Endocrine Side Effects of Cancer Treatment in Type 1 Diabetes

Innovations in Diabetes & Metabolic Care | Summer 2024

A cancer diagnosis is a life-altering event that takes a significant toll on an individual’s physical and emotional well-being. Cancer treatment can also present unique endocrine challenges, exacerbating Type 1 diabetes mellitus (DM) or, in rare cases, causing new-onset insulin deficiency.

Lily Tranchito, DO

At the University Hospitals Diabetes and Metabolic Care Center, experts are available to guide individuals through their treatment plan, monitor metabolic symptoms and keep blood glucose at safe levels.

“We counsel patients based on what medications they are receiving for their cancer, specifically when they are receiving steroids,” says Lily Tranchito, DO, an endocrinologist within the UH Diabetes and Metabolic Care Center. “Steroids significantly raise blood sugar in a unique pattern and require careful management.”

Typically, patients with Type 1 DM receive daily basal and bolus insulin. Dr. Tranchito explains that during chemotherapy, individuals often need a third type, NPH insulin, to be administered at the same time as steroid dosing because both medications have a similar time of action in the body.

It is also important to understand how patients with Type 1 DM manage their mealtime insulin while undergoing cancer treatment. “Some individuals count carbohydrates, and others are on fixed-meal dosing and give themselves specific insulin units before each meal,” Dr. Tranchito says. “During chemotherapy, symptoms like reduced appetite or nausea often affect how much people eat and require changes to their insulin regimen.” 

Throughout cancer treatment, a patient’s status can change quickly. Glucose levels should be carefully tracked to avoid steroid-induced hyperglycemia or dangerous drops in blood sugar that can lead to hypoglycemic shock. The American Diabetes Association recommends that everyone with Type 1 DM use an automated insulin delivery system.

“A hybrid, closed-loop system with a continuous glucose monitor and insulin pump is considered the standard of care and should be considered for all patients with Type 1 diabetes,” Dr. Tranchito says. “We have an excellent team within our diabetes and metabolic center that can provide multiple touchpoints for people to receive the care, education and follow-up they need to manage their Type 1 diabetes through their cancer journey and beyond.”

Immune Checkpoint Inhibitors

Some types of cancer are treated with immune checkpoint inhibitors (ICIs), a newer class of immunotherapy medications that work by blocking negative checkpoint proteins that stop T-cells from attacking cancer cells and boosting the body’s immune response. While early clinical trials show promise in increasing the probability of long-term survival, ICIs can cause significant side effects, including dangerous endocrinopathies. 

“One serious disruption to the endocrine system is insulin-deficient diabetes, which is essentially ICI-induced Type 1 diabetes,” says Alina Galant, PharmD, a Medical Oncology Clinical Pharmacy Specialist at University Hospitals Seidman Cancer Center. “Although extremely rare, these side effects can happen at the first dose or months into therapy and can be rapid and severe at onset.” Symptoms, including diabetic ketoacidosis, can be life-threatening and require hospital admission and treatment with insulin therapy. 

Patients treated at the UH Seidman Cancer Center are carefully monitored for adverse side effects and counseled on symptom monitoring. “All of our oncologists are very much aware of these rare inflammatory responses and work to catch symptoms before they progress in severity,” Dr. Galant says. “We also have an outstanding endocrinology team at University Hospitals that follows patients who develop insulin sensitivity.” 

When metabolic complications related to cancer treatment do occur, diabetes educators provide bedside support and training to help patients administer insulin and develop an understanding of how to utilize diabetes devices and supplies. This helps ensure individuals and family members feel able to manage glucose levels outside the controlled environment of the hospital. Coordinated discharge planning helps patients receive continuation of care in the outpatient setting. 

Most of the time, ICI-induced Type 1 DM is not reversible and requires lifelong insulin therapy. “For patients who previously did not have diabetes or maybe had Type 2 and are now completely insulin deficient, it can be an overwhelming life change,” Dr. Tranchito says. “Fortunately, we can connect patients to diabetes tools and technology that can help them adapt to their new normal and keep their blood glucose within safe and comfortable levels.”

For more information about the endocrine side effects of cancer treatment in Type 1 diabetes, please contact the UH Diabetes and Metabolic Care Center at 216-286-8988.

Contributing Experts:
Lily Tranchito, DO
Endocrinologist
University Hospitals Diabetes and Metabolic Care Center
University Hospitals Cleveland Medical Center

Alina Galant, PharmD
Medical Oncology Clinical Pharmacy Specialist
University Hospitals Seidman Cancer Center