People who go on to develop precancerous colon polyps have significant variations in the type and diversity of bacteria in their gut microbiome compared with healthy people, according to new research presented at UEG Week 2023, the annual conference of United European Gastroenterology.
These changes can be detected before the polyps become colorectal cancer, says lead author Ranko Gacesa, PhD, researcher and professor at University Medical Center in Groningen, Netherlands. “If these findings are confirmed, this means that looking at the gut microbiota could improve on current noninvasive fecal tests used to detect and prevent colorectal polyps and cancer,” he says.
How Does This Study Build on Earlier Research?
Prior research has found that certain strains of bacteria and the compounds those bacteria make inside the gut are associated with higher or lower risks of colorectal cancer, according to the American Institute for Cancer Research. But which comes first — that is, whether microbiome changes alter the course of the cancer or if the cancer results in microbiome changes — isn’t completely understood.
Lower Gut Diversity Linked With Precancerous Polyps
To investigate the connection between different bacteria found in the gut and precancerous colon polyps, researchers linked data from over 8,000 participants from the Dutch Microbiome Project with the Dutch nationwide pathology database to identify all recorded cases of colonic biopsies from the last 50 years.
Researchers analyzed the gut microbiomes of people who developed precancerous colorectal lesions before fecal sampling between 2000 and 2015 (214 people), as well as those who developed lesions after fecal sampling between 2015 and 2022 (305 people). Then they compared those gut microbiome findings with the microbiomes of people with normal colonoscopy findings (202 people) and the general population.
Investigators found that individuals with precancerous lesions had reduced gut bacteria diversity compared with healthy individuals.
It’s Still Unclear Why Certain People Have ‘Bad’ Microbes in the Gut
These findings make sense given that, in general, higher microbiome diversity is generally considered to be an indicator of “good” gut health and lower diversity as less desirable, says Dr. Gacesca. “This is based on studies which identified that patients with certain diseases such as inflammatory bowel disease [IBD] have reduced microbiome diversity in the gut,” he says.
Colorectal Polyps Typically Take 5 to 10 Years to Develop
The large number of subjects in the study and the lengthy follow up — researchers were able to follow participants for decades — are both important strengths of this study, says Suneel Kamath, MD, a hematologist and medical oncologist and assistant professor of medicine at Cleveland Clinic in Ohio, who was not involved in the research.
“Following participants for a relatively long period is especially important with colorectal cancer studies because it’s often a 5- to 10-year process to go from a normal colon to a polyp forming, and then forming cancer, and so you really need a pretty substantial period of follow up,” he says.
Bacterial Species Associated With Potential Risk of Colorectal Cancer
“It is known from previous studies that some of the species we identified are linked to the development of colorectal lesions that are potentially genotoxic,” says Gacesca, meaning they cause mutations in cells which may lead to cancer. “For example, Bacteroides fragilis is known to produce toxin which can contribute to chronic low-grade inflammation, and chronic gut inflammation is likely to be genotoxic/carcinogenic,” he adds.
“Another example is Akkermensia species which can degrade gut mucus and thus reduce the capability of the organism to defend against pathogens, again leading to chronic inflammation and potentially cancer,” he says.
Additionally, the analysis found that the bacterial species from the family Lachnospiracea and the genera Roseburia and Eubacterium were linked with the future development of lesions.
But researchers still don’t know why certain people have these “bad” microbes in their guts, says Gacesca. “And there is no clear consensus on the effectiveness of microbiome-altering therapies,” he adds.
Could Probiotics and Prebiotics Help Prevent Colorectal Cancer?
If confirmed, these findings could be used to help point the way to microbiome-targeted therapies, such as fecal microbiome transplants and probiotics and prebiotics. “This would require extensive testing to demonstrate that such probiotics have expected effect,” says Gacesca.
The work of creating these therapies is ongoing, and it is likely we will see advances in the near to mid-term future.
“What’s challenging in the field right now is that which bacteria end up being significant — or not significant — can really vary a lot across different studies. One in particular, Fusobacterium nucleatum, which is a bacterium that exists in the mouth, has been associated with increased risk of a lot of different cancers, including colorectal cancer. I was a little surprised to see that it wasn’t called out specifically in this study,” says Dr. Kamath.
The finding that Roseburia was associated with the development of precancerous polyps was also surprising, says Kamath. “It’s been linked to helping with blood sugar control and weight loss and so it’s often associated with positive factors,” he says.
These conflicting findings highlight the relative newness of so much research on the microbiome and its role in cancer. It is a burgeoning field, says Kamath. “We need a lot more studies to really prove what’s truly going on here,” he adds.
Colorectal Cancer the Third Most Common Cancer
Not including skin cancers, colorectal cancer is the third most common cancer in both men and women in the United States, according to the American Cancer Society. It’s estimated that there will be more than 150,000 new cases of colon and rectal cancers in the United States this year.
It’s recommended that people who are at average risk start regular screening at age 45, either with a stool-based test or a visual exam such as a colonoscopy or virtual colonoscopy.
Risk factors for colorectal cancer include age, heath history, and genetic vulnerabilities, as well as lifestyle-related factors including having overweight or obesity, lack of physical activity, a diet high in processed meats and red meat, smoking, and heavy alcohol use, per the society.
Should You Seek Out Probiotics to Prevent Colorectal Cancer?
Right now, there isn’t enough solid evidence to recommend certain probiotics to reduce the risk of colorectal cancer, says Kamath.
He suggests focusing on known risk factors such as achieving and maintaining a healthy weight. “In the United States, the lack of microbial diversity and poor gut health is driven by overweight and obesity. As we continue to get more data on colorectal cancer concern, that’s increasingly the most concerning risk factor,” he says.
He recommends the Mediterranean diet to his patients who want to reduce their risk. “I’m a big fan of that way of eating, focusing on lean meats, fatty fish, beans, legumes, nuts, fresh fruit, and leafy green vegetables, and limiting processed foods,” he says.
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
