Obesity and Cancer: A Current Overview of Epidemiology, Pathogenesis, Outcomes, and Management

SIMPLE SUMMARY: Obesity has been linked to several common cancers including breast, colorectal, esophageal, kidney, gallbladder, uterine, pancreatic, and liver cancer. Obesity also increases the risk of dying from cancer and may influence the treatment choices. About 4–8% of all cancers are attributed to obesity. The underlying mechanism of obesity causing cancer is complex and is incompletely understood. Lifestyle changes that include diet, exercise, and behavior therapy are the mainstay of interventions. Drug therapy and weight reduction surgery result in a more rapid weight loss and may be used for a subgroup of cancer survivors with obesity. This review highlights the epidemiology and the risk associated with the development and recurrence of cancer in obese individuals and the management of obesity. ABSTRACT: Background: Obesity or excess body fat is a major global health challenge that has not only been associated with diabetes mellitus and cardiovascular disease but is also a major risk factor for the development of and mortality related to a subgroup of cancer. This review focuses on epidemiology, the relationship between obesity and the risk associated with the development and recurrence of cancer and the management of obesity. Methods: A literature search using PubMed and Google Scholar was performed and the keywords ‘obesity’ and cancer’ were used. The search was limited to research papers published in English prior to September 2022 and focused on studies that investigated epidemiology, the pathogenesis of cancer, cancer incidence and the risk of recurrence, and the management of obesity. Results: About 4–8% of all cancers are attributed to obesity. Obesity is a risk factor for several major cancers, including post-menopausal breast, colorectal, endometrial, kidney, esophageal, pancreatic, liver, and gallbladder cancer. Excess body fat results in an approximately 17% increased risk of cancer-specific mortality. The relationship between obesity and the risk associated with the development of cancer and its recurrence is not fully understood and involves altered fatty acid metabolism, extracellular matrix remodeling, the secretion of adipokines and anabolic and sex hormones, immune dysregulation, and chronic inflammation. Obesity may also increase treatment-related adverse effects and influence treatment decisions regarding specific types of cancer therapy. Structured exercise in combination with dietary support and behavior therapy are effective interventions. Treatment with glucagon-like peptide-1 analogues and bariatric surgery result in more rapid weight loss and can be considered in selected cancer survivors. Conclusions: Obesity increases cancer risk and mortality. Weight-reducing strategies in obesity-associated cancers are important interventions as a key component of cancer care. Future studies are warranted to further elucidate the complex relationship between obesity and cancer with the identification of targets for effective interventions.