Diabetes and Cancer.

Diabetes and cancer are common conditions, affecting 384 million and 33 million people worldwide, respectively. Therefore, there is great potential for overlap, with people with diabetes also developing cancer and vice versa. However, people with diabetes may be at increased risk of developing cancer when compared with the general population. This is due to both shared risk factors associated with the two diseases and the metabolic derangements associated with diabetes, such as hyperglycaemia, insulin resistance, hyperinsulinaemia and oxidative stress. Glucose-lowering therapies may influence the risk of cancer in people with type 2 diabetes due to these therapies' effects on risk factors that are common to both conditions, including hyperglycaemia and obesity, as well as effects that are specific to the class of drug or drugs. Drugs that reduce circulating insulin levels, such as metformin, may reduce cancer risk, and drugs that increase circulating insulin levels, including exogenous insulin and insulin secretagogues, may increase cancer risk. The influence of glucose-lowering therapies on cancer risk may become an important consideration when selecting glucose-lowering therapies to treat people with type 2 diabetes and a high risk of cancer occurrence or recurrence.