GLP-1s in Oncology: Nursing Insights and Breast Cancer Survivorship

For Patricia Jakel, MN, RN, AOCN, an oncology nurse consultant and co-editor in chief of Oncology Nursing News, the struggle with weight gain was not a matter of willpower, but biology. Like many patients who are diagnosed with lobular breast cancer, Jakel found that the very treatments saving her life were also working against her metabolic health.

Despite the common clinical refrain to simply "watch your diet and exercise," Jakel, like 41% to 65% of women on aromatase inhibitors or tamoxifen, faced a persistent weight gain of 7 to 10 pounds. “For women doing that and still having weight gain, you’re frustrated,” she explains, noting that the estrogen stored in fat cells remains a "beacon" for potential recurrence.

A new frontier in survivorship

The emergence of glucagon-like peptide-1 (GLP-1) receptor agonists has shifted from the periphery of diabetes management to a central focus of oncology research. These medications mimic gut hormones to regulate blood sugar and slow digestion, offering a potential solution for the neuroendocrine disruption caused by cancer treatments.

According to Sriram Machineni, MD, Director of the Fleischer Institute Medical Weight Center at Montefiore Einstein, treatments like tamoxifen deprive the body of estrogen, which is critical for the brain's sensitivity to leptin, the hormone that signals fullness. This creates a "perfect storm" where survivors feel hungrier while their bodies burn energy less effectively. GLP-1s bypass these disrupted pathways to directly activate satiety signals, succeeding where traditional lifestyle changes often fail.

Emerging clinical evidence

Real-world data presented at the American Society of Clinical Oncology (ASCO) 2026 Annual Meeting have bolstered interest in these agents:

• Reduced risk: A Penn Medicine analysis of over 110,000 women found that GLP-1 users were 30% less likely to develop breast cancer.
• Mortality benefits: Research from Harvard University and the Cleveland Clinic observed a 34% to 35% reduction in death rates across various solid tumor types among GLP-1 users.
• Improved survival: An MD Anderson study of over 1,000 breast cancer survivors confirmed improved all-cause survival, likely due to enhanced cardiovascular health, though it did not significantly reduce the risk of breast cancer recurrence.

The oncology nursing perspective

Jakel emphasizes that as these drugs become more prevalent, oncology nurses must be prepared to manage a new set of side effects. Beyond standard gastrointestinal issues like nausea and constipation, she highlights the risk of muscle wasting and the intense lifestyle requirements of these medications. Patients may need to consume protein for 70% to 90% of their diet and engage in significant weightlifting to maintain lean muscle mass.

Furthermore, Jakel notes the additive effect of fatigue. “A lot of women suffer from fatigue from the GLP-1s, and if you're already on an AI and a CDK4 inhibitor, you're already dealing with fatigue,” she says. Nurses play a critical role in educating survivors that while GLP-1s are a "beacon" of hope, they require rigorous self-care.

Barriers to equity and care

Despite the clinical promise, Jakel is deeply concerned about "an inequity that is going to happen" regarding drug access. When Jakel transitioned to Medicare, she lost access to manufacturer discounts on GLP-1 treatment, facing a $1,200 monthly out-of-pocket cost. This financial toxicity often drives patients toward compounding pharmacies, which not everyone can afford.

There also remains a lack of clarity regarding which provider should manage these prescriptions. While some primary care doctors handle them, Jakel questions if the responsibility should fall to oncologists. “Is it a form of prevention? Is it a form of treatment for some women?” she asks, noting that many survivorship clinics currently refuse to manage the medications.

A call for targeted research

Neil M. Iyengar, MD, director of Survivorship Services at Winship Cancer Institute of Emory University, a clinical member of Winship’s Glenn Family Breast Center, an associate professor and co-director of the Breast Medical Oncology Program in the Department of Hematology and Medical Oncology at Emory University School of Medicine, adds a note of caution regarding timing, stating there is a lack of robust data on the safety of GLP-1s during active chemotherapy or immunotherapy. Additionally, hormone therapy may make GLP-1s less effective, with survivors often losing less than 5% of their body weight compared to 10%-15% in the general population.

Jakel’s personal and professional mission is to ensure that research keeps pace with patient needs. She has even lobbied researchers like Iyengar to include specific subsets of patients, such as those with lobular breast cancer, in upcoming studies. Currently, clinical trials specifically investigating GLP-1s in this population are scarce. For Jakel, the goal is to move the conversation beyond simple weight loss toward a future where every survivor has an equitable chance to thrive.

References

1. McDonald E, et al. GLP-1 use linked to lower breast cancer incidence in large cohort study. Presented at: 2026 American Society of Clinical Oncology (ASCO) Annual Meeting; June 2, 2026. Abstract 10506.
2. Sukumar JS, Raghavendra AS, Pasyar S, et al. Weight loss patterns and clinical outcomes of GLP1 receptor agonists in breast cancer survivors. Cancer Res Commun. 2026;6(3):447-455. doi:10.1158/2767-9764.CRC-25-0554.
3. Paulus J, et al. Impact of GLP-1RA use in oncology patients on overall survival. Presented at: 2026 American Society of Clinical Oncology (ASCO) Annual Meeting; June 2026.
4. Cleveland Clinic. GLP-1RA use and metastatic progression across obesity-related solid tumors. Presented at: 2026 American Society of Clinical Oncology (ASCO) Annual Meeting; June 2026.
5. Shen S, Chen Y, Carpio A, et al. Incidence, risk factors, and management of alpelisib-associated hyperglycemia in metastatic breast cancer. Cancer. 2023;129(24):3854-3861.
6. Piersol B. Cancer benefits and risks from Ozempic, Wegovy, and other weight loss drugs. Memorial Sloan Kettering Cancer Center. March 10, 2026. Accessed July 8, 2026. https://www.mskcc.org/news/cancer-benefits-and-risks-from-ozempic-wegovy-and-other-weight-loss-drugs.
7. Mapes D. What cancer researchers, clinicians and patients say about ‘game-changing’ GLP-1s. Fred Hutch News Service. May 6, 2026. Accessed July 8, 2026. https://www.fredhutch.org/en/news/center-news/2026/05/cancer-researchers-clinicians-patients-glp1s-weight-loss-drugs.html.