Insulin sensitivity, cardiovascular function and bone health in women with early stage breast cancer before and after cancer treatment

Abstract

Background: Cardiovascular disease is a leading cause of death in breast cancer survivors, but the underlying cause is not fully characterised.Aims: To determine whether insulin sensitivity, cardiovascular risk markers and body composition were perturbed in women treated with chemotherapy for early stage breast cancer and whether perturbations occurred before or after cancer treatment.Methods: Sixteen women with breast cancer and 17 control subjects were studied.Twelve breast cancer patients returned for a second visit following cancer treatment comprising chemotherapy (n = 2), or chemotherapy and radiotherapy (n = 10). The Matsuda index to estimate insulin sensitivity, fasting lipids, pulse wave velocity (PWV), reactive hyperaemia index (RHI) and body composition by dual energy X-ray absorptiometry were measured.Results: There were no significant differences in age (53 AE 9 vs 54 AE 11 years; P = 0.82) or body mass index (28 AE 7 vs 28 AE 6; P = 0.97) between patients with breast cancer and controls. Patients with breast cancer had higher triglycerides than controls (1.2 AE 0.1 vs 0.8 AE 0.1 mmol/L; P = 0.03), but there were no significant differences in the Matsuda index, PWV and RHI. Following cancer treatment, there was a lower Matsuda index (6.3 AE 1.2 vs 5.2 AE 1.0; P = 0.01), but this was not associated with a significant change in vascular function. Bone mass fell by 3% from 2.27 AE 0.11 to 2.20 AE 0.10 kg after cancer treatment (P = 0.03).Conclusions: Patients with breast cancer had higher triglycerides before treatment and a reduction in insulin sensitivity and bone mass following cancer treatment. Future larger and longer-term studies should characterise the effect of reduced insulin sensitivity on rates of diabetes, cardiovascular disease, cancer outcomes and fracture.