Pieter De Richter, Ipsos Global Healthcare Monitors July 2026
Why are oncologists prescribing GLP-1s?
Pieter De Richter - Ipsos Global Healthcare Monitors
July 2026
Pieter De Richter - Ipsos Global Healthcare Monitors October 2025
Why are oncologists prescribing GLP-1s?
Pieter De Richter Ipsos Global Healthcare Monitors July 2026
Lizy Gill, Ipsos MASH Therapy Monitor October 2025
Cancer and obesity form two of the defining health epidemics of our time. At their intersection, Ipsos data reveals:
76% of oncologists surveyed prescribe GLP-1s to their cancer patients.
Reasons for doing so include boosting the patient’s overall health status and maximising cancer therapy efficacy.
Concerns exist regarding unknown drug interactions and clarity of GLP-1 effects on cancer outcomes.
Introduction
GLP-1 agonists, often simply referred to as GLP-1s, are everywhere these days. Helping people lose weight, reduce their consumption of certain foods and drinks, and generally improve their cardiometabolic health, they are rapidly reshaping not just the healthcare space, but many other industries as well.
Given the increasing prevalence of weight-related conditions and the rapid uptake of GLP-1s on the one hand, and the increasing incidence of cancer on the other hand, it was always inevitable that these two worlds would end up colliding.
Based on responses from physicians at the front-line of cancer treatment, this paper explores precisely what is happening at the intersection between GLP-1 usage and cancer treatment.
Whether you are a professional active in either the oncology or the weight management field, you are directly or indirectly impacted by cancer or weight changes, or would simply like to understand how seemingly different medical disciplines can end up pulling each other into their respective orbits, this paper is for you.
The extent of GLP-1 usage among oncologists
In June 2025, Ipsos contacted 92 oncologists and asked them: have you personally prescribed a GLP-1 to any of your patients in the past 3 months? 67% said yes. When we repeated the survey in May 2026 (with 72 respondents), the percentage had increased to 76%.
Fig 1: % surveyed physicians prescribing GLP-1s to their cancer patients
2025
% physicians
2026
% physicians
Source: Survey conducted by Medefield on behalf of Ipsos. (June 2025, 92 oncologists/haem-oncologists across US, UK, France, Germany Italy and Spain, who treat cancer patients, providing perceptions online. Survey repeated May 2026 among 72 oncologists/haem-oncologists). Full question stipulates any prescribing of GLP-1s to cancer patients in 3 months prior to survey completion. Data are © Medefield 2026, all rights reserved.
Based on data from Ipsos’ Global Oncology Monitor, we knew GLP-1s were starting to play a role in oncology. But that is a staggering percentage for a group of specialists who, on the surface, wouldn’t be expected to be prescribing weight management or diabetes medications.
What could explain these results?
#1: Improve overall health
The number one reason the oncologists prescribed a GLP-1 to their cancer patients was to improve overall health/ performance status of the patient, and hence improve outcomes. It is a relatively well-studied fact that being overweight is negatively correlated with overall survival (OS), and associated with an increased risk of recurrence, for cancer survivors1. More recently, studies have shown that the use of GLP-1s in cancer patients can improve long-term outcomes2,3,4. Furthermore, it has been postulated that this benefit isn’t just due to the weight loss benefits of GLP-1s: effects such as improved kidney function, reduced insulin resistance and improved cardiac function may further contribute to the positive effects that have been observed.
#2: Counteract weight gain as a result of cancer treatment
The second most frequent mention was the use of GLP-1s to prevent weight gain as a result of certain anti-cancer treatments. A number of these drugs can indeed result in weight gain, either indirectly (e.g. increasing fatigue which results in less activity) or more directly (e.g. increasing food cravings). Hormone therapies, often used in breast and prostate cancer, are notorious for this side-effect. Tyrosine kinase inhibitors, used to treat lung and other cancers, can also lead to weight gain. Giving GLP-1s alongside these drugs may help counteract these effects and ensure the patient stays at a healthy weight, in turn improving their long-term outcomes (see #1).
#3: Maximise effects of cancer treatments
There is increasing evidence that GLP-1 usage may result in short-term improvements in patients’ responses to anti-cancer drugs, during the course of treatment itself. Indeed, the third most frequently mentioned reason by our surveyed oncologists in 2025 (and fourth in 2026) was as an adjunct to anti-cancer therapy to reduce the aggressiveness of cancer.
