Ozempic and risk of thyroid and pancreatic cancer? Reproduced from an article on Medscape March 2023
Ozempic works by affecting expression of GLP1 – a pancreatic hormone that boosts the effects of insulin, slows gastric emptying, and affects some of the appetite increasing chemicals in the brain. The weight loss effects of Ozempic are impressive, so long as people keep injecting.
A few years ago, alongside American (FDA) approval of GLP-1 agonists, a warning accompanied the products’ labels to not use this class of medications in patients with medullary thyroid cancer, a family history of medullary thyroid cancer, or multiple endocrine neoplasia syndrome type 2. This warning was based on data from animal studies.
Human pancreatic cells aren’t the only cells that express GLP-1 receptors. These receptors are also expressed by parafollicular cells (C cells) of the thyroid, which secrete calcitonin and are the cells involved in medullary thyroid cancer. A dose-related and duration-dependent increase in thyroid C-cell tumour incidence was noted in rodents. But not in monkeys.
Over a decade ago, a study examining the FDA’s database of reported adverse events found an increased risk for thyroid cancer in patients treated with exenatide, another GLP-1 agonist but subsequent studies did not confirm this relationship.
A LEADER TRIAL in the USA investigated the effects of liraglutide in patients with type 2 diabetes and showed no effect of GLP-1 receptor activation on human serum calcitonin levels, C-cell proliferation, or C-cell malignancy. F
Differing from prior studies, a recent nationwide French healthcare system study provided newer data suggesting a moderate increased risk for thyroid cancer in a cohort of patients with type 2 diabetes who were taking GLP-1 agonists. The increase in relative risk was noted for all types of thyroid cancer in patients using GLP-1 receptor agonists for 1-3 years.
The drug companies have offered a perspective on the limitations of these findings, we must note that declarations of interest offer may bias any findings against these drugs. You may wish to look up the work of Caroline Thompson and Til Sturmer if you want to learn more.
So, without going into detail about risk, and type of tumour that have attracted warnings, the jury is still out. For example this is one question that has attracted controversy.
Is a detection bias present where weight loss makes nodules more visible on the neck among those treated with GLP-1 agonists? And/or are patients treated with GLP-1 agonists being screened more stringently for thyroid nodules and/or cancer?
Advice to Patients taking Ozempic
The TikTok videos may continue, the celebrity chatter may increase, and doctors must continue to make their own judgement about decision-making and guidance for our patients.
There may be risks both of thyroid and pancreatic cancer but we don’t yet know for whom and why and dose dependency.
It’s prudent to advise patients that if they have a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia syndrome type 2, in particular, they should avoid using Ozempic and any similar medication. Thyroid cancer remains a rare outcome, and GLP-1 receptor agonists remain a very important and beneficial treatment option for the right patient.