Incretin-based therapies show no significant thyroid cancer risk increase in meta-analysis of 84,237 patients.
Background
The safety profile of incretin-based therapies, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RAs, has been a subject of debate, particularly concerning their potential association with thyroid cancer risk. Observational studies have yielded conflicting results, creating uncertainty for clinicians and patients. This systematic review and meta-analysis specifically addresses this gap by synthesizing evidence exclusively from randomized controlled trials (RCTs), aiming to provide a more robust assessment of this controversial safety concern.
Study Design
Researchers conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the association between incretin-based therapies and thyroid cancer risk. They searched PubMed, EMBASE, and ClinicalTrials.gov for RCTs of approved incretin-based therapies with at least 26 weeks of follow-up that reported thyroid cancer events. Data from 15 RCTs enrolling a total of 84,237 participants were extracted and analyzed. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool, and pooled odds ratios (ORs) with 95% CIs were calculated using a random-effects model. Certainty of evidence was evaluated via the GRADE framework.
Results
The meta-analysis, encompassing 15 RCTs and 84,237 participants, found no statistically significant association between incretin-based therapy use and thyroid cancer risk. Across all included trials, 28 thyroid cancer events were reported in the incretin-based therapy groups, compared to 15 events in the control groups. The pooled odds ratio was 1.52 (95% CI 0.86-2.68), with an I2 value of 0.0%, indicating no heterogeneity across studies. These findings remained consistent across various prespecified subgroup and sensitivity analyses. However, the certainty of evidence was rated as very low due to serious imprecision, primarily attributed to the rare occurrence of thyroid cancer events within the study populations. This imprecision means that while no significant increase was detected, a clinically relevant increase cannot be definitively ruled out.
The meta-analysis of 84,237 participants showed no statistically significant increase in thyroid cancer risk with incretin-based therapies (OR 1.52, 95% CI 0.86-2.68).
Key Findings
- Meta-analysis included 15 RCTs with 84,237 participants evaluating incretin-based therapies.
- No statistically significant association found between incretin-based therapy and thyroid cancer risk.
- Pooled odds ratio was 1.52 (95% CI 0.86-2.68), with 0.0% heterogeneity (
I2). - 28 thyroid cancer events occurred in incretin groups vs. 15 in control groups.
- Certainty of evidence rated very low due to serious imprecision from rare events.
Why It Matters
This meta-analysis provides crucial reassurance for clinicians and patients regarding the short-to-medium term safety of incretin-based therapies concerning thyroid cancer risk. For individuals using or considering GLP-1 RAs or dual GIP/GLP-1 RAs, these findings suggest that the immediate risk of thyroid cancer is not significantly elevated based on current RCT data. While the evidence does not demonstrate a statistically significant increase, the 'very low' certainty due to rare events and limited follow-up means that long-term surveillance remains prudent. This implies that while current protocols are likely safe, ongoing monitoring for new signals, especially with prolonged use, is still warranted, reinforcing the need for continued pharmacovigilance rather than immediate changes to prescribing guidelines.
incretin-based-therapies
glp-1-agonist
gip-agonist
thyroid-cancer
safety
meta-analysis