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If more cancers are caused by bad luck, why are we getting less lucky?
At the start of 2015 the press carried claims from scientists at Johns Hopkins University School of Medicine in the US, that the majority of cancers are NOT linked to environment or lifestyle. These findings conflict with many other findings. If most cancers are caused by bad luck, why, according to World Health Organisation reports in 2014, is the number of cancer cases worldwide on target to increase by 70% over the next two decades? This includes the spread into less developed countries where a Western lifestyle is being adopted.
Read full article by Hermann Keppler, Founder and Principal of CNM (College of Naturopathic Medicine). CNM offers Diploma training courses in Naturopathic Nutrition, and other natural therapies.
January 2015
So is cancer mostly 'bad luck' or not?
Headline-writers and news bulletin editors around the world just couldn't get enough of a new study of cancer published on 2 January. "Two thirds of cancers are due to bad luck" reported one typical news story - and most other media outlets had similar headlines.
But there's been criticism of the way this statistic was reported, some of it directed at journalists, and some at the researchers themselves.
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The researchers weren't looking at what determines why some people get cancer and others don't. They were instead asking why some types of cancer are common and some are rare.
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The researchers from Johns Hopkins School of Medicine in the US reported they had found a correlation between the number of cell divisions that take place in a given tissue and the likelihood that it would become cancerous. They looked at 31 tissue types (two common cancers, prostate and breast cancer, were not considered).
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The researchers say they've calculated that two thirds (65%) of "the differences in cancer risk among different tissues" is down to cell division gone wrong - "bad luck". Now many media reports have simply concluded that this means that two thirds of cancer cases are just the result of random haywire cell division. That's not correct.
Read full article by Ruth Alexander on BBC News.
Are most cancers down to bad luck?
This study estimates around two-thirds (65%) of cancer risk is down to chance, based on the number of times stem cells divide in different body tissues. Other factors, including environmental factors and genetics, account for the remaining risk.
However, the estimate was quite variable, with 95% confidence intervals ranging from 39% to 81%. So only 4 out of 10 cancers may be a result of bad luck, or, alternatively, as many as 8 out of 10.
The wide estimate reduces our confidence in its accuracy. Its reliability would be increased if other research groups arrived at similar numbers by a variety of different means.
Read full article on NHS website.
