High Blood Sugar and Lymphoma: Should You Be Concerned?

High blood sugar (hyperglycemia) can happen during lymphoma care, especially when steroid medicines like dexamethasone or prednisolone are part of treatment. This is a common and manageable issue, but it deserves attention because it can affect infection risk, energy, and how you feel day‑to‑day. ^{[1] [2]}

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Why Blood Sugar Rises During Lymphoma Treatment

• Steroids in many lymphoma regimens raise blood glucose. Dexamethasone and prednisolone reduce insulin’s effectiveness and boost liver glucose production, so sugars can spike during and shortly after dosing. Patients are often advised to monitor sugars more closely and may need diabetes medication adjustments while on steroids. ^{[1] [2]}
• Chemotherapy side effects can swing sugars. Nausea, poor appetite, or mouth sores may lead to variable intake, causing lows or highs depending on what and when you eat. Care teams commonly check blood tests to watch organ function and treatment effects, which can include glucose changes. ^{[3] [4]}
• Other cancer drugs can also elevate sugars. Some regimens require routine sugar monitoring and temporary treatment holds if levels are very high until they come down safely. Short‑term insulin or glucose‑lowering medicines may be recommended to control hyperglycemia. ^[5]

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Why It Matters

• Higher infection risk and slower healing: Elevated glucose can weaken immune defenses, which is important during chemotherapy when blood counts may already be low. Keeping sugars in a safer range helps reduce complications. ^[4]
• Hospitalization and care burden: People managing both cancer and diabetes tend to need more medical visits and may be hospitalized more often than those with cancer alone. Good coordination between oncology and primary care can lower these risks. ^{[6] [7]}
• Quality of life: Fatigue, frequent urination, and dehydration from high sugars can make treatment days harder, and severe highs can be dangerous if not addressed promptly. ^[5]

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When to Be Concerned

• Persistent fasting sugars above your usual targets or repeated random readings significantly above normal warrant a discussion with your care team. If sugars are very high, treatment may be paused until they are safely controlled, and rapid‑acting measures (like insulin) may be used. ^[5]
• Symptoms that need urgent attention: intense thirst, vomiting, confusion, fruity breath, or rapid breathing can signal diabetic ketoacidosis, which requires immediate medical care. Specialist input is recommended for severe hyperglycemia or ketoacidosis during cancer therapy. ^[5]

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Practical Steps to Stay Safe

• Monitor during steroid days: Check sugars more often on days you take dexamethasone or prednisolone and for 24–48 hours afterward. Many protocols suggest closer monitoring and adjustment of diabetes medicines while on steroids. ^{[1] [2]}
• Coordinate your care: Ask your oncologist and diabetes clinician to set a plan for glucose checks and medication adjustments during each cycle, including if an anti‑nausea NK‑1 blocker is added (it can change steroid dosing). ^[8]
• Nutrition tweaks that help: Small, regular meals with protein and fiber; limit simple sugars and juices; stay hydrated. Cancer nutrition guidance often recommends avoiding high‑sugar foods when chemo raises glucose and seeking tailored advice if control is difficult. ^{[3] [9]}
• Use the right tools: Home glucose meters or continuous glucose monitors (CGM) can help track patterns, especially around steroid dosing and chemo days. Follow device safety and calibration guidance. ^{[10] [11] [12]}
• Know your individualized targets: In cancer care, glucose and A1c goals may be personalized to balance safety and avoid hypoglycemia, particularly in older adults or those with complications. Your team may set slightly broader targets during intensive treatment to keep you safe. ^{[13] [14]}

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The Bottom Line

High blood sugar during lymphoma treatment is common, especially with steroid‑containing regimens, and it can be managed with closer monitoring, timely medication adjustments, and good care coordination. Staying ahead of sugar rises helps reduce infection risk and keeps treatment on track. ^{[1] [2] [6] [7] [5] [4] [3]}