Transcript of audio interview with Dr Lesley Walker, director of Cancer Information at Cancer Research UK, from “Claims that cancer is purely man-made are false and misleading“.

“What’s really incredible about this assertion that there’s so much more cancer now and it’s a man-made disease, is that fundamentally when we look and think about cancer, it’s always been with us. It was actually found in mummies, so cancer was always there.

The key thing about cancer is that we know it gets so much more common in older age. One thing that we absolutely know about ancient populations – including the Egyptians – is that their lifespan would have been much shorter than our lifespan is now.

It’s inevitable that cancer would have been rarer, that it would have been harder to find cancer in those populations. And indeed, one of the major causes of death at a very early age would have been infectious disease in those populations.

When we look at modern populations, one of the things that is absolutely clear is that around two-thirds of cancers occur in people who are over the age of sixty-five.  So, the first question that one would really want to ask is “how old were the people who were mummified when they died?” Was the population of mummies age-standardised?

That’s how we would compare data from across the world and over different time periods. We would take into account the age structure of the population – that’s incredibly important.

And the second assertion, which is just incredible here, is that cancer is a man-made disease – that it’s something about pollution. There have been endless studies pointing out yes, pollution is a factor, but it’s a very small factor. It contributes only a few per cent to the numbers of cancers that develop in any given year and in any given population.

The key risk factor is age, and then after that there are many other external factors that we know about. For example, some of the natural causes of cancer that we know about are UV rays from the sun. There are bacteria and viruses that cause a number of cancers, and account for something like twenty per cent of the cancer burden worldwide.

A number of things that completely go against what’s being said here about cancer being a man-made disease, and pollution being an important factor. Pollution at best accounts for a few per cent of cancers in our population.”