Dr. Daniel Drucker, an endocrinologist and senior scientist at Mount Sinai Hospital in Toronto, is shown in a handout photo. Researchers are probing a link between bariatric surgery and higher colon cancer risk. THE CANADIAN PRESS/ HO-Mount Sinai Hospital -
Dr. Daniel Drucker, an endocrinologist and senior scientist at Mount Sinai Hospital in Toronto, is shown in a handout photo.
Researchers are probing a link between bariatric surgery and higher colon cancer risk.
THE CANADIAN PRESS/ HO-Mount Sinai Hospital
And that appears to stimulate overproduction of a gut hormone that may spur the growth of polyps in the colon that have a propensity to become malignant, suggests Dr. Daniel Drucker, an endocrinologist at Mount Sinai Hospital in Toronto.
In studies in laboratory mice, a research team led by Drucker
found the digestive hormone GLP-1 was "a pretty potent growth factor" for the intestine in the animals, as well as a catalyst for intestinal tumours in other lab mice specially bred to study colorectal cancer.
"If we gave the mice more GLP-1, they got more tumours," said Drucker, a senior scientist at the hospital's Lunenfeld-Tanenbaum Research Institute.
is quick to point out that mice aren't humans, he
said the animal studies go a long way in providing a biological explanation.
"So if you say under what conditions might a human find themselves with increased levels of GLP-1 and the risk for intestinal tumour formation, probably the best delineated situation is the condition of bariatric surgery," he
said, explaining that patients have elevated levels of GLP-1, other digestive hormones and bile acids, which are all known to stimulate intestinal growth.
Calling bariatric surgery the best available treatment for obesity and Type 2 diabetes, Drucker
said eligible patients shouldn't shy away from the operation but should ensure they have regular screening for colon cancer afterward.
"We're very conservative.
We don't make clinical recommendations based on findings in mice," he
"But we would say that given the already available data that patients with bariatric surgery might have an increased risk of colon cancer and our new findings providing an explanation for why that might happen - have your colonoscopies."
That's also the advice for those taking a class of drugs used for diabetes control that work by activating the GLP-1 receptor to increase insulin and decrease blood glucose.
"It's important to state that GLP-1 doesn't by itself ... cause intestinal tumours," said Drucker
"But what we believe is that if you already have a propensity to form a tumour - so if you had an intestinal polyp, which is very common - then we believe that the growth of that polyp would be increased if the levels of GLP-1 were elevated."
While the research, published Tuesday in the journal Cell Metabolism, needs to be replicated by other researchers and confirmed in humans, he said patients should discuss the potential link between increased GLP-1 and colon cancer with their doctors.