A new study published in Obesity Surgery in June 2026 has highlighted an association between metabolic and bariatric surgery and a lower risk of developing certain cancers in adults living with severe obesity.
The large real-world analysis compared 90,192 patients who underwent metabolic and bariatric surgery with a matched group of patients who received structured dietary counselling or education. All patients included had a BMI of 35 kg/m² or above and no previous history of cancer.
Researchers followed patients for up to five years to assess differences in the development of new cancers.
How Obesity Can Influence Long-Term Health and Cancer Risk
Higher levels of body fat can affect several biological processes that influence long-term health.
Research suggests obesity may contribute to increased cancer risk through changes such as chronic inflammation, insulin resistance, hormone changes, and altered signals produced by fat tissue.
Because of these connections, researchers are continuing to study whether treatments that improve obesity and metabolic health may also affect future disease risk.
What Did the Study Find?
After carefully matching patients for factors including existing health conditions, smoking, alcohol use, hormone exposure, medication use, and cancer screening history, researchers found that bariatric surgery was associated with lower rates of several cancers compared with dietary counselling alone.
The study reported:
Obesity-related cancers:
1.0% of bariatric surgery patients developed obesity-related cancers compared with 1.2% of patients receiving dietary counselling.
Solid tumours:
2.2% of bariatric surgery patients developed solid tumours compared with 2.5% in the dietary counselling group.
Blood-related (haematological) cancers:
0.26% after bariatric surgery compared with 0.28% after dietary counselling.
Researchers also observed significant reductions in the risk of several obesity-related cancers, including:
- Breast cancer
- Colorectal cancer
- Endometrial cancer
- Pancreatic cancer
- Liver cancer
Why Might Bariatric Surgery Be Linked with Lower Cancer Risk?
The exact relationship between bariatric surgery and cancer risk is still being researched. However, experts believe improvements in metabolic health may play an important role.
Bariatric procedures, including gastric bypass and sleeve gastrectomy, can support significant and sustained weight loss while also improving many of the biological changes associated with obesity. These changes may include improvements in insulin regulation, inflammation levels, and hormone balance, factors that are also linked to cancer development.
Bariatric Surgery: Looking Beyond Weight Loss
For many patients, weight loss surgery is not only about changing a number on the scales.
Bariatric surgery is designed to support long-term weight management and improve obesity-related health conditions, helping patients work towards better overall health and quality of life.
At Phoenix Health, our experienced bariatric team understands that every patient’s journey is different. We provide specialist assessment, personalised bariatric treatment options, and ongoing support to help patients make informed decisions about their health.
What These Findings Mean for Patients
This study is an important addition to our understanding of the relationship between obesity treatment and long-term health. However, as an observational study, it cannot prove that bariatric surgery directly prevents cancer, and researchers have highlighted the need for further long-term studies.
What it does show is that metabolic and bariatric surgery was associated with lower rates of several cancers in adults living with severe obesity, adding to growing research that looks at the wider health impact of treating obesity beyond weight loss alone.
Reference:
Ghusn, W. et al. (2026) “Metabolic and Bariatric Surgery vs. Dietary Counseling in Adults with Severe Obesity: Risk of De Novo Malignancy in a Propensity-Matched Multicentered Real-World Analysis” Obesity Surgery. https://doi.org/10.1007/s11695-026-08787-y
Medically Reviewed by Lujain Alhassan, BSc, ANutr
Registered Associate Nutritionist and Bariatric Nutrition
