02 October 2024
Check Up #26 - Why are younger people increasingly diagnosed with cancer?
They may be ageing faster.
Natural ageing is one of the main risk factors for cancer. As we become older, the probability of developing cancer increases. This happens, on the one hand, because the probability of acquiring cancer-causing mutations grows as we live longer; and on the other, because our DNA repair mechanisms decline with age.
But more and more people under 50/55 years of age are being diagnosed with cancer. For instance, the past decade has witnessed a doubling of colorectal cancers in people under 50/55 years of age – from 5% to 10% of all cases. Just in the US, between 2008 and 2015, this increase was over 60%! This has been puzzling specialists. Risk factors such as bad lifestyle habits have come into the picture to explain this phenomenon.
In fact, the link between early-onset cancer and lifestyle increasingly appears to be “epigenetic” and due to what is being called “accelerated aging”.
Epigenetic changes in DNA are not mutations: they are chemical changes that do not involve alterations to the underlying DNA sequence. One of these processes is methylation, where a small molecule called a methyl group attaches to the DNA strand, which in turn can modify gene behavior, changing the degree to which genes are turned on and off. Epigenetic changes, which are thought to be influenced by factors such as diet, physical activity, mental health, and environmental stressors, can be passed on to children by their parents and even their grand-parents – and it is known that they can lead to cancer by various mechanisms.
This means that younger people may be more frequently getting cancer because they are increasingly becoming… biologically older than their chronological age. Accelerated aging, caused by epigenetic changes induced in part by bad dietary habits and other poor life habits of modern societies, may well be at the basis of the massive increase in cancer cases among younger people, with the emergence of cancer linked not to a person’s chronological age but, rather, to the age of their cells and tissues.
This hypothesis was put forward by a team from Washington University during the 2024 edition of the American Association for Cancer Research (AACR) Annual Meeting.
They stated “that increased biological age, indicative of accelerated aging, may contribute to the development of early-onset cancers, often defined as cancers diagnosed in adults younger than 55 years” – adding that, “unlike chronological age, biological age may be influenced by factors such as diet, physical activity, mental health, and environmental stressors”.
The good news is that the trend in cancer cases in younger people might be reversible or, at least, subject to mitigation. Several lifestyle factors have been identified that might modify epigenetic patterns, such as diet, obesity, physical activity, tobacco smoking, alcohol consumption, environmental pollutants, psychological stress, and working on night shifts.
Will it be possible to determine a person’s biological age? Epigenetic testing, a methodology developed over the last decade, should enable, in the future, the estimation of an individual’s true pace of aging.
