Last year, speakers at the annual meeting of the American Society of Clinical Oncology, the world’s most important cancer conference, came with a dire warning.
They noted that rates of colorectal cancer are rising rapidly in those in their under-40s, such that cases in this age group are expected to double by 2030 and that the disease will become the number one source of cancer deaths in those aged 20-49. year-olds by the end of the decade.
Researcher Dr. from the Quadram Institute in Norwich. “Studies show this increase in early-onset colorectal cancer,” says Dimitra Lamprinaki. “The problem is that some of these cases are asymptomatic, but at the same time young people are potentially ignoring signs of cancer that may progress and then be difficult to eliminate.”
This is part of a general trend. Global cancer cases in under 50s are increasing rapidly; According to recent research, it increased by 79 percent between 1990 and 2019. But while lifestyle factors like millennials’ highly processed diets and excessive alcohol use are likely to blame, scientists have discovered an important new connection: microbes fueled by these bad habits, which then lead to more aggressive and treatment-resistant cancers.
Here are some of the main factors that may lead to increased cancer cases in young people.
Electronic cigarettes and poor oral hygiene
London-based private practice Pure Periodontics has witnessed a surprising increase in gum disease in young patients. They link this to sugar- and acid-laden diets, as well as increased vaping in under-40s; This habit blocks blood flow to the gums, increases susceptibility to infections, and makes healing difficult.
All of this promotes the growth of a certain type of bacteria called bacteria. Fusobacterium nucleatum (F. nucleatum) It has been linked to a number of cancers, including breast, colorectal, and head and neck cancers.
“It’s a very sticky bug that sticks to the surface of the teeth and gums, allowing other bad bacteria to get in,” says Dr Tim O’Brien, medical oncologist and researcher at Queen’s University Belfast.
If oral hygiene is poor, these bacteria can multiply, enter the bloodstream and reach different organs. When these microbes enter early-stage tumors, they can actively interfere with chemotherapy and radiotherapy, allowing the cancer to grow and spread.
“Fusobacterium may contribute to radiation resistance as well as chemotherapy,” says O’Brien. “It thrives in the tumor environment, so it’s in its own interest for the tumor to survive. So it interferes with the process by which chemotherapy causes cancer cells to self-destruct, and it can also drive out the immune cells that are trying to destroy the tumor.”
High consumption of processed meat
According to the journal Nature, one of the sharpest increases in cancer rates in under-50s was in stomach cancer.
One of the most known risk factors of stomach cancer is bacteria. Helicobacter pylori (H. pylori) It is thought to be responsible for around 40 per cent of cases in the UK. H. pylori It lives in the mucosal layers lining the stomach and contributes to conditions such as atrophic gastritis, chronic inflammation and thinning of the stomach lining, which can later progress to cancer.
Studies have shown that a diet rich in processed meats such as sausages, bacon and hamburgers may increase the incidence of this disease. H. pylori In the stomach.
Professor Andrew Beggs, Consultant Colorectal Surgeon at the University of Birmingham, describes the link between such microbes and lifestyle factors as ‘vital pieces of a puzzle’.
“You have these bacteria and an unhealthy lifestyle that includes excess red meat, alcohol and smoking, and some people may also have an element of genetic predisposition that increases their risk,” he says. “When you add up all these factors, it leads to a huge increase in cancer risk.”
oral sex
It is not only bacteria that cause cancer cases, viruses are also associated with different forms of the disease. Experts in the United Kingdom have announced rising rates of oral cancer, especially in people aged 40 to 49, and that half of these cases are linked to a form of the sexually transmitted human papillomavirus (HPV), known as HPV-16. through oral sex.
One possibility is a greater number of casual sexual partners; A study in the journal Cancer finds that kissing, and especially deep kissing, is also linked to increased risk, with individuals who have 10 or more deep kissing partners being twice as likely to develop HPV. -associated cancer.
ultra-processed foods
F. nucleatum Bacteria not only make cancers more resistant to treatment, they can also actively trigger the disease, especially in the gut. A new study Nature Research published last week found that mice given a specific subtype of this bacterium developed pre-cancerous intestinal growths and accelerated tumor formation compared to normal mice.
Researchers studying these bacteria and some of their species E.coli Also associated with colorectal cancer, researchers believe that a diet rich in ultra-processed foods may alter the composition of the gut microbiome in ways that enable these strains to thrive and increase the risk of cancer progression through a number of mechanisms.
“Some bacteria cause intestinal cells to acquire stem cell-like properties, increasing the likelihood of cancer formation at the cellular level,” says Dr Meera Patel, a researcher at the Colorectal and Peritoneal Oncology Laboratory at the University of Manchester.
“There is also a theory that some bacteria can disrupt the intestinal vascular barrier, which stops bacteria from spreading from your colon into your wider circulation, and if your intestinal vascular barrier is disrupted, then tumor cells can move out of the colon and metastasize to other organs.”
excessive alcohol
However, there are other cases of cancer in young people where microbial involvement has not yet been identified.
Testicular cancer, for example, is the most common solid tumor cancer diagnosed in young men, and according to the NHS, the number of cases identified each year in the UK has doubled since the 1970s, for reasons cancer experts are still trying to unravel. to understand.
Family history is one of the biggest risk factors for this type of cancer, but some community studies have also found a link between excessive alcohol consumption and a type of the disease called testicular germ cell carcinoma.
Young men who consume 14 or more alcoholic beverages per week have been found to be at greater risk, along with a diet high in fat, red meat and dairy products and low in fruits and vegetables.
new treatments
However, the emerging link between microbes and different forms of early-onset cancers in young people could lead to new targeted treatments such as phage therapy, which involves administering to the patient specially designed viruses programmed to feed on specific types of problematic bacteria. or targeted vaccines.
“You can vaccinate mice before they infect them.” F. nucleatum Beggs said he will look into whether this makes a difference in terms of outcomes in terms of polyps and cancers. “If that’s the case, there would be a strong argument for doing a phase one trial in humans to see if it would reduce the incidence of colorectal cancer.”
O’Brien predicts that in the coming years, the specific microbial composition of the tumor may be used to inform treatment decisions.
“We don’t currently use this information, but I think we might be able to obtain it in the future and use it to decide whether this is a particularly aggressive tumor and whether the patient needs higher doses of chemotherapy.” says.
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