A recently published study has suggested that there is an increased thyroid cancer risk associated with glucagon-like peptide-1 (GLP-1) receptor agonists, but what does this study mean for primary care when prescribing this medication to our patients?
The evidence review relating to the use of GLP-1 receptor agonists has revealed a 50% increase in thyroid cancer incidence associated with their use.
To put this in context, thyroid cancer is relatively rare and represents the 20th most common cancer in the UK. In a population of over 67 million, there are about 3900 new thyroid cancer diagnoses per year. However, with consideration of female cancers, thyroid cancer is the 17th most common type, with about 2800 cases per year. Thyroid cancer is more common, then, in women than men.
So, how are we to interpret this new evidence? Well, there are GLP-1 receptors on the thyroid gland, and so overstimulation of these receptors seems a possible mechanism for development of this cancer. In the US, the medication regulators (the Food and Drug Administration) contraindicated semaglutide if there is a personal or family history of medullary thyroid cancer or if a person has multiple endocrine neoplasia type 2 (which is associated with an increased risk of various cancers).
I suppose that because thyroid cancer is rare, then the encountering by GPs or others of GLP-1-associated thyroid cancer will be rare. And if something is rare, then even with an increased risk it will still be rare.
But we as clinicians need to be aware of these data and to appropriately inform and counsel our patients.
To find out more about the evidence relating to GLP-1 receptor agonists and thyroid cancer risk, see this page on GPnotebook.
Other highlights in this month’s email include updated advice and evidence relating to the Shingles vaccine, new evidence on the use of benzodiazepines in pregnancy and a summary of the association between aripiprazole and pathological gambling.