Sometimes I wonder how some papers actually make it through the peer review process. A study of Egyptian mummies and ancient skeletons has found little evidence that they suffered from cancer. The authors of the study suggest that this means cancer is a modern disease. (1) “This might be related to the prevalence of carcinogens in modern societies,” write Rosalie David of the University of Manchester, UK and Michael Zimmermann of Villanova University, Pennsylvania. Cancers, they add, are “limited to societies that are affected by modern lifestyle issues, such as tobacco use and pollution resulting from industrialization”. What a load of crap!
The assertions have dismayed many cancer researchers, and have led to a rash of uncritical coverage in the popular press. So what should we make of the evidence from the mummies, and do they justify laying the blame for cancer firmly on modern society?
In a review of published analyses of tens of thousands of ancient skeletons and hundreds of mummies, David and Zimmermann found only a handful of cases of cancer. One recent finding, of colorectal cancer, was identified as the first ever discovered in a mummy. They also examined ancient texts and literature from Egypt and Greece, and say that there’s little sign that cancer was a common ailment. Upon this analysis, thay make the outlandish suggestion that cancer is largely a modern disease.
In a press release put out by the University of Manchester David is quoted as saying, “There is nothing in the natural environment that can cause cancer. So it has to be a man-made disease, down to pollution and changes to our diet and lifestyle.” Believe me, I am nor alone in my consternation of so idiotic a statement. There are dozens of natural causes of cancer, including ultraviolet light from the sun, natural radiation from radionuclides such as radon in rocks, cosmic rays, and infection by viruses that trigger cancer, such as the human papilloma virus, which causes cervical cancer and hepatitis viruses that can cause liver cancer. Likewise, soot and smoke from fire contain a multitude of carcinogens, as do fungal aflatoxins. And that doesn’t even include cancers with a genetic link.
Certainly there are elements of modern life that cause cancers, but most of them are down to poor lifestyle choices that people can do something about, not, as implied, because they are drowning in a sea of carcinogens from which there is no escape.Smoking is the most significant of these, causing around a quarter of all cancers globally. Other major lifestyle factors that pose cancer risks include heavy drinking; which can lead to liver and gullet cancers; excessive sunbathing by fair-skinned individuals, which can lead to skin cancer; and obesity and lack of exercise, which can promote cancers of the gut.
The study is flawed in so many ways that it really is embarrassing. Almost all the mummies and skeletons included in the study were of people who died before the age of 50. Ageing is one of the major causes of cancer. The authors claim that because they found evidence for other diseases of ageing, such as arthritis and hardening of the arteries, that cancer should therefore have shown up too. Where have these people been? The morphological changes associated with both of the afflictions occur years and decades before symptoms or debilitation occurs. Autopsies done on physically fit American soldiers who died in combat have found signs of hardening of the arteries in nearly all cases. In contrast, in men today, 90 per cent of cancers occur after age 50. If you examined the bodies of 1000 modern men who died before 50, you wouldn’t find many cancers either.
Just a thought, but I wonder what these two researchers would have to say about the prevalence of tumors in fossilized dinosaur bones. (2)
Anyway, in the study, one of the main arguments for cancer being an affliction of modernization was the apparent lack of evidence for “common” bone cancers in children. But again, the figures don’t bear this out. Bone cancers in children are relatively rare, affecting about 1 in 10,000 children. Even if you have 10,000 childhood mummies, you’d be lucky to find a single case!
Because of so much backlash, particularly from cancer researchers, David has backpedalled a bit. “We’re not saying what the explanation is, we’re proposing its modern living also taking into account that people living longer might be to blame,” she says. Cancer support groups and charity organizations are not very happy with this junk science. Their big fear is that by blaming industrialization generally for cancer, it will make people feel helpless about the situation, and divert attention from the many changes they can make to their behavior to reduce their risk, such as quitting smoking, exercising more, drinking less and eating more healthily.
- David, Rosalie and Michael Zimmerman. 2010. Cancer: an old disease, a new disease or something in between? Nature Reviews Cancer, 10: 728-733.
- Rothschild, D. H. et al. 2009. Epidemiologic study of tumors in dinosaurs. Naturwissenschaften, 90 (11): 495-500.