Diabetes, Obesity, and the Risk of Breast Cancer: An Attempt to Decipher the Interconnections

Diabetes and obesity are linked to a higher risk of breast and other cancers. In addition to the direct effects of hyperglycaemia and insulin resistance on breast cancer cells, the complications of diabetes, obesity, and metabolic syndrome are characterised by a dysfunctional endothelium and increased inflammation in tissue phenomena that are intimately related and occur concurrently in breast cancer progression. However, the complexity of the underlying mechanisms, together with the interplay of diet and physical activity contributing to energy balance and the role of adipose tissue, hyperglycaemia, insulin resistance, and glucose intolerance, pose challenges to our understanding of the basis of this increased risk. In addition to being an established risk factor for postmenopausal breast cancer, abdominal obesity, also known as central obesity, may also raise the chance of triple-negative breast cancer, which is more common in premenopausal women. This chapter explains how various parameters like oestrogen, mammography, density, adipokines, insulin-signalling pathway activation, and inflammatory conditions, may play a part in this seemingly contradictory association. A key focus of this chapter is to better understand the impact of obesity and diabetes in the pathogenesis of breast cancer and, hence, provide some clarity into the interrelationships involved in between.

Keywords: Breast cancer, Diabetes, Hyperglycaemia, Insulin resistance, Obesity.