Cancer Research UK : Making sense of cancer news and mixed messages

Making sense of cancer news and mixed messages

Who do we believe?

Stories about cancer and its risk factors are common in today’s press. But the messages in these stories can sometimes be confusing. Most things under the sun (and even the sun itself!) have at some point been said to either cause cancer or protect us from it.

This page will tell you more about why cancer stories can be confusing and how you can separate fact from fiction.

Why is there confusion?

Not all scientific studies have equal merit and this can cause confusion. Some studies are well designed and produce accurate and reliable results. Others are less carefully designed, their results may be down to chance and their conclusions may be incorrect. But the media may report both kinds of studies, and it can be difficult telling them apart.

In particular, studying links between lifestyle factors and cancer is very difficult. Scientists can’t carry out experiments on people like they can on cells or chemicals. For example, we couldn’t get a group of people to adopt unhealthy lifestyles for a year and compare them with a healthy group. Instead, scientists have to look at large numbers of people and try to spot links between obesity increases the risk of cancer, for example. You might think that they could just compare cancer rates in obese people with rates in people with a healthy bodyweight. But it isn’t that simple.

Obese people are more likely to be inactive and eat poor diets, both of which can independently increase their cancer risk. So epidemiologists must be very careful to account for other factors that could affect their results.

Strength in numbers

Because of these difficulties, studies need to be repeated to see if the same results are found. If lots of studies agree on a conclusion, it is more likely to be accurate. For example, the links between smoking and lung cancer have been proven in hundreds of studies since the 1950s.

Sometimes, ‘one-off’ pieces of research are reported in the press. Even if these studies were well conducted, the results usually need to be confirmed by other scientists.

What makes a good study?

So how can you tell whether a study is good and whether a risk is ‘real’ or not? There are a few things you could bear in mind when you read or hear a cancer news story. For example, the more people involved in a study, the more accurate it is likely to be. If fewer than 100 people were involved, the results may be due to chance and may not be accurate.

And for complex lifestyle factors such as diet, studies often require several thousand people to produce meaningful results. For example, Cancer Research UK is funding the UK arms of the large EPIC study, which looks at the links between diet and cancer in half a million people.

The ‘Understanding Risk’ section of this website contains detailed information on the factors which can separate the best studies from the weakest ones.

Not just statistics

It’s not enough for scientists to discover links between lifestyle factors and cancer risk. They must also understand the biology behind those links, as they now do for smoking.

Scientists have shown how certain chemicals in cigarettes can damage our DNA, and how this damage can lead to cancer. These findings back up results from epidemiological studies, and help to conclusively show that smoking causes cancer.

Getting some perspective

Even if something is definitively shown to cause or protect against cancer, we have to consider the size of its effect. For example, if you are a smoker and want to reduce your risk of lung cancer, eating more fruit may have an effect – but not nearly as big an effect as giving up smoking.

Cancer Research UK gives you information you can trust

The best way to confirm if something you have read is accurate is to check a reliable source of information.

If you see or hear a cancer story that leaves you confused or wanting to know more, have a look at one of our websites or resources. Cancer Research UK is committed to providing the most accurate and up-to-date information possible on cancer, and how to reduce your risk.

The information and advice on our websites is based on strong scientific research. We continuously and carefully assess the current evidence, with advice from our top scientists and other experts.

Our Information Resource Centre contains lots of information about cancer, the healthy choices that could reduce your risk of the disease, and the behind this information.

Our CancerHelp UK website provides comprehensive information for cancer patients.
And we have a wide range of cancer awareness leaflets, cancer statistics, briefsheets about our research, and resources to accompany our awareness campaigns.