This research counters ‘mostly bad luck’ cancer risk study

Posted at 12:20 PM, Dec 17, 2015
and last updated 2015-12-17 13:09:41-05

Developing cancer involves a lot more than experiencing a bit of “bad luck.”

That’s what the authors of a new study in the journal Nature argue, challenging the findings of research that came out earlier this year. External factors such as exposure to toxins and radiation are a major risk factor in developing cancer, the new study says.

“Environmental factors play important roles in cancer incidence and they are modifiable through lifestyle changes and/or vaccination” the authors write.

Looking at the increasing incidences of various types of cancers, including lung cancer, the authors concluded that “large risk proportions for cancer are attributable to changing environments” such as smoking and air pollutants.

This latest study runs counter to research that came out earlier this year in the journal Science. That research, from Dr. Bert Vogelstein, a prominent geneticist, and biostatistician Cristian Tomasetti — set off a public health debate about the nature of cancer.

Applying statistical theory, Vogelstein and Tomasetti argued that only about one-third of the cancer risk in adults could be attributed to heredity or environmental factors. “The majority is due to ‘bad luck’ that is random mutations arising during DNA replication in normal, noncancerous stem cells,” the study said.

Essentially, the more often a cell divides in tissue, the more likely it is to develop cancer. An unhealthy lifestyle, for instance if you smoke, use the tanning bed, are overweight, all of that does make matters worse, but it is not the biggest factor.

“Changing our lifestyle and habits will be a huge help in preventing certain cancers, but this may not be as effective for a variety of others,” co-author and medical statistician Tomasetti said at the time.

The authors argued that their study could help the community better understand the disease but also design better strategies to fight cancer.

Their widely reported paper stirred controversy in the scientific community. The World Health Organization’s International Agency for Research on Cancer issued a press release that said the agency “strongly disagrees” with the conclusion of the report. It said “concluding that ‘bad luck’ is the major cause of cancer would be misleading and may detract from efforts to identify the causes of the disease and effectively prevent it.” Nearly half of cancers, the agency argued, could be prevented if people changed their lifestyle or reduced their environmental exposure to cancer-causing agents.

The Vogelstein-Tomasetti study did leave out breast cancer and prostate cancer when it ran its calculations, but a press release from the university that further explained that choice said that the authors were unable “to find reliable stem cell division rates in the scientific literature” and hoped other researchers would develop that data.

To leave out cancers that are known to be influenced by outside factors could have skewed the numbers and the study’s conclusion, other experts argued.

In rerunning the numbers that are available on cancer, this latest research used four different approaches to estimate the causes of cancer. Their work including computer models, genetic evaluation and population data to conclude that only 10%-30% of cancers started because of this “bad luck” factor. The greater majority of cancer is due to outside factors.

Bottom line: If you smoke or are overweight or use a tanning bed, your odds of remaining cancer-free have not improved. In other words, don’t blame “bad luck” for getting sick. You can do a lot to reduce your cancer risk.