[Hormone and breast cancer].

Most of breast cancers are hormonedependent. Hormone treatment (contraception and menopause hormone treatment) has a promoter effect on preexisting lesions: the increase in risk decreases after stopping treatment. Hormonal contraception increases modestly the risk in current users but the amplitude of the risk remains low up to 40 years when this increase is more significant due of the number of breast cancer occurring at that age. Pregnancy decreases the risk if at a young age but after 25 years may increase the risk. Combined menopause hormone treatment is associated to a greater risk than estrogens alone. Breast cancer associated with hormone treatment is estradiol receptor positive. There is an increase in the risk with duration. Combining the hormone treatment with an anti-estrogen could decrease the risk of breast cancer and help to keep the benefits of estrogens.