The increase in our knowledge of breast cancer risk factors and the continuing increase in incidence of breast cancer means that it is time to move from knowledge to action, says Dr Franco Berrino, head of preventive and predictive medicine at the Instituto Nazionale Tumori, Milan, Italy. He says that high levels of sex hormones and insulin-like growth factors were associated with cancer risk, and that the typical Western diet increased their biological effect.

“Breast cancer risk can be reduced by avoiding hormone replacement therapy, increasing physical activity, not being overweight, and eating a more healthy diet”, said Dr Berrino. “The problem with the diet of most people in the West is that it tends to include processed foods high in sugars and fats, too much red meat and dairy products, and not enough unrefined grains and vegetable products. This diet reduces the body’s sensitivity to insulin, and this in turn stimulates the production of sex hormones and other growth factors, which are directly linked to breast cancer risk.”

Dr Berrino is currently looking at the effect of diet and hormonal risk factors in women carrying the most common genetic mutation found in breast cancer. These women have a very high lifetime risk of developing breast cancer, and most of them develop the disease in their 30s or 40s. However, he said, it is not clear why some mutation carriers develop the disease and others do not, nor why some develop it early and some much later in life.

“Our hypothesis is that the incidence of breast cancer among mutation carriers depends on environmental factors, of which diet will be a major one,” he said.

Federation of European Cancer Societies, Mar 18, 2004