Several papers have explored this further, with findings ranging from GLP-1s enhancing the effectiveness of gemcitabine in pancreatic cancer5, to GLP-1s being used alongside neoadjuvant therapy (chemotherapy that is given prior to surgery) in locally advanced rectal cancer6. The mechanisms are still being investigated, but potential pathways include the reduction of inflammation associated with visceral fat, direct activation of apoptosis (programmed cell death of cancer cells) and increased immune cell activity (responsible for eliminating cancer cells).
#4 Decrease toxicity of cancer treatments
Our oncologists also indicated GLP-1s can be used to decrease the risk of other toxicities associated with anti-cancer drugs (e.g. cardiotoxicity). In fact, in the 2026 survey, oncologists mentioned this almost as frequently as preventing weight gain.
GLP-1s are more than just weight loss drugs, and their positive effects can extend beyond – or even take place in absence of – losing weight. Several anti-cancer drugs, such as trastuzumab and doxorubicin, are known to have the potential to cause cardiotoxicity; GLP-1s can potentially reduce this risk when prescribed concurrently.
#5 Prevent surgical complications
Weight loss (including GLP1-induced loss) reduces visceral fat, can shorten surgery time, can lower bleeding, and hence can reduce morbidity rate during cancer surgery. Therefore, GLP-1s may improve outcomes in those cancer patients who are candidates for surgery.
Fig 2: Reasons for prescribing GLP-1s to cancer patients
Source: Survey conducted by Medefield on behalf of Ipsos. (June 2025, 92 oncologists/haem-oncologists across US, UK, France, Germany Italy and Spain, who treat cancer patients, providing perceptions online. Survey repeated May 2026 among 72 oncologists/haem-oncologists). Full question stipulates any prescribing of GLP-1s to cancer patients in 3 months prior to survey completion. Data are © Medefield 2026, all rights reserved.
Given all of the above, it is perhaps not that surprising that the willingness to prescribe GLP-1s is so prevalent amongst the oncologists: this drug class can improve short and long-term outcomes, can reduce side-effects, and can prevent complications. Knowing this, one could conceivably make the case that all cancer patients should be prescribed GLP-1s.
But that’s not the reality…
Potential pitfalls
Paradoxically, while the oncologists are seemingly proactive in prescribing GLP-1s to their cancer patients and hence can drive increased GLP-1 prescriptions, we see a different mindset in those cases where patients were already on a GLP-1 at the time they were diagnosed with cancer. The majority of surveyed respondents stated they do at times take patients off GLP-1s during the course of their anti-cancer treatment.
Fig 3: % physicians who take patients off GLP-1s during the course of their anti-cancer treatment
Source: Survey conducted by Medefield on behalf of Ipsos. (June 2025, 92 oncologists/haem-oncologists across US, UK, France, Germany Italy and Spain, who treat cancer patients, providing perceptions online. Survey repeated May 2026 among 72 oncologists/haem-oncologists). Data are © Medefield 2026, all rights reserved.
Instead of taking patients off GLP-1s, an alternative strategy is to avoid prescribing certain anti-cancer drugs to those patients. Indeed, 31% of respondents in 2025 (increasing to 40% in 2026) stated they sometimes avoid prescribing certain anti-cancer medications to patients on GLP-1s, due to their potential to worsen certain anti-cancer drug side effects. GLP-1s can come with side effects of their own that may potentially worsen cancer treatment side effects, e.g. nausea, too much weight loss.
Fig 4: Stated impact of GLP-1s on cancer treatment selection
Source: Survey conducted by Medefield on behalf of Ipsos. (June 2025, 92 oncologists/haem-oncologists across US, UK, France, Germany Italy and Spain, who treat cancer patients, providing perceptions online. Survey repeated May 2026 among 72 oncologists/haem-oncologists). Data are © Medefield 2026, all rights reserved.
Other reasons why GLP-1s may not always be suitable in cancer treatment scenarios include:
- Possible thyroid complications: Patients with a personal or family history of medullary thyroid carcinoma (the most common type of thyroid cancer) and patients with multiple endocrine neoplasia syndrome type 2 (a rare inherited condition that can cause thyroid and other tumours) should not be taking GLP-1s.
- Unwanted drug interactions: While no specific drug interactions have been conclusively identified between GLP-1s and anti-cancer drugs, they certainly should not be discounted, given the rapidly growing number of drugs in both categories. 27% of the oncologists in 2025 stated they were concerned about potential drug interactions between GLP-1s and anti-cancer therapies (increasing to 33% in 2026).
Whether prescribing them or not, what is the general mood surrounding GLP-1s?
