The slimming drug revolution that could also prevent cancer

The new generation of anti-obesity drugs could also become a weapon in cancer prevention. To test this, an international group of experts proposes to launch a large, long-term clinical trial that would test the effectiveness of molecules such as semaglutide and tirzepatide in reducing the risk of cancers associated with excess weight. The proposal will be presented at the European Congress on Obesity (Echo 2026), scheduled for 12-15 May in Istanbul. The idea is to follow around 5,000 overweight or obese people at high risk of cancer for at least ten years, to see whether the drugs that are now revolutionising the treatment of obesity can also prevent the onset of cancer.

The Padriac project, funded by Cancer Research Uk, is led by Matthew Harris with a team from the Universities of Manchester and Leeds, with the collaboration of Andrew Renehan from the University of Manchester's Division of Cancer Sciences. The team believes that the evidence in support of the new generation of obesity drugs (which include Glp-1 agonists and also Glp-1/Gip dual agonists) is so strong that a clinical trial of these drugs in the prevention of obesity-related cancers is necessary.

Obesity is now considered a major global health challenge. According to international estimates, more than 650 million adults live with obesity and the number could exceed one billion by 2030. Excess weight not only increases the risk of diabetes or cardiovascular disease, but is also associated with 13 different types of cancer, including colorectal cancer, breast cancer after menopause, endometrial cancer, oesophagus cancer and kidney cancer. The biological causes are not fully elucidated, but scientists point to several mechanisms: chronic inflammation, hormonal changes, insulin resistance and changes in the immune system. Parallel to the growth in obesity, an increase in cancers related to excess weight has also been observed in recent years, a trend that epidemiological models suggest will continue in the coming decades.

In recent years, the pharmacotherapy of obesity has experienced a breakthrough thanks to Glp-1 receptor agonists and new multi-incretin drugs. These molecules, initially developed for type 2 diabetes, have demonstrated a strong ability to induce weight loss. The most recent clinical studies indicate that these therapies can lead to a reduction in body weight of between 12% and 18%, results that are far superior to interventions based on diet and exercise alone. In addition to weight loss, the drugs have also shown benefits on several obesity-related diseases, including type 2 diabetes, cardiovascular disease and kidney problems. This is why many researchers believe it is plausible that they may also influence the risk of obesity-related cancers.

The hypothesised trial would involve two groups of participants: a group receiving a Glp-1 agonist drug (or similar molecules) together with a behavioural programme of losing; a control group following only the diet- and lifestyle-based behavioural intervention. Participants would be people with a body mass index between 27 and 35 and with conditions considered precursors to cancer, such as Barrett's oesophagus, colon polyps, endometrial hyperplasia or metabolic steatohepatitis with fibrosis. According to the researchers, focusing on a high-risk population would reduce the size of the study. If the entire obese population were involved, about 50,000 participants would be needed, making the trial too expensive.