Bowel cancer rises among under-50s in Spain as Mediterranean diet fades, oncology expert warns
Bowel cancer is beginning to rise among younger adults in Spain as the nation’s Mediterranean diet fades, a leading European oncology expert has warned.
Rates are increasing in several countries across Europe, including the UK, Germany, Spain, Italy and Poland, with 25 per cent of cancerous colorectal tumours now found in people under 50, according to Dr Josep Tabernero, the director of the Vall d’Hebron Institute of Oncology in Barcelona.
Scientists are racing to explain this trend, with obesity, abuse of antibiotics, high consumption of alcohol, and changes to the microbiome, the collection of microbes that live in our bodies, all identified as potential factors.
In the case of Spain – and other Mediterranean countries – a change in diet from fresh foodstuffs to processed food could also be responsible, Dr Tabernero believes.
“Spain was somewhat protected because of its Mediterranean diet, with olive oil, vegetables with fibre, and fresh meat and fish, but it has lost this with the American fast-food invasion,” he told The Telegraph.
Dr Tabernero was speaking after research was published showing that the rate of bowel cancer deaths in young people could rise by up to 40 per cent in 2024 compared to the 2014-19 period.
In the UK, women aged between 25 and 49 are 39 per cent more likely to die from colorectal cancer this year, with the increase for men estimated at 26 per cent.
In Spain and Poland, the increase among men was 5.5 per cent and 5.9 per cent respectively, while in Germany the rate among women is predicted to rise by 7.2 per cent. Death rates are predicted to increase in Italy by 2.6 per cent among women and 1.5 per cent among men.
Researchers looking into the causes of colorectal cancer are focusing on possible connections with changes in individuals’ microbiome.
“In our body we have around 4,000 different species of bacteria. This means that of the genome that we have in the body, only 0.01 per cent is human. The remaining 99.9 per cent of DNA and RNA that we have in the body is bacterial,” Dr Tabernero explained.
The Spanish oncologist said that the full nature of the connections between alterations to microbiota in the intestine and bowel cancer has yet to be established.
“But we do know that patients with early-onset colorectal cancer have a microbiome that is different from that of the normal population and from those who develop colorectal cancer at an older age.”
Dr Tabernero said factors such as diet, obesity and antibiotic consumption influence the composition of the microbiome.
“With antibiotics, it is important that these drugs are taken only when necessary because abuse has many consequences and not only increasing bacterial resistance. Doctors are partly to blame for prescribing antibiotics without a proper thought process and the public too, as people self-medicate when they shouldn’t.”
Mysteries of the microbiome
Last autumn, Dr Tabernero took over as chairman of the consortium Cancer Core Europe (CCE), in which Barcelona’s Vall d’Hebron, Cancer Research UK’s Cambridge Centre and five other European institutes pool expertise and research findings to accelerate breakthroughs in cancer treatment and prevention.
CCE is taking part in Optimistic, an international project in which institutions are working together to understand how changes in the microbiome contribute to the development of cancer and the disease having a more aggressive prognosis.
Researchers have identified the link between one bacteria in particular, Fusobacterium nucleatum, with several types of cancer including breast, colorectal, and head and neck cancers.
F. nucleatum exists in the mouth and plays a role in gum disease. Poor oral hygiene associated with under-40s due to factors such as sugary diets and vaping is promoting the growth of this strain of bacteria amongst the young.
Research has shown that when these microbes enter early-stage tumours, they can actively interfere with chemotherapy and radiotherapy, enabling the cancer to grow and spread.
So what can be done about the rise of bowel cancer cases among the young?
Dr Tabernero said that education is crucial so that more people avoid the lifestyle choices that increase risk factors, including high alcohol intake, and also so that the under-50s take the danger of colorectal cancer seriously and do not ignore warning signs such as blood in faeces.
The increased rate of bowel cancer among younger people also has implications for screening programmes, which typically start at 50.
“I think the age of screening will be lowered,” he said. “There are already countries that have a higher incidence of colorectal cancer in young people, such as the US and Canada, that are lowering the starting age to 45 and I think we will end up having to lower it even more.”
As well as new treatments that are improving survival rates for cancers, Dr Tabernero said that earlier detection from simple blood tests, known as liquid biopsies, will become a key tool in the fight against cancer.
“Liquid biopsies will transform how we detect cancer. Tumours secrete fragments of DNA and that altered DNA can be detected in the blood. If you think about pancreatic cancer, which has no symptoms, this will make a huge difference as we can detect a tumour when it is still microscopic.”
At Vall d´Hebron (VHIO), doctors have developed a liquid biopsy application for breastfeeding mothers’ milk to detect breast cancer; tumours in the lactating breast are much harder to detect through scans due to the dense, inflamed state of the tissue.
The VHIO has also been involved in the development of an AI tool that enables a more accurate diagnosis of brain tumours with MRI scans, avoiding the need for exploratory surgery.
The deep learning system has been trained to develop an algorithm that can differentiate between the three most common types of brain tumour – each of which requires different treatment – with 78 per cent accuracy, a higher rate than that of conventional methods.
“The application of AI to radiomics is going to change the way we diagnose patients,” said Dr Tabernero.
“When you use a CT scan or an MMR, a normal human radiologist uses less than five per cent of the information produced by that scan. So imagine if you are able to use 100 per cent of the information that the machine generates. We will be able to diagnose without biopsies of any kind.”
Dr Tabernero said that AI applied to scans also allows for an indication within 24 hours of administering an anti-cancer drug of whether that particular treatment is going to be effective in the long term.
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