrition recently, couldn’t fail to catch our attention.

This review looked at a selection of cookbook ingredients to see if they had been investigated for links to cancer. The researchers found that most of the 50 foods they looked at had been associated with an increased or decreased cancer risk in the scientific literature.

But is this a testament to the power of different foods over our chance of developing cancer? Or is it proof that scientists just can’t make their mind up?

In fact it’s neither. The most important finding of the review was that single studies often found links that had only weak evidence behind them.

The research provokes thoughts about why we do research, how much one study on its own can tell us, and the value of considering the balance of evidence.

Perhaps most importantly, is also raises questions about how much detail scientists and the media provide as context when they present results to the public.

And rather ironically, and worryingly, one paper decided this study warranted the conclusion that there is ‘no proven link between foods and cancer’. This is clearly not the case, as we explain below.

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‘Chemical jobs’ – should women be worried?

Posted on November 22, 2012 by Jess Harris

The study behind this week’s headlines had several major limitations

There’s been quite a bit of media coverage this week suggesting that women in so-called ‘chemical jobs’ may face a higher risk of breast cancer, including this story by the BBC.

The headlines were based on a new study published in the journal Environmental Health looking at how likely women in different jobs are to develop breast cancer.

But what did the study really show? And what are ‘chemical jobs’ anyway? We wanted to clear up one or two things about the study, and who is and isn’t at risk because of their job.

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Some thoughts on stress, cancer and beta-blockers

Posted on July 18, 2012 by Henry Scowcroft

Research into stress and cancer has been inconclusive

The topic of stress and cancer is complex, emotional and controversial.

Many people diagnosed with cancer, understandably, want to know whether something that has happened in their lives could have led to their disease. And because many people have stressful lifestyles, they often ask whether stress could have caused their cancer.

The short answer is that it almost certainly didn’t.

The causes of cancer are a complex mixture of lifestyle, environment and genetics, as we wrote last year. And on top of this, population studies repeatedly fail to show a definite, concrete link between ‘being stressed’ and a person’s chance of developing cancer, as we’ll see below.

But the more researchers study the biological processes involved in stress, the more they’ve realised that cancer might subvert some of these for its own ends. And understanding how could yield clues as to how to treat the disease.

So although there’s an emerging link between cancer growth and the molecules involved in stress, this is a long way from saying ‘stress causes cancer’, or makes it worse.

This subtle but important difference was underlined by new research today in the journal PLoS Biology, looking at how stress-linked molecules might be involved in the spread of cancer. Disappointingly, the research was accompanied by a press release that overplayed the evidence on stress and cancer. And this led to some unfortunate headlines.

This is a shame, because the research itself is rather intriguing. It lends even more weight to the idea that simple drugs like beta-blockers might be a useful addition to doctors’ anti-cancer armoury – something our own researchers are studying.

But it would be a shame if this finding were clouded by emphasising the idea that stress causes cancer. People diagnosed with the disease have enough on their plate without being worried about being worried.

Let’s look at how the new research fits into the wider picture.

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Diesel exhaust fumes ‘definitely’ cause cancer – should we be worried?

Posted on June 14, 2012 by Henry Scowcroft

Exhaust fumes have been conclusively linked to lung cancer

Today the International Agency for Research on Cancer (IARC) – part of the World Health Organisation – announced that it had reclassified diesel exhaust as a ‘definite carcinogen’ – putting it in its highest category (Category 1).

In other words, IARC’s expert panel assessed all the available scientific evidence and decided that exposure to diesel exhaust fumes can, and does, cause cancer in humans – specifically lung cancer (although there’s weak evidence they’re also linked to bladder cancer).

But what does this mean in practice? Is this something the general public should be worried about?

We spoke to Professor David Phillips – a Cancer Research UK-funded carcinogen expert from King’s College London – to ask him what he thought of the announcement.

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Night shifts linked to breast cancer in women? Probably – but not definitely

Posted on May 29, 2012 by Sarah Williams

Not enough evidence to say for sure that working night shifts increases breast cancer risk

A Danish study into whether working night shifts could affect a woman’s risk of breast cancer is hitting the headlines today.

But (as is often the case), when you look beyond the headlines, the picture can become a little less clear.

So could working night shifts cause breast cancer? The science says “probably”. But probably can be a bit of a tricky word: it isn’t no, but it isn’t really yes either.

So what’s going on? We’ve covered this issue before on this blog, so what does today’s study add to the picture?

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‘Super’ broccoli – no firm evidence it prevents cancer in humans

Posted on October 6, 2011 by Henry Scowcroft

There's little hard evidence that eating more broccoli prevents cancer

A new type of ‘super’ broccoli, developed by scientists at the Institute of Food Research and the John Innes Centre, has been launched in the UK, leading once again to headlines about the vegetable’s ‘cancer-fighting’ abilities.

The researchers have specially bred the new broccoli, sold as ‘Beneforté’, to increase its levels of glucoraphanin, a chemical which our bodies convert to another, sulforaphane, whose health properties have been heavily scrutinised in the lab.

But how strong is the evidence that eating broccoli – either normal broccoli or this new souped-up variety – can actually prevent cancer? Let’s take a look at what the science says.

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No need to worry about having a shower or drinking water

Posted on March 17, 2011 by Henry Scowcroft

Going for a swim won't give you cancer

“Swimming too often in chlorinated water ‘could increase risk of developing bladder cancer’, claim scientists”.

But did they, or is this another example of misreporting cancer research by the media?

Unfortunately, it’s the latter. This is an example of poor reporting, which makes unwarranted claims about human health. The research itself says nothing new about bladder cancer, and didn’t even involve people with the disease.

Let’s have a look at what’s going on.

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