However, the relationship between the incidence of breast cancer and unlimited consumption of alcohol was revealed. Among the factors contained in food and capable of preventing the development of breast cancer are sulfur-containing organic compounds (S-allylcysteine, present in garlic and in cruciferous plants, such as Brussels sprouts), indole-3-carbinol (also present in cruciferous), carotenoids (beta-carotene in green and yellow vegetables), vitamin E, selenium and polyphenol tea antioxidants, as well as flavonoids.
As can be assumed on the basis of recent studies, in women who lead an active lifestyle and regularly perform recreational exercise, the risk of breast cancer is reduced. However, the risk of disease among women who use hormone replacement therapy, or estrogen, or their combination with progestins, remains somewhat higher. A small incremental risk, at least in part, can be offset by more beneficial effects of hormone therapy, such as reducing the risk of osteoporosis.
Usually, 5 years after stopping the use of hormones, this effect does not appear. A recent large-scale study has demonstrated the important role of breastfeeding in preventing breast cancer. A clear relationship has been traced between the length of the breastfeeding period and the risk of developing the disease. The relative decrease in the incidence rate reaches 4.3% for each year of breastfeeding, and with the birth of each new baby, the incidence decreases by another 12%. These conclusions remain fair for women living in both developed and developing countries, do not depend on their age and menopausal age, on the membership of women in a particular ethnic group, on the age of their first pregnancy, and on the total number of children born.
As the authors of the study showed, the cumulative incidence of breast cancer in developed countries could be reduced more than twice (from 6.3 to 2.7 per 100 women of 70 years of age) if a woman had at least 2-3 children , and throughout the childbearing period breastfed them. Until recently, it was common among women in developing countries. According to the authors, breastfeeding provides nearly two-thirds of the overall reduction in the incidence of breast cancer.
In general, there is currently a decrease in mortality from breast cancer. This is probably due to the improvement of methods for early diagnosis and treatment, as well as the introduction of the National Screening Research Program in the UK. As recent studies have shown, taking aspirin reduces the risk of breast cancer. So with the daily intake of this drug, the risk is reduced by 28% – with a probability of a successful outcome of 0.72, and the effect is more pronounced in women in the postmenopausal period.
The identification and cloning of the BRCA1 and BRCA2 genes made it possible to understand the molecular basis of the origin of familial breast cancer. The presence of mutations in these genes causes a lifelong 50–85% chance of developing breast cancer, usually in the postmenopausal period. In this case, the risk of developing ovarian cancer is 15-45%. However, a large number of cases of sporadic cancer are not associated with the BRCA1 and BRCA2 genes, and other genes are also known that also determine the susceptibility to this disease, for example, the gene encoding the p53 protein. Women who have a mutant gene for ataxia, teleangiectasia, are also at increased risk. The BRCA1 gene consists of 5711 base pairs and occupies about 100 kbaz.