Research presented at ENDO 2025 revealed that obesity-related cancer deaths in the U.S. have tripled over the past two decades. Thirteen types of obesity-related cancers now account for 40% of all cancer diagnoses. While not a new revelation, the data serves as a stark reminder for oncologists, especially given that more than 40% of Americans are living with obesity. It highlights a growing public health concern.
Obesity remains a stigmatized condition, despite its complex causes, including genetic, physiological, and hormonal factors. As obesity rates rise, the medical community is seeking new treatment approaches that reflect its connection to cancer. But before treatment can advance, a deeper understanding of how obesity drives tumor development is essential.
Obesity and tumor development
While the study presented at ENDO 2025 illustrated the link between obesity and cancer, understanding the specific mechanisms that cause that connection is more opaque. Below are several key pathways currently recognized by researchers:
- Inflammation: Obesity triggers chronic, low-grade inflammation throughout the body. This persistent inflammatory state has been linked to increased cancer risk and progression, particularly in breast, colorectal, and other obesity-related cancers.
- Insulin resistance: Obesity-induced inflammation can disrupt the body’s ability to respond to insulin, leading to insulin resistance. In turn, the body produces more insulin, a hormone that, at elevated levels, can promote the development and growth of cancer cells.
- Growth hormones: Excess body fat can increase levels of certain growth hormones. These hormones stimulate cell division, which raises the likelihood of mutations and cancer development.
Emerging treatment approaches
As our understanding of obesity’s role in cancer deepens, new treatment strategies are beginning to emerge that target its underlying biological mechanisms. Below are a few examples of new and promising approaches currently under investigation.
One area that has shown promise is metabolic interventions, e.g., dietary changes, pharmacotherapy, and bariatric surgery. These approaches are especially valuable when lifestyle modifications alone aren’t enough. GLP-1 receptor agonists (e.g., Ozempic [semaglutide], Mounjaro [tirzepatide]), originally developed for diabetes, have demonstrated significant weight loss outcomes. Early studies suggest these drugs may also reduce tumor growth by modulating inflammation and metabolic pathways, though more research is needed.
While addressing obesity is critical to reducing cancer risk, it’s only one side of the equation. Many patients are already navigating a cancer diagnosis where obesity and related lifestyle factors complicate treatment decisions. Obesity can increase surgical risk, limit treatment options, and contribute to more aggressive disease in some cancers.
As a result, advancing cancer therapies that are adaptable to patients’ diverse health profiles, including those living with obesity, is essential. An example of this is diffusing alpha-emitters radiation therapy, which delivers high-energy alpha particles directly into tumors. Unlike traditional radiation, it targets cancer cells with minimal damage to nearby tissue, which is an important advantage for patients with obesity, who may face surgical challenges or have more complex anatomy.
A path forward
Addressing the obesity-cancer connection begins with awareness. The more we understand how excess weight influences cancer risk, the better equipped we are to intervene early, tailor treatment, and support long-term health.
Continued research, earlier screening, and open provider-patient communication will be key to shifting outcomes. With the right tools, we can take proactive steps to prevent cancer and promote better health for individuals and the broader population.
Photo: wildpixel, Getty Images
Dr. Robert Den is a Radiation Oncologist and has served as Chief Medical Officer of Alpha Tau for five years. He has a BS from Yale University, a doctorate from Harvard Medical School, and nearly 17 years of experience as an associate professor at Thomas Jefferson University.
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