Aims: Survivors of breast cancer have increased rates of obesity, diabetes, cardiovascular disease and fractures. The mechanisms underlying these associations are not fully clarified. The aim of this study was to determine the natural history of changes in metabolic, cardiovascular and bone health in women treated with chemotherapy for early stage breast cancer.
Methods: Sixteen women with early breast cancer and 17 controls were studied. Twelve patients returned for a second visit 7±1 months later following cancer treatment (chemotherapy only (n=2), chemotherapy and radiotherapy (n=10)). Glucose and lipids were measured on a fasting blood sample. Reactive hyperaemia index (RHI) was measured by peripheral arterial tonometry to estimate endothelial function, pulse wave velocity (PWV) by applanation tonometry to quantify arterial stiffness and spontaneous baroreceptor sensitivity (BRS) was calculated by the sequence method to measure autonomic nervous system activity. Resting energy expenditure (REE) was assessed by indirect calorimetry and body composition by dual energy X-ray absorptiometry.
Results: There were no significant differences in age (53±9 vs 54±11 years, p=0.82) or body mass index (28±7 vs 28±6, p=0.97) between patients and controls. Patients had higher triglycerides (1.2±0.1 vs 0.8±0.1 mmol/L, p=0.03) and a lower BRS that approached statistical significance (13.4±1.5 vs 17.4±1.6 ms/mmHg, p=0.08). There were no significant differences in fasting glucose, RHI, PWV, REE or body composition between patients and controls. Following cancer treatment there was a fall in bone mass (2.27±0.11 vs 2.20±0.10 kg, p=0.03), but no significant change in other cardiovascular and metabolic measurements.
Conclusions: Patients with breast cancer have higher triglycerides and autonomic dysfunction before cancer treatment, which may contribute to risk of cardiovascular disease. Cancer treatment resulted in a clinically significant fall in bone mass, which is likely to increase fracture risk, but no further perturbations in cardiovascular risk markers.
Supported by Flinders Medical Centre Foundation Grant.