SUMMARY: Colorectal cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 158,850 new cases of CRC will be diagnosed in the United States in 2026 and about 55,230 patients will die of the disease. Colorectal cancer is a heterogeneous disease classified by its genetics, and even though the diagnosis of CRC in the US is dropping among people 65 years and older, the incidence has been rising in the younger age groups, with 12% of CRC cases diagnosed in people under age 50.
Background: Rethinking Chemoprevention in CRC
Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide, underscoring the need for effective prevention strategies. Historically, low-dose Aspirin has been investigated for its potential chemopreventive effects, largely due to its anti-inflammatory properties. However, its clinical utility has been tempered by modest benefit and clinically significant risks, particularly gastrointestinal bleeding and ulceration. As a result, Aspirin is no longer broadly recommended for CRC prevention in average-risk populations.
In parallel, Glucagon-Like Peptide-1 Receptor Agonists (GLP-1RAs), now widely prescribed for type 2 diabetes and obesity, have emerged as potential anticancer agents. Preclinical evidence suggests these drugs may inhibit colorectal carcinogenesis through anti-inflammatory and anti-proliferative effects, including downregulation of the PI3K/Akt/mTOR signaling pathway. Despite this mechanistic rationale, real-world comparative data have been lacking, until now.
Study Design and Methods
A large-scale retrospective analysis leveraging the TriNetX network, encompassing data from approximately 150 million patients across 106 healthcare organizations, offers new insight into this evolving landscape. In this study, 281,656 patients were propensity score-matched to compare GLP-1RA users with Aspirin users (140,828 per cohort), balancing demographics, comorbidities, and key confounders. The cohorts were broadly similar, with a mean age of 58 years and a predominance of female participants (69%). The Primary endpoint was CRC incidence.
Key Findings
GLP-1 receptor agonists were associated with a meaningful reduction in colorectal cancer incidence compared with Aspirin.
Over a median follow-up of approximately 5.9 years for GLP-1RA users and 4.8 years for Aspirin users, GLP-1RA therapy was associated with a statistically significant reduction in CRC incidence. Specifically, CRC occurred in 0.13% of GLP-1RA users compared with 0.176% of Aspirin users, translating to a 26% relative risk reduction. These findings were consistent across sensitivity analyses at 12 and 36 months, as well as across multiple subgroups, including variations in age, BMI, and glycemic status.
Notably, the observed benefit extended to younger populations and individuals without obesity or diabetes, suggesting potential effects beyond metabolic modulation. Among individual agents, Semaglutide demonstrated a statistically significant association with reduced CRC risk, while Liraglutide and Dulaglutide also showed signals of benefit in secondary analyses.
In contrast, no significant risk reduction was observed among patients with tobacco use or established atherosclerotic disease. Tirzapeptide and Exenetide did not show the same significance in this study and these findings raise important questions regarding potential heterogeneity within the class.
Safety Profile
The safety comparison revealed distinct differences between the two cohorts. From a safety perspective, GLP-1RA use was associated with fewer serious adverse events such as gastrointestinal bleeding, stomach ulcers, and acute kidney injury compared with Aspirin. As expected, gastrointestinal symptoms, including nausea, vomiting, abdominal pain, and diarrhea, were more frequently reported with GLP-1RAs, though these were generally manageable.
Clinical Interpretation
Despite the relative risk reduction, the absolute benefit at the individual level remains modest, with a number needed to treat (NNT) of approximately 2,198 to prevent one case of CRC. However, this must be interpreted within a broader population context. With millions of individuals currently prescribed GLP-1RAs for metabolic indications, even small individual risk reductions could translate into meaningful public health impact.
This study represents the first large, real-world, head-to-head comparison of GLP-1 receptor agonists and Aspirin for primary CRC prevention. The findings underscore a potential paradigm shift, positioning GLP-1RAs as agents that may extend beyond metabolic disease management into the realm of cancer prevention.
While these results are compelling, they remain hypothesis-generating. Prospective randomized clinical trials will be essential to validate causality, clarify agent-specific effects, and define optimal patient populations. Nonetheless, the convergence of metabolic and oncologic benefits highlights an emerging opportunity to rethink prevention strategies in colorectal cancer.
Key Takeaways for Oncology Practice
- GLP-1 receptor agonists were associated with a 26% relative reduction in CRC incidence compared with Aspirin
- Benefits were consistent across multiple patient subgroups and timepoints
- Semaglutide emerged as the most robust individual agent in this analysis
- GLP-1RAs demonstrated a more favorable safety profile, particularly regarding bleeding risk
- Absolute risk reduction is small, but population-level implications may be significant
GLP-1 receptor agonist vs aspirin for primary prevention of colorectal cancer: Evidence from a real-world head-to-head comparison. Jones C, Obomanu E, Neely A, et al. J Clin Oncol 44(suppl 2; abstr 18), 2026.
