Glucocorticoids, which are administered with chemotherapy, cause hyperglycemia. Glycemic variability among breast cancer patients without diabetes is not well known. A retrospective cohort study was conducted involving early-stage breast cancer patients without diabetes who received dexamethasone prior to neoadjuvant or adjuvant taxane chemotherapy between August 2017–December 2019. Random blood glucose levels were analyzed, and steroid-induced hyperglycemia (SIH) was defined as a random glucose level of >140 mg/dL. A multivariate proportional hazards model was used to identify the risk factors of SIH. Out of 100 patients, the median age was 53 years (IQR: 45–63.5). A total of 45% of patients were non-Hispanic White, 28% Hispanic, 19% Asian, and 5% African American. The incidence of SIH was 67%, and glycemic fluctuations were highest in those with glucose levels of >200 mg/dL. Non-Hispanic White patients represented a significant predictor for time to SIH, with a hazard ratio of 2.5 (95% CI: 1.04, 5.95, p = 0.039). SIH was transient in over 90% of the patients, and only seven patients remained hyperglycemic after glucocorticoid and chemotherapy completion. Pretaxane dexamethasone-induced hyperglycemia was observed in 67% of the patients, with the greatest glycemic lability in those patients with blood glucose levels of >200 mg/dL. The non-Hispanic White patients had a higher risk of developing SIH.

Purpose: Glucocorticoids administered with chemotherapy cause hyperglycemia even in the non-diabetes setting. The prevalence of hyperglycemia and glycemic variability among breast cancer patients without diabetes are not well known, especially across different race/ethnicities. Methods: A retrospective cohort study was conducted involving early-stage breast cancer patients without diabetes who have received dexamethasone prior to (neo) taxane adjuvant chemotherapy between August 2017-December 2019. Random blood glucose levels were extracted, and steroid-induced hyperglycemia (SIH) was defined as a random glucose level of >140 mg/dL. Multivariate proportional hazards model was used to identify risk factors for SIH.Results: Of 100 total patients, the median age was 53 years (IQR: 45-63.5). Forty-five percent were non-Hispanic white, 28% Hispanic, 19% Asian, and 5% African American. The incidence of SIH was 67%, and glycemic fluctuations were highest in those with glucose levels >200 mg/dL. Non-Hispanic white remained as a significant predictor for time to SIH with a hazard ratio of 2.5 (95% CI: 1.04, 5.95, p=0.039). SIH was transient in over 90% patients, and only 7 patients remained hyperglycemic after glucocorticoid and chemotherapy completion.Conclusions: Pre-taxane dexamethasone-induced hyperglycemia in 67% of patients with the greatest glycemic lability in women with blood glucose level > 200 mg/dL. Non-Hispanic white had a higher risk of developing SIH. SIH patients should be monitored using a continuous glucose monitoring or self-monitoring of blood glucose devices. Diagnostic tests for diabetes such as HbA1c, oral glucose tolerance test, fasting plasma glucose, and endocrinology consultation should also be recommended.