Obesity has been linked to a number of health problems, including type 2 diabetes, hypertension, heart disease, liver problems, and joint disease. But many people may not know that the condition is also closely linked to cancer.
In a study published in JAMAresearchers provide the strongest evidence to date supporting the link between obesity and cancer, and the benefits of weight-loss surgery in lowering the risk of developing or dying from cancer.
The study involved more than 30,000 obese patients: some underwent bariatric surgery to lose weight, and some served as non-surgical controls and received standard care for their obesity, including information about diet and exercise. The results showed that 10 years after surgery, people had a 32% lower risk of developing 15 common cancers and a 48% lower risk of dying from cancer, compared with those who had not had the weight-loss surgery.
“What we’ve observed here is a very large effect,” says Dr. Steven Nissen, a cardiologist at Cleveland Clinic and the senior author of the article. “I think these data are as strong as they will be available for quite some time to support yet another reason why weight loss is a really important public health intervention.”
dr. Ali Aminian, director of the Cleveland Clinic’s Bariatric and Metabolic Institute and the study’s lead author, says obese people should reduce their risk of developing or dying from cancer if they need to lose a significant amount of weight — more than Most people can lose weight sustainably with diet and exercise alone. The people in the study received one of two types of bariatric surgery between 2004 and 2017: 66% in the surgery group received a gastric bypass, in which the surgeon divides the stomach into two smaller pouches and diverts part of the bowel into both sections, and 34 % underwent gastric sleeve surgery, a procedure in which the surgeon removes 80% of the stomach, leaving a strip the size of a banana. (Aminian says gastric sleeve procedures have since become more common in the U.S., accounting for 65% to 70% of bariatric surgeries.) These procedures can help people lose 20% to 25% of their body weight, which the researchers say is the threshold for seeing benefits when it comes to cancer risk. (Although Aminian and several of the other authors of the study have received grants from Medtronic, which makes devices for bariatric surgery, the company was not involved in the JAMA study.)
“I want more GPs to have serious conversations with their patients about the consequences of obesity and the reversibility of the morbidity and mortality associated with obesity,” says Nissen. “The primary care physician can begin the conversation with their patients to consider surgery and determine if they qualify.”
Obesity can affect cancer risk in several ways. Studies have shown that fat cells are not inert, but very metabolically active. They make substances that contribute to inflammation in the liver, which creates “a toxic environment that can increase the risk of cancer,” Aminian says. Obesity can also contribute to elevations in hormones such as estrogen, which have been linked to a higher risk of breast and uterine cancer in women. In fact, the study found that endometrial cancer was one of the diseases most closely linked to obesity, and that bariatric surgery reduced the risk of endometrial cancer by 53% — more than any other type of cancer analyzed in the study.
While the study found that surgery, and the dramatic weight loss that came with it, was associated with a significant reduction in cancer, both Nissen and Aminian acknowledge that nearly 42% of people in the U.S. now classified as obese have undergone surgery. is not a practical solution. option for all. Not everyone is a candidate for the invasive surgery, which carries significant risks as it involves major diversion of the digestive tract. Diet and exercise alone generally do not result in weight loss as significant as the type seen in the study, primarily because it is challenging for people to adhere to the strict regimens required for sustained weight loss.
Several weight-loss drugs have recently been approved by the US Food and Drug Administration that can lead to adequate weight loss, similar to that of surgery, but they are not yet widely used as a tool to fight obesity. Nissen is currently leading a study of 15,000 patients sponsored by Eli Lilly who makes one of the drugs, tirzepatide, which has been approved to treat obesity in people with type 2 diabetes and has helped them lose up to 25% of their body weight. . The results of that study may give primary care physicians more confidence to help their patients optimize weight loss strategies and help prevent health risks, including cancer.
“One tool is in the hands of surgeons, and now there are tools in the hands of non-surgeons [in the form of drug treatments,]Nissen says. “Between these two strategies, I actually think there may be light at the end of the tunnel.”
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