Cancer rates accumulating over generations

Cancer rates accumulating over generations

Jack Baker, ECU Reporter

New research from the University of Adelaide has suggested that the higher rates of cancer seen in developed countries are a result of relaxed natural selection.

After cardiovascular diseases, cancer has become the second highest cause of death worldwide. While tobacco smoking, diet and pollution associated with increased urbanisation have all had an effect on growing cancer rates, our own success in treating cancer may be having its own impact.

Co-author of the paper and a comparative anatomy and human evolution expert at the University of Adelaide’s medical school, Professor Maciej Henneberg, said in a media release from the university that modern medicine has allowed the human species to survive much longer than would otherwise be expected naturally.

“Besides the obvious benefits that modern medicine gives, it also brings with it an unexpected side-effect: allowing genetic material to be passed from one generation to the next that predisposes people to have poor health, such as type 1 diabetes or cancer.

“Because of the quality of our healthcare in western society, we have almost removed natural selection as the ‘janitor of the gene pool’.

“Unfortunately, the accumulation of genetic mutations over time and across multiple generations is like a delayed death sentence,” he said.

The study compared the countries that have the highest and lowest opportunities to survive cancer. Wenpeng You, Co-author and PhD student at the University of Adelaide, said in the release that determining these countries took mortality and fertility rates into account (a hallmark of more developed countries), in addition to socioeconomic status, urbanisation and quality of medical services.

“Countries with low mortality rates may allow more people with cancer genetic background to reproduce and pass cancer genes/mutations to the next generation.

“Meanwhile, low fertility rates in these countries may not be able to have diverse biological variations to provide the opportunity for selecting a naturally fit population, for example, people without or with less cancer genetic background.

“Low mortality rate and low fertility rate in the ‘better’ world may have formed a self-reinforcing cycle which has accumulated cancer genetic background at a greater rate than previously thought,” Mr You said.

This is not to say that life is necessarily better in a less-developed country, if you’re trying to avoid cancer.

A 2015 study in the Cancer Epidemeology Biomarkers & Prevention journal found that while high-income countries continue to have the highest incidence rates of cancer, the mortality rates have either declined or are plateauing due to greater knowledge of risk factors and early detection, while low and middle-income countries have seen rates increasing for certain cancers due to increases in smoking, excess body weight, and physical inactivity.

But don’t sit around and blame your forebears if something happens. A study published in the Nutrients┬ájournal found the majority of cancers found around the world are caused by the behaviours that we already know to be bad for us: smoking, eating meat and drinking alcohol.

For information and support on cancer call Cancer Council Australia on 13 11 20.