Physicians in the United States are beginning to prescribe weight-loss medications like Mounjaro and Wegovy to cancer patients in an effort to prevent the disease from recurring. This approach, observed at the Memorial Sloan Kettering Cancer Centre in New York, is based on emerging evidence suggesting that the weight loss induced by these drugs may reduce the risk of obesity-related cancers returning.
Experts indicate that prescribing these glucagon-like peptide-1 (GLP-1) receptor agonists is an increasingly common practice across the U.S. Obesity is currently linked to 13 types of cancer, including breast, colon, stomach, and prostate cancers.
Dr. Marisa Weiss, founder of the U.S.-based support group breastcancer.org, commented on the challenges of lifestyle changes for cancer patients. "People say that they want to reduce their cancer risk, but human nature means that making lifestyle changes is really hard," she said. "Now we have the GLP-1s we have what many people think is a magic bullet to help fix this overwhelming tendency to put on weight as you go through life, and especially after a breast cancer diagnosis." Weiss anticipates that in the future, GLP-1s might be viewed similarly to statins or blood-pressure medications for women undergoing breast cancer treatment.
Around eight out of ten breast cancer cases in the UK are estrogen-receptive, meaning the tumors are fueled by a hormone produced in fat cells. Dr. Sherry Shen, an oncologist at Memorial Sloan Kettering, noted that studies show weight loss after a breast cancer diagnosis is associated with better outcomes. "It's logical GLP-1s could help with that," Shen stated. Additionally, these injections are thought to reduce inflammation, another cancer risk factor, and some patients report fewer side effects from their cancer treatments, including chemotherapy.
However, the National Health Service (NHS) in the UK is currently unable to prescribe GLP-1s to cancer patients, as they are only licensed for individuals with obesity and a weight-related condition such as high blood pressure or type 2 diabetes. There is also caution regarding patients obtaining these drugs privately, due to concerns they could interfere with the absorption of certain medications designed to prevent tumor recurrence.
Dr. Caroline Wilson, an oncologist at The Christie NHS Foundation Trust in Manchester, explained that GLP-1s slow the digestive process. "There's evidence already that some drugs, such as contraceptive pills, are not absorbed as well in people who take them," Wilson said.
Leila Gonzalez, a 53-year-old from New Jersey, shared her experience after being diagnosed with six tumors in her right breast two years ago. At the time of her diagnosis, she was clinically obese, weighing 13 stone 9 pounds (approximately 191 pounds). Alongside two cancer medications, Gonzalez began taking Mounjaro under medical supervision and has since lost over four stone (approximately 56 pounds).
Gonzalez, who experienced fatigue during her treatment, found that the medication aided her weight loss when she lacked the energy for exercise. "It’s hard enough to find the motivation to lose weight and exercise if you’re living a regular life, so to do it going through cancer treatment and grief – I lost my mother while having radiotherapy – is almost impossible," she stated. Gonzalez added, "I don’t care if I have to stay on it my whole life. The more I can keep the weight off, the less likely it is my cancer will come back."
Several studies suggest that the weight loss achieved with drugs like Wegovy and Mounjaro may decrease the likelihood of cancer recurrence. Reports from a cancer support group indicate that some individuals have experienced significant weight loss and have the support of their oncologists for using these medications. One participant noted, "If I want to lessen my chances of cancer returning in the future I am trying to lose fat stores."
Furthermore, observational reports presented recently suggested that weight-loss drugs could potentially reduce the risk of developing cancer in the first place by up to 30 percent. 
