We know that obesity is a risk factor for cancer but we don’t really understand why. Since that link exists, we hypothesised that these drugs, GLP1 agonists, could potentially be beneficial for cancer prevention. These drugs bind to different targets and they impact different pathways and some of those pathways are associated with weight loss but other pathways are associated with inflammation. We know that inflammation is a hallmark of cancer and is something that tumours need for growth and for development. So that was the background behind our hypothesis that there could be an association between cancer incidence and use of these drugs.
Could you outline the methodology?
We looked at a population of women who would be eligible for screening mammography between the ages of 45 and 80 and we were able to link the medications with women undergoing breast imaging at the University of Pennsylvania. So we knew who had taken GLP drugs and who had not. We were able to see in a cohort of over 100,000 women who were overweight that the women who took the GLP-1 agonists had a 30% reduced incidence of breast cancer compared to women who didn’t take the drugs.
We wanted to make sure the populations were equivalent in various things that could be a risk factor for breast cancer like age, race, ethnicity, history of diabetes, and even breast density because breast density alone is a risk factor for breast cancer. So we were able to match a cohort so that they had similar baseline characteristics and this is where we found that 30% decrease.
What did you find?
The findings of our study are that women between the ages of 45 and 80 who were presenting for breast imaging at the University of Pennsylvania, in that group of women the women who were taking the GLP-1 agonists had a 30% reduced incidence of breast cancer. So this is an association in an observational study.
What were the limitations of the study?
The limitations of the study are that it is observational. This is an association but it doesn’t yet prove causality. Causality is shown in a clinical trial. So we have spent the last year, along with the Eastern Cooperative Oncology Group, the American College of Radiology and the TMIST clinical trial group, that’s the mammographic screening trial that’s currently ongoing, to design and develop a clinical trial to test whether these drugs are causal in reducing the incidence of breast cancer.
So even though GLP-1 agonists have been shown to impact multiple different cancer types – lung, colon, breast, liver and even leukaemia – the ideal format for the clinical trials to look at breast cancer incidence, because breast is such a common cancer impacting one in eight women, so you can have enough events to power the clinical trail with the least amount of people.
What’s next?
The next thing for us is to secure funding for the clinical trial and we’ve been talking to government, we've been talking to industry, we’ve been talking to multiple groups to try to establish a consortium to fund this very important clinical trial. It’s important for the health of women and potentially for the health of all Americans, potentially for the health of everybody, that we actually establish causality and that we don’t assume that these drugs are going to have cancer prevention effects but that we show it through level 1 evidence.
