Challenges in the management of people with diabetes and cancer

Although micro‐ and macrovascular complications of diabetes are the most important cause of mortality and morbidity in people with diabetes, it is increasingly recognized that diabetes increases the risk of developing cancer. Diabetes and cancer commonly co‐exist, and outcomes in people with both conditions are poorer than in those who have cancer but no diabetes. There is no randomized trial evidence that treating hyperglycaemia in people with cancer improves outcomes, but therapeutic nihilism should be avoided, and a personalized approach to managing hyperglycaemia in people with cancer is needed. This review aims to outline the link between diabetes therapies and cancer, and discuss the reasons why glucose should be actively managed people with both. In addition, we discuss clinical challenges in the management of hyperglycaemia in cancer, specifically in relation to glucocorticoids, enteral feeding and end‐of‐life care. What's new? Cancer is common among people diagnosed with diabetes, and hyperglycaemia is a common adverse effect of a number of anti‐cancer therapies. Overall outcomes of cancer therapy are improving, and there is a growing need to recognize people who are ‘living with and beyond cancer’. Although there is little evidence to suggest that treating hyperglycaemia improves outcomes in people with diabetes and cancer, it is important to personalize treatment targets for hyperglycaemia according to the person's prognosis, comorbidity and personal preferences. People with diabetes are more likely to have deterioration in comorbidities when undergoing cancer chemotherapy. Cyclical regimes, enteral feeding and end‐of‐life care pose particular challenges in people with diabetes and cancer.