Can chemotherapy (chemo) cause diabetes?

From the Guidelines

Chemotherapy can increase the risk of developing diabetes, particularly in patients receiving glucocorticoids like dexamethasone, as evidenced by a study published in The Lancet Diabetes and Endocrinology in 2021 1. This risk is higher for patients with pre-existing risk factors for diabetes, such as obesity or a family history of diabetes. The mechanism involves chemotherapy drugs interfering with insulin production or increasing insulin resistance, which can lead to elevated blood sugar levels. According to a study published in the Journal of Clinical Oncology in 2021, insulin therapy should be used to treat significant hyperglycemia, with a starting total daily requirement estimated at 0.3-0.4 units/kg/d 1. Patients undergoing chemotherapy should have their blood sugar monitored regularly, especially if they're receiving steroids or have other risk factors for diabetes. If symptoms like increased thirst, frequent urination, unexplained weight loss, or extreme fatigue occur, patients should discuss these with their healthcare provider as they could indicate high blood sugar levels. It is essential to note that the effect of chemotherapy on blood sugar levels can be temporary, but in some cases, the diabetes may persist, highlighting the need for ongoing monitoring and management. In cases where new-onset hyperglycemia occurs without risk factors for type 2 diabetes, there should be a high suspicion for checkpoint inhibitor-associated diabetes mellitus (CIADM), which requires prompt diagnosis and treatment with insulin therapy, as well as endocrinology consultation 1. Overall, the risk of developing diabetes due to chemotherapy, particularly with glucocorticoid use, necessitates careful monitoring and management to prevent complications and ensure the best possible outcomes for patients. Key considerations include:

• Regular blood sugar monitoring for patients undergoing chemotherapy, especially those receiving steroids
• Prompt recognition and treatment of hyperglycemia
• Consideration of CIADM in cases of new-onset hyperglycemia without risk factors for type 2 diabetes
• Collaboration with endocrinology specialists for complex cases or suspected CIADM.

From the Research

Chemotherapy and Diabetes

• Chemotherapy (chemo) can cause diabetes in some patients, as certain chemotherapy drugs and steroids can lead to hyperglycemia (high blood sugar levels) 2, 3, 4.
• The incidence of hyperglycemia during chemotherapy varies, but it is estimated to occur in approximately 10% to 30% of patients 2.
• Certain chemotherapy drugs, such as glucocorticoids and L-asparaginase, are well-known to cause acute hyperglycemia during chemotherapy 2.
• Long-term hyperglycemia is also frequently observed, especially in patients with hematologic malignancies treated with L-asparaginase-based regimens and total body irradiation 2.

Mechanisms and Risk Factors

• The mechanisms of chemotherapy-induced hyperglycemia include increased insulin resistance, diminished insulin secretion, and exaggerated hepatic glucose output 2.
• The use of certain anti-diabetic drugs, such as insulin and insulin analogs, can also influence the risk of hyperglycemia and chemosensitivity of cancer cells 5.
• The cumulative dose of dexamethasone, a common antiemetic drug used in chemotherapy, is associated with an increased risk of steroid-induced diabetes 4.

Management and Monitoring

• Screening strategies for hyperglycemia include random glucose testing, hemoglobin A1c testing, oral glucose loading, and fasting plasma glucose screens 2.
• The management of hyperglycemia starts with insulin or sulfonylurea, depending on the type, dose, and delivery of the glucocorticoid formulation 2.
• Metformin is a safe and effective option for managing therapy-induced hyperglycemia in patients with acute lymphoblastic leukemia 6.
• Frequent monitoring and proper management of hyperglycemia are important for promoting the efficacy of anti-cancer therapy and improving patients' quality of life 2, 3.