Fasting plasma glucose and body mass index as predictors of neoadjuvant chemotherapy response in breast cancer

Abstract

Aim: Obesity is a well-known modifiable risk factor for breast cancer. Impaired fasting glucose is a component of metabolic syndrome and a significant risk for diabetes. We aimed to research the effect of these two major components of metabolic syndrome on neoadjuvant chemotherapy (NAC) response in breast cancer. Methods: We conducted 161 patients who had received NAC from January 2016 to January 2022. Fasting plasma glucose levels were measured at least two times and BMI was recorded before starting NAC. Impaired fasting glucose is defined as plasma glucose levels of 100 to 125 mg per dL. Analyses were compared into two groups according to FPG levels below or above 100 mg/dl and according to BMI obese (BMI30? kg/m2), or non-obese (BMI <30 kg/m2). The pathologic response was evaluated, and patients were divided into five groups according to the Miller-Payne grading system classified from grade V to I, complete pathologic response, loss of more than 90% of tumor cells, reduced 30% and 90% of tumor cells, lost less than 30% of tumor cells, and had no reduction in cellularity and no change malignant cells respectively Results: In the pathologic responses, 70.8% of patients with impaired fasting glucose levels were grade 1 non-reduction with NAC. Disease free-survival was shorter in the group that had impaired fasting glucose than in the group that had normal fasting plasma glucose (FPG) (p=0.031). In univariate analysis clinical stage 3 (p <0.001), postmenopausal status (p=0.037), human epidermal growth factor receptor 2 (HER-2) negativity (p<0.001), estrogen receptor (ER) positivity (p <0.001), progesterone receptor (PR) positivity (p <0.001) rate were higher in grade 1 unresponsive patients compared to patients with pathological response grade 2, grade 3 and grade 4. In multivariate analysis showed that fasting plasma glucose, clinical stage, HER-2 status, and ER status were independent predictor factors for pathological complete response (pCR). BMI had no impact on pCR. Our trial showed that the ratio of pCR in patients with impaired fasting glucose was 2.5 times lower than that in patients who had normal FPG levels [HR: 2.5, 95%CI 1.08–5.92, p = 0.03]. Conclusion: Fasting plasma glucose significantly impacted both pCR and recurrence.