Weight-loss pens: GLP-1 receptor agonists linked to lower colorectal cancer risk in inflammatory bowel disease

Weight-loss pens - medicines widely prescribed for obesity and type 2 diabetes - may come with an extra potential advantage that has drawn scientific attention. New research has reported an association between use of so-called GLP-1 receptor agonists and a lower risk of colorectal cancer in people living with inflammatory bowel disease.

The findings were presented at the American Society of Clinical Oncology (ASCO) annual meeting, one of the leading global events in oncology, and focused on patients considered more vulnerable to developing this type of tumour.

Higher-risk population

The study centred on individuals diagnosed with inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis. These conditions drive long-term inflammation in the digestive tract, which over time can increase the likelihood of cellular changes and, in turn, colorectal cancer.

To explore a possible link between these medicines and cancer risk, the researchers analysed records from the TriNetX platform, which aggregates health data from more than 150 million patients.

Within the database, the team identified more than 1.1 million people with inflammatory bowel disease; around 70,000 of them were using medicines in the GLP-1 receptor agonist class.

Marked reduction in cancer cases

After matching patients with similar characteristics, the researchers found meaningful differences between the groups.

Across five years of follow-up, colorectal cancer incidence was 0.20% among those using the medicines, compared with 0.43% among those who were not taking this therapeutic class. According to the authors, this equates to an approximately 51% reduction in the likelihood of developing the tumour.

A similar pattern was seen among patients who had both inflammatory bowel disease and type 2 diabetes. In that subgroup, colorectal cancer incidence was 0.31% for GLP-1 receptor agonist users versus 0.57% for non-users - the equivalent of a 46% lower risk of diagnosis.

What might explain the result?

Although the study was not designed to determine why this association appears, the researchers propose several possible explanations.

One suggestion is that the medicines could help indirectly through weight loss, improved glucose control, and reduced inflammatory processes in the body. These factors are commonly linked with better metabolic health and may influence the development of chronic diseases.

Even so, it remains uncertain which mechanism might be involved, and whether the observed benefit is a direct effect of the medicines themselves.

A promising finding, but still preliminary

Despite the interest generated by the results, the authors emphasise that this is an observational study. That means it can identify a statistical association, but it cannot prove cause and effect.

Put differently, the data indicate that people taking GLP-1 receptor agonists had fewer cases of colorectal cancer, but they do not allow the conclusion that the medicines caused the reduction.

For that reason, specialists highlight the need for further research to confirm the findings and to clarify the underlying mechanisms.

Until more robust evidence is available, weight-loss pens remain indicated only for approved conditions such as obesity and type 2 diabetes, and should be used under medical supervision.