Insulin glargine versus other types of basal insulin–clinical and tumor characteristics in patients with breast carcinoma

BACKGROUND: Recent epidemiological studies have suggested that some insulin analogues could be associated with an increased risk of cancer. The aim of this retrospective study was to examine whether patients with diabetes mellitus (DM) using insulin glargine have a higher tumor stage of breast carcinoma in comparison to patients using other types of insulin. METHODS: We performed a chart review of 79 surgically treated breast carcinoma patients (mean age of 66.5 years; range 38-86 years) who were on insulin. Insulin glargine was used in 13 patients, while the other 66 patients were on other types of insulin. Clinical and histopathology characteristics of patients on glargine versus other types of insulin were compared using a chi-square test and non-parametric statistical analysis. RESULTS: DM type 1 and DM type 2 was present in 14 and 65 patients, respectively. The mean tumor size was 2.98 cm. The TNM tumor stage at diagnosis was not higher among patients on glargine compared to patients on other types of insulin (T1/T2 85% vs. 68%, T3/T4 15% vs. 32%, p = 0.32; N1 54% vs. 58%, p = 0.80; M1 8% vs. 6%, respectively). No significant differences between both study groups (glargine vs. other types of insulin) were found in the ages of the patients, their BMI, tumor histology, grade, number of metastatic lymph nodes, hormone receptors or HER-2 status. CONCLUSION: We could not show that patients with DM using insulin glargine have a higher tumor stage of breast carcinoma in comparison to those using other types of insulin.