Relationship Between Level of HbA1C and Breast Cancer Outcomes

Abstract

Diabetes and cancer are public health issues worldwide; studies have shown diabetes is related to increased breast cancer mortality. The purpose of this study was to examine associations between HbA1C and tumor stage and mortality among breast cancer patients. Data for 82 patients (36‐89 years of age) diagnosed with breast cancer were provided by the University of Arkansas for Medical Sciences (UAMS) Data Trust Warehouse. Subjects were diagnosed and treated at UAMS between 1999 ‐2009. Data included age, race, HbA1C, tumor stage, start date of service, date of last follow‐up and life/death status. Survival time was estimated from start date of service to date of last follow‐up or date of death. The Kaplan‐Meier method provided descriptive analysis of survival curves for two groups of HbA1C (HbA1C<6.5% versus HbA1C 蠅 6.5%) and two groups of BMI (BMI < 30 versus BMI 蠅 30 kg/m2); survival curves were compared using log‐rank tests. Association between HbA1C and BMI, and between HbA1C and tumor stage were determined by chi‐square. There was not a statistically significant relationship between tumor stage and HbA1C levels (x2= 0.093, p=0.47, df=1).The relationship between obesity and HbA1C was statistically significant (X2=6.13, p=0.013, df=1). Log‐rank tests determined there were not statistically significant differences between survival curves (HbA1C curves, p=0.4; BMI curves, p=0.09). There was not a statistically significant association between HbA1C and tumor stage. There may be clinically meaningful relationships based on observed trends. Future directions for research may involve exploring the role of therapeutic regimens on blood sugar levels and BMI of breast cancer patients, and their influence on breast cancer prognosis.