TOPLINE:

Among 569,850 adults with cancer, 4.1% received GLP-1 receptor agonist (GLP-1 RA) prescriptions for obesity, with the highest rates in thyroid (10.1%), breast (7.2%), and endometrial (7.1%) cancers. Prescribing patterns showed a steady increase, mirroring general population trends, while varying substantially by cancer type.

METHODOLOGY:

• Known side effects of chemotherapy, including cachexia and toxicity, raise questions about prescribing GLP-1 RAs to patients with cancer. Plus, limited evidence exists regarding the benefit-risk profile of these medications in patients with cancer.
• Researchers analyzed data from the Epic Cosmos dataset, an electronic health records repository, following the STROBE reporting guideline.
• Analysis included 569,850 adults newly diagnosed with 14 common cancers between January 2021 and May 2025, with BMI ≥ 30 and at least one obesity-related comorbidity.
• Monthly incident and prevalent prescription rates of semaglutide and tirzepatide were calculated, excluding oral formulations and prescriptions outside active cancer diagnosis periods.
• Statistical analysis employed unpaired two-tailed t-tests for continuous variables and chi-squared tests for categorical variables, with Bonferroni correction for multiple comparisons across cancer types.

TAKEAWAY:

• Patients prescribed GLP-1 RAs were younger (mean difference, 8.4 years; mean age, 58.7 vs 67.1 years; P < .001), more often female (70.6% vs 52.1%; P < .001), and had higher mean BMI (mean difference, 4.5; 37.8 vs 33.3; P < .001) compared with those without prescriptions.
• Incident prescription rates showed an increasing trend from 0.01% to 0.9% (P < .001), with prevalent prescription rates reaching 5.1% for all cancer types by May 2025.
• The highest prevalent prescription rates were observed in thyroid (10.1%), breast (7.2%), and endometrial (7.1%) cancers, while the lowest rates were seen in lung (2.8%), liver (2.4%), and pancreatic (1.3%) cancers.
• According to the authors, early and heterogeneous adoption of GLP-1 RAs was noted in oncologic settings, with particularly high prescribing rates among patients with obesity-related cancers.

IN PRACTICE:

“Given the rapid and heterogeneous adoption of GLP-1 RAs in populations with preexisting cancer but without diabetes — and absence of cancer-specific prescribing guidelines — there is an urgent need for evidence-based recommendations to optimize safety and outcomes,” wrote the authors of the study.

SOURCE:

This study was led by Chungsoo Kim, PharmD, PhD, Center for Outcomes Research and Evaluation, Yale New Haven Hospital in New Haven, Connecticut. It was published online on November 6 as a research letter in JAMA Oncology.

LIMITATIONS:

The descriptive design without adjustment for confounding factors limited causal inference. Additionally, inherent constraints of electronic health records could lead to potential misclassification, and researchers were unable to distinguish between active treatment and maintenance status in patients with cancer.

DISCLOSURES:

Michaela Dinan, PhD, reported receiving grants through Yale University from the National Cancer Institute and the American Cancer Society outside the submitted work. Joseph Ross, MD, MHS, disclosed receiving grants from multiple organizations, including the FDA and Johnson & Johnson, and serving as an expert witness in a qui tam suit. Ania Jastreboff, MD, PhD, reported receiving trial funds paid to the institution from various pharmaceutical companies and personal fees from multiple organizations. Harlan Krumholz, MD, SM, disclosed receiving personal fees from various health-related companies and grants through Yale University from several pharmaceutical companies. Yuan Lu, ScD, reported receiving grants from multiple organizations outside the submitted work.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.