22 June 2018

Do you know what causes cancer?

Wrong ideas about what causes cancer can lead to unnecessary worry and even inhibit good prevention and treatment decisions.

In South Africa, where cancer numbers are alarmingly high, it is important to have an informed population. 100 000 South Africans are diagnosed with cancer each year according to Cancer Association of South Africa (CANSA). 

With statistics like that, it is easy to see why education around cancer and its causes is imperative. 

Many people are clueless about what can actually cause cancer, finds a new study funded by Cancer Research UK. The findings were recently published in the European Journal of Cancer. Not stress, microwave ovens or food additives, British experts say. 

According to a survey of more than 1 300 people in England found many people believe otherwise. "It's worrying to see so many people endorse risk factors for which there is no convincing evidence," said study author Samuel Smith, of the University of Leeds.

What are the misconceptions? 

More than a third wrongly believed that electromagnetic frequencies and eating genetically modified food were cancer risk factors. Others believed microwave ovens (19%) or drinking from plastic bottles (15%) caused cancer, despite a lack of scientific evidence. The researchers also found that more than four out of 10 thought stress or food additives caused cancer. When it came to known causes of cancer, 88% of respondents correctly said smoking, 80% cited second hand smoke, and 60% said sunburn.

People who had mistaken beliefs about the causes of cancer were not more likely to have risky lifestyle habits. But those who knew more about proven causes of cancer were less likely to smoke, according to the study.

"Compared to past research it appears the number of people believing in unproven causes of cancer has increased since the start of the century," Smith said in a Cancer Research UK news release. It could be related to changes "to how we access news and information through the internet and social media," he speculated. "It's vital to improve public education about the causes of cancer if we want to help people make informed decisions about their lives and ensure they aren't worrying unnecessarily," Smith added.

Image credit: Istock


Ask the Expert

Cancer expert

CANSA’s purpose is to lead the fight against cancer in South Africa. Its mission is to be the preferred non-profit organisation that enables research, educates the public and provides support to all people affected by cancer. Questions are answered by CANSA’s Head of Health Professor Michael Herbst. For more information, visit

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