Glycemic Management in Patients with Cancer: Balancing Active Control and Palliative Care

Cancer and diabetes frequently coexist, and glycemic management in patients with cancer should be individualized according to prognosis, treatment intent, and clinical context. In long-term cancer survivors, active glycemic control may contribute to metabolic health, cardiovascular risk reduction, and preservation of quality of life, although evidence directly linking improved glycemic control to better cancer outcomes remains largely observational. During chemotherapy, glucose levels may fluctuate substantially because of glucocorticoids, immune checkpoint inhibitors, PI3K/mTOR inhibitors, nutritional changes, infection, and organ dysfunction. Management should therefore focus on preventing severe hyperglycemia, diabetic ketoacidosis, hyperosmolar hyperglycemic state, treatment delays, and hypoglycemia, while selecting glucose-lowering agents according to the mechanism of cancer therapy-related hyperglycemia and patient safety. In patients with advanced cancer or those receiving end-of-life care, glycemic targets should shift from strict target-based control to symptom relief, avoidance of hypoglycemia, reduction of treatment burden, and preservation of comfort. Overall, glycemic management in patients with cancer requires a flexible strategy that continually recalibrates the balance between active control and palliative care according to changing clinical circumstances.