Dietary factors and breast cancer

Population and case-control studies indicate the involvement of diet in breast cancer aetiology. Obesity appears to be a risk factor for postmenopausal disease, and most likely operates through the modification of oestrogen synthesis and metabolism. Dietary fat, though a major source of calories and, therefore, a contributor to the development of obesity, may have a more specific role, involving oestrogens, protein hormones and growth factors, or other, non-endocrine, mechanisms. Obesity also has an adverse effect on breast cancer prognosis after surgery. Again, this may, at least partially, involve enhanced oestrogenic stimulation of residual tumours in postmenopausal patients. Though knowledge of these relationships can be expanded by the application of appropriate animal models, the final test has to be the implementation of carefully designed intervention trials in groups of women at high risk of breast cancer, and as an adjunct to surgery in breast cancer patients.