The rise of bowel cancer in a younger population

Bowel cancer is the fourth most common cancer in the UK, with around 40,000 new cases every year.

Bowel cancer becomes more common with advancing age and the highest incidence is in people in their 80’s. However, in recent years, despite an ongoing decline in bowel cancer incidence in the UK overall, there’s been a clear increase in younger people in their forties and younger. In the UK the rate of bowel cancer in the under 50’s has increased by around 50% since the mid-1990s. 

But what is driving this change and what can younger people do to reduce their personal risk?

Mr Alastair Windsor, Consultant Colorectal Surgeon, Director for Cancer Surgery and Chairman of the GI Tumour Board at HCA Healthcare UK, explains the theories behind the age risk factor change and gives his advice on how best to manage this increased incidence and risk.

In the past thirty years we have seen significant change in the age of people in our bowel cancer clinics. Traditionally we mostly saw people in their 60’s, 70’s and 80’s with bowel cancer but began to recognise that our patients were getting much younger. It’s still very common in those older age brackets, but we were beginning to see more and more younger people and this change has continued over time.

Why should that be, what is causing that? The truth is we don’t know definitively and research is ongoing, but there are a number of theories.

Theories behind the increase

There are multiple factors that can affect your risk of developing bowel cancer, including your age, your genetics and your lifestyle. The changes are so widespread that it is highly unlikely to be a change in genetics, which means the variable that must be driving this change is environment and lifestyle. 

Changes to the microbiome or bacteria in the gut
One theory is the hygiene theory, that when we are young we need to colonise our guts, we need to get certain bacteria into our digestive system which is essential for the normal development of many organ systems. In the 21st century we have become increasingly ‘clean’ conscious, everything is far more sterilised and disinfected than it was previously. This means that our guts aren’t exposed to the same levels of bacteria they once were, and we aren’t colonising our digestive system in the same way; we don’t have that garden in the gut, which is hugely important to health. Added to this lack of colonisation is an increase in damage to the gut bacteria from the over-prescribing of antibiotics in modern medicine.

A dramatic change in diet 
The biggest factor has to be diet, our diet has changed a lot in the past 50 years. We are eating more processed foods, too much fat, too much sugar and too little fibre. What we eat has a huge impact on our digestive health as it can affect the microbiome, which is the community of bacteria that lives in our digestive system and contributes to our health. It’s that interaction with the bacteria, and change to the balance of bacteria in our digestive systems that seems to drive many different diseases. Most obviously it is driving digestive disease such as cancer, inflammatory bowel disease and irritable bowel syndrome.

Research is ongoing into exactly how these different factors may have contributed to the increase in early bowel cancer, and to what degree, but it’s safe to say that diet is playing an important role in this change. 

What we do know definitively is that what we eat, combined with a lack of exercise, can lead to being overweight or obese, which is a proven risk factor for cancer in adults. In fact, being overweight or obese is the UK’s biggest cause of cancer after smoking. Children and young people get less exercise today than they used to and they also spend more time sitting down.

A family history of bowel cancer

There is another group of younger people, around 5%, who are at risk of developing bowel cancer at a younger age based on an inherited genetic risk, also known as a hereditary risk. This means they may have an increased risk of developing bowel cancer based on a history of cancer in their family. Specifically, if they have two or more close relatives from the same side of their family who have been diagnosed with bowel cancer under the age of 50, they may have an inherited genetic condition.

Mitigating the risk

Whilst you can’t change your age or genetics, knowing your family history and making certain lifestyle changes can significantly reduce your risk of bowel cancer.

Knowing the signs and symptoms of bowel cancer
The key to recognising colon cancer is to look for changes in symptoms and persistence of symptoms. The most common symptoms of bowel cancer include:

• An unexplained and persistent change to bowel habits, for example towards a looser or more frequent stool, particularly that persists for weeks rather than days
• Blood in the stool, or bleeding from the bottom
• Unexplained weight loss
• Fatigue – extreme, unexplained tiredness
• Pain in the stomach or a noticeable lump in the stomach

Many other health problems can cause similar symptoms but it’s highly important to get any concerning symptoms checked and diagnosed to rule out colon cancer. The big message is just be careful, just because you’re young don’t assume it’s a benign disease, it’s inflammatory bowel disease, irritable bowel syndrome for example; it may well be, it’s extremely common, but be cautious. There’s no doubt that if we can diagnose bowel cancer early, we have a much better chance of curing it.

Making positive lifestyle changes
If you’re an adult of any age, maintaining a healthy weight, engaging in regular physical activity, cutting down on red and processed meat (such as bacon and sausages) and eating more wholegrains and foods high in fibre can reduce your risk of certain cancers, including bowel cancer.

Being aware of your family history
If you have a known history of bowel cancer in your family and are concerned about your risk of developing bowel cancer, you might benefit from visiting a consultant geneticist to better understand your personal risk and the options available to you.

At HCA Healthcare UK we have highly experienced consultants in clinical genetics who specialise in assessing risk for inherited conditions and helping to manage genetic disorders.

If you are diagnosed with one of these genetic conditions, risk-reducing strategies, such as increased screening, means that many of these cancers can be avoided or caught at an early stage.

Learn more about hereditary cancer and genetic testing

Remember, if you have any new, persistent, or unusual symptoms, or you feel something is wrong, even if it is not mentioned in this article, do not delay in speaking to your GP.

To learn more about bowel cancer diagnosis, treatment and care and the services available at HCA Healthcare UK, please visit our dedicated bowel cancer page