Add-On Treatment with Gliclazide for Cancer Patients with Type 2 Diabetes Undergoing Cyclic Glucocorticoid-Containing Chemotherapy

<b>Aims</b>: Despite its high prevalence, studies on glucocorticoid-induced hyperglycemia are lacking. We examined the glucose profiles of patients with type 2 diabetes undergoing dexamethasone-containing chemotherapy using continuous glucose monitoring (CGM). We also investigated the effects of gliclazide on the management of hyperglycemia in these patients. <b>Materials and Methods</b>: Seventeen patients with type 2 diabetes who received cyclic chemotherapy with dexamethasone were enrolled in this study. During the first cycle, iPro2, a blinded CGM device, was applied for 7 days. If a patient's CGM data exhibited an increase of 20% or more in the mean glucose level after dexamethasone administration, they received the second cycle, unless they had already received sulfonylurea or their chemotherapy regimen had changed. During the second cycle, the patients were treated with gliclazide as an add-on to their routine diabetic medication. <b>Results</b>: Dexamethasone treatment significantly increased glucose levels, especially in patients with a longer diabetes duration (8.4 years vs. 1.2 years, <i>p</i> = 0.009). For the nine patients who proceeded to the second cycle, gliclazide treatment significantly ameliorated hyperglycemia. Time in range increased from 33.11% to 45.22% (<i>p</i> = 0.020), and time above range significantly decreased from 66.89% to 52.78% (<i>p</i> = 0.003). The glucose management indicators were 9.52% and 8.40% for pre- and post-gliclazide treatment, respectively. One patient visited the emergency department because of symptomatic hypoglycemia. <b>Conclusions</b>: Chemotherapy regimens containing dexamethasone result in high blood glucose levels even after the last dexamethasone dose in patients with pre-existing diabetes. Adding gliclazide could be beneficial in managing hyperglycemia during dexamethasone-containing chemotherapy.