Diabetes and Cancer: Risk, Challenges, Management and Outcomes

Simple Summary: Diabetes mellitus is a common disease in patients with cancer. It is a risk factor for certain cancers such as pancreatic, liver, colon, breast, and endometrial cancer. Furthermore, several new cancer treatments or the use of steroids may unmask underlying diabetes or aggravate preexisting diabetes. Evidence suggests that patients with cancer and diabetes have higher cancer-related mortality. Moreover, concurrent complications associated with diabetes in patients with cancer may influence the choice of cancer therapy. This review highlights the relationship between diabetes and cancer and various aspects of the management of diabetes in patients with cancer. Background: Diabetes mellitus and cancer are commonly coexisting illnesses, and the global incidence and prevalence of both are rising. Cancer patients with diabetes face unique challenges. This review highlights the relationship between diabetes and cancer and various aspects of the management of diabetes in cancer patients. Methods: A literature search using keywords in PubMed was performed. Studies that were published in English prior to July 2021 were assessed and an overview of epidemiology, cancer risk, outcomes, treatment-related hyperglycemia and management of diabetes in cancer patients is provided. Results: Overall, 8-18% of cancer patients have diabetes as a comorbid medical condition. Diabetes is a risk factor for certain solid malignancies, such as pancreatic, liver, colon, breast, and endometrial cancer. Several novel targeted compounds and immunotherapies can cause hyperglycemia. Nevertheless, most patients undergoing cancer therapy can be managed with an appropriate glucose lowering agent without the need for discontinuation of cancer treatment. Evidence suggests that cancer patients with diabetes have higher cancer-related mortality; therefore, a multidisciplinary approach is important in the management of patients with diabetes and cancer for a better outcome. Conclusions: Future studies are required to better understand the underlying mechanism between the risk of cancer and diabetes. Furthermore, high-quality prospective studies evaluating management of diabetes in cancer patients using innovative tools are needed. A patient-centered approach is important in cancer patients with diabetes to avoid adverse outcomes.