There’s both enthusiasm and reticence. 39% of the respondents in 2025 agreed with the statement I am interested in GLP-1s for their potential anti-tumour effects, beyond weight management. This aligns well with the aforementioned reasons for prescription. However, the two next most commonly agreed with statements were, in order:
- The impact of GLP-1s on cancer outcomes is not yet clear to me (37%, rising to 49% in 2026)
- I need more guidance on how to monitor patients on both GLP-1s and anti-cancer therapies (34%)
Furthermore, 30% said they would like to have more data on the effects of GLP-1s on their cancer patients - this increased to 50% in 2026, making it the most agreed with statement vs 2025. Clearly, there is a lot of – arguably growing - uncertainty in this space among oncologists. It will take time for the exact role of this rapidly expanding drug class in the cancer setting to be fully determined. One thing is clear, however: GLP-1s are making an impact in this space, one way or another. In 2025, only 8% felt these drugs were not relevant to their oncology practice; by 2026, this percentage had dropped to just 4%.
Fig 5: % physicians agreeing with statements regarding GLP-1s and their clinical oncology practice
Source: Survey conducted by Medefield on behalf of Ipsos. (June 2025, 92 oncologists/haem-oncologists across US, UK, France, Germany Italy and Spain, who treat cancer patients, providing perceptions online. Survey repeated May 2026 among 72 oncologists/haem-oncologists). Data are © Medefield 2026, all rights reserved.
Moving forward
On the surface, cancer and obesity appear to have little in common. One is driven by genetic mutations, the other by calorific excess. However, when we look beyond those overly simple statements, the situation becomes more nuanced. Cancer is a disease of rapidly dividing, undifferentiated cells. These cells thrive in an inflammatory, metabolically unstable environment. This, in turn, is a hallmark of obesity as a disease.
The rapid rise of GLP-1 agonists to combat the growing obesity problem is likely to reduce the incidence of certain cancers; this is a relatively well-established prediction. What is now also becoming clear, however, is that – despite a number of potential complications – GLP-1s may be used to help improve the outcomes of cancer patients.
What the cancer-treaters of today need now are clear parameters of when to use – and when not to use – GLP-1s. Those in the industry that can provide such clarity will surely be thought of as vanguards across this particular treatment intersection of our time.
Insights into the evolving usage of GLP-1 therapies are captured in the following syndicated Ipsos solutions:
- Obesity & Cardiometabolic Disease Therapy Monitor
- Global Consumer Obesity Monitor
- Metabolic Dysfunction-Associated Steatohepatitis (MASH) Therapy Monitor
- Global Oncology Monitor
For more information, contact Pieter.DeRichter@ipsos.com
To learn about the link between obesity and cancer risk, read: Does Everything Really Cause Cancer?
References
1. Petrelli, F. et al. (2021) ‘Association of Obesity With Survival Outcomes in Patients With Cancer’, JAMA Network Open, 4(3), p. e213520. Available at: https://doi.org/10.1001/jamanetworkopen.2021.3520.
2. Radwan, R.M. et al. (2025) ‘GLP-1 RA Use and Survival Among Older Adults With Cancer and Type 2 Diabetes’, JAMA Network Open, 8(7), p. e2521887. Available at: https://doi.org/10.1001/jamanetworkopen.2025.21887.
3. Gregerson, E. (2026) GLP-1s and cancer outcomes: What new research shows, Becker’s Hospital Review. Available at: https://www.beckershospitalreview.com/pharmacy/glp-1s-and-cancer-outcomes-what-new-research-shows/ (Accessed: 15 June 2026).
4. Parker, J. (2026) ASCO 2026: GLP-1s could reduce the risk of some obesity-related cancers progressing, Oncology Central. Available at: https://www.oncology-central.com/asco-2026-glp-1s-could-reduce-the-risk-of-some-obesity-related-cancers-progressing/ (Accessed: 15 June 2026).
5. Zhao, H. et al. (2020) ‘Activation of GLP-1 receptor enhances the chemosensitivity of pancreatic cancer cells’, Journal of Molecular Endocrinology, 64(2), pp. 103–113. Available at: https://jme.bioscientifica.com/view/journals/jme/64/2/JME-19-0186.xml.
6. Temperley, H.C. et al. (2026) ‘Evaluating the impact of GLP-1 receptor agonists in combination with total neoadjuvant therapy for locally advanced rectal cancer’, British Journal of Surgery, 113(4). Available at: https://doi.org/10.1093/bjs/znag029.
About the Research
Survey conducted by Medefield on behalf of Ipsos. 92 oncologists and haem-oncologists across US, UK, France, Germany Italy and Spain, who treat cancer patients, completed an online survey to provide their perceptions of GLP-1 usage in cancer patients. Fieldwork was conducted in June 2025. The survey was repeated among 72 oncologists and haem-oncologists across the same regions in May 2026. Data are © Medefield 2026, all rights reserved.
