Effects of Adjuvant Chemotherapy on Insulin Resistance in Patients with Early Breast Cancer

Objective: To assess the effect of adjuvant chemotherapy on insulin resistance in patients with early breast cancer.
Material and Methods: Twenty-three non-diabetic patients were included. Patients were prospectively evaluated before, during, and after chemotherapy. Demographic, anthropometric, histopathological features, and treatment data were recorded. Blood samples were taken to evaluate fasting blood glucose, fasting insulin levels, and HbA1c. Homeostatic model assessment for insulin resistance (HOMA-IR) score measured using fasting blood glucose and fasting insulin levels.
Results: Overall, pre- and post-chemotherapy mean weights were comparable (70.17 kg vs. 71.43). Prechemotherapy mean HOMA-IR was 4.99 and significantly higher than the control group of the healthy population (p=0.008). The mean values of the HOMA-IR score before, during, and after chemotherapy were 4.99, 3.47, and 3.13, respectively. Although the mean HOMA-IR decreased after chemotherapy, these decreases were not statistically significant (p=0.089). The mean fasting glucose levels before, during, and after chemotherapy were 95.5, 101.9, and 94.1 mg/dL, respectively. Before, during, and after chemotherapy, the mean fasting insulin levels were 21.43, 13.32, and 13.28 μIU/mL, respectively.
Conclusion: In the study, we observed a higher rate of insulin resistance in patients with breast cancer. The mean values of the HOMA-IR score decreased during and after chemotherapy.