After all, cancer is really a matter of chance?

A survey published at the end of last year caused controversy by claiming that the “bad luck” is one of the factors that cause most cancer, more even than known risks, as the habit of smoking.

Since then, there has been a wave of criticism of the American study, conducted by researchers at the Johns Hopkins University and the Bloomberg School of public health. Some of the criticisms were directed to researchers. Other, to reporters. Then the articles about the study exaggerated? What they should have said?

Most of the headlines at the time revolved around something like “most cases of cancer is caused by simple bad luck”, including BBC India.

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Initially, to understand the study, published in the journal Science, it helps to understand the basic science behind cancer.

The disease occurs when cells in a specific part of the body begin to mutate and reproduce uncontrollably. Cancer cells can invade and destroy tissue.

Environmental factors

Johns Hopkins researchers claimed to have found a correlation between the number of cell division that occurs in a given tissue and the likelihood of it becoming cancerous.

They analyzed 31 types of fabric. To P Z Myers, a biologist at the University of Minnesota, in the United States, “some were fairly stable, as the muscular and cerebral, not divide when they stop developing”.

— So, they have a low probability of developing cancer, while the epithelial lining of the intestine is constantly regenerating. And these cells have a higher probability of becoming cancerous.

If you smoke, you increase the chance of having lung cancer. Other behavioral and environmental factors are known to cause this and other types of cancer.

But some people who do not smoke also develop cancer. In addition, other environmental and genetic factors have no impact on other cancers.

So, how many cases of cancer are caused by a random error in cell division?

The researchers say that this percentage were calculated and came to the conclusion that two thirds (65 percent) “the differences in risk of developing cancer in different tissues” is due to the cell divisions that went wrong, i.e., “bad luck”.


Many vehicles have concluded that this meant that two thirds of cancer cases were the result of a disordered cell division. That’s not what the research said.

However, for many, it is not clear what research says exactly.

To the 65% refer exactly? The most likely explanation is that the researchers referred to the correlation between cell division in different types of tissue and the trend of this material to develop a cancer.

Criticisms from all sides

If you imagine a graph, would have all the different types of cancer with the frequency of Division into one of the axes and the frequency of cancer in the other.

If the points were scored by the entire chart, you would say that there is no relationship between cell division-what researchers call bad luck-and the cancer.

Journalists were criticized for giving misleading ‘ headlines ‘ on the American study

And if all points if aligned perfectly, there would be 100 percent correlation between cell division and cancer.

The answer that the investigators found it is somewhere in the middle of those two possibilities: the points on the graph line up reasonably, then the rate of cell division is 65% cancer rate related.

But, if that is correct, would also criticism on the method of research.

The study authors were unable to give an interview to the BBC, but said they are writing a technical study to clarify the initial study.

So who do you blame for the confusing headlines? The epidemiologist George Davey-Smith, of the University of Bristol, argues that you can’t blame journalists of sites, TVs and newspapers of major media.

The headline of the own magazine publishing Science, he remembers, was “the bad luck of cancer”, and then read: “analysis suggests that most cases cannot be prevented.”

— So it’s not fair to blame journalists – they just copied what the magazine and the realease said.

But if the headlines were misleading, the study also underwent the same criticism, Second P Z Myers.

— The importance of the study is that he says, Yes, that if you have cancer, you shouldn’t blame yourself for it. And I think this is something that people who have cancer, would love to hear.