By Barry Lord @Bazneto
Cancer is a complicated disease. As human beings, we’re born with a certain number of genetic aberrations that can lead to the disease, and how we live, our genetics and the environment we live in/work in can have a say in whether or not we will be exposed to the disease in our lifetime.
Cells continue to divide as we get older and they’re more likely to make genetic mistakes when they copy our genome. It is these mistakes that can lead to tumours.
But just how many cancers are known to be caused by environment and or/lifestyle choices is a debate that continues to rage.
And here, two professionals in the field have offered their viewpoint based on research.
Researchers from Johns Hopkins caused a stir in the medical world last year when they estimated that well over half—65%—of cancers are actually traceable to random mutations and therefore mostly medical control.
A new study adds to those findings. In a report published in JAMA Oncology, a team led by Mingyang Song, a research fellow at the Massachusetts General Hospital and Harvard T. H. Chan School of Public Health, studied more than 135,000 men and women and determined that lifestyle factors, like diet, smoking and exercise, account for 20% to 40% of cancer risk.
Song agreed with much of last year’s findings but he would not concede the fight against preventable forms of cancer is lost.
Speaking to Time, Song said: “In terms of variation of cancer risk across different tissues, I think stem cell division and random mutations do play a role in cancer development. I wouldn’t interpret their results as evidence that we cannot prevent cancer and there is no way to prevent most cancer because it’s random. I wouldn’t interpret their findings that way.”
The findings seem to support the theory that everyone has some base level of cancer risk that’s caused by their cells dividing, and the mistakes that those cells make when they copy themselves.
On top of that are the lifestyle choices that Song identified —smoking, diet and physical activity — that can accelerate or slow down the level of mutations that stem cells create.
However, Bert Vogelstein, professor of oncology at Johns Hopkins, looks at the debate another way. While focus remains on cancer that is preventable, he and his colleague Cristian Tomasetti focused on the remaining 60% to 80% that isn’t. The professor’s belief is that a patient hitherto healthy and living an active lifestyle is entitled to seek the reasoning behind their diagnosis.
Professor Vogelstein said: “Our study doesn’t address the preventable cases. What our study tries to explain is all cancers that occur in a low risk group, or at least some fraction of those cancers. Before our paper, people thought it was something we couldn’t explain. We explained it; it’s not some previously undiscovered mutagen that’s present in the environment. It’s something very specific that can be measured precisely.”