Chemotherapy uses anti-cancer drugs that often have systemic effects throughout the body. Certain agents and frequently co-administered medications can significantly disrupt the body’s glucose regulation, leading to hyperglycemia. Understanding this metabolic side effect is necessary for managing cancer treatment and maintaining overall health during therapy.
How Chemotherapy Affects Glucose Metabolism
Chemotherapy and supportive medications can cause an imbalance in glucose processing through several distinct physiological pathways. One common mechanism is the induction of insulin resistance, where the body’s cells become less responsive to insulin. Since insulin moves glucose out of the bloodstream, resistance effectively leaves glucose trapped in the blood.
Treatment can also directly impact the pancreas, the organ responsible for producing insulin. Some drugs are toxic to the pancreatic beta cells, reducing the total amount of insulin available to regulate blood sugar. Furthermore, the physical and emotional stress of cancer treatment triggers the release of counter-regulatory hormones like cortisol. These stress hormones oppose insulin’s action and stimulate the liver to produce more glucose, contributing to elevated blood sugar levels.
Common Chemotherapy Agents That Increase Blood Sugar
While many chemotherapy drugs can indirectly affect glucose levels, a few specific agents and drug classes have a direct impact. The most frequent cause of elevated blood sugar is the use of corticosteroids, such as dexamethasone, which are commonly given alongside chemotherapy to manage nausea or allergic reactions. These anti-inflammatory drugs increase insulin resistance and stimulate the liver to release more glucose, often leading to a temporary spike in blood sugar.
Certain cytotoxic chemotherapy agents also affect glucose control. L-asparaginase, often used in leukemias, is toxic to the insulin-producing beta cells in the pancreas, resulting in acute hyperglycemia. Additionally, some targeted therapies, specifically mammalian target of rapamycin (mTOR) inhibitors like everolimus, are associated with a high incidence of blood sugar elevation. Drugs such as 5-fluorouracil (5-FU) and certain platinum-based agents have also been linked to increased glucose levels during treatment.
Symptoms to Watch For and Management Strategies
Recognizing the signs of hyperglycemia is important for prompt management during treatment.
Symptoms of Hyperglycemia
- Increased thirst
- Frequent urination
- Persistent fatigue
- Blurred vision
- Headaches
Monitoring blood glucose is the first step. The oncology team may recommend checking levels more often, especially if the patient is taking corticosteroids or has pre-existing diabetes. The goal is often to keep blood glucose levels in a safe range, typically between 140 to 180 milligrams per deciliter, as determined by the healthcare team.
Lifestyle and Medical Interventions
Management strategies focus on lifestyle adjustments and medical intervention. Dietary changes include eating smaller, more frequent meals that balance complex carbohydrates with protein and healthy fats to prevent sharp glucose spikes. Gentle physical activity, such as walking, can help muscle cells use glucose more efficiently, but any activity should be cleared by the doctor first.
When lifestyle changes are insufficient, medical interventions are used, often involving insulin therapy to counter drug-induced insulin resistance. The type and timing of insulin or oral diabetes medications depend on the specific chemotherapy regimen and whether the patient had diabetes before treatment. All blood sugar management must be coordinated with the oncology team to ensure glucose control supports cancer therapy.
Why Controlling Blood Sugar is Critical During Cancer Treatment
Maintaining stable blood sugar levels is vital during cancer treatment. Uncontrolled hyperglycemia can negatively affect the body’s ability to recover and may reduce the effectiveness of some anti-cancer treatments. High glucose levels impair the immune system, increasing the risk of serious infections for patients already immunocompromised by chemotherapy.
Poor glycemic control contributes to increased fatigue and can impede the healing of wounds, which is relevant after surgery or port placement. Furthermore, sustained high blood sugar may worsen other chemotherapy side effects, such as nerve damage (peripheral neuropathy). Close monitoring and adherence to a tailored management plan help ensure the best possible response to therapy and a better quality of life.