Progesterone and breast cancer

In occidental countries the carcinoma of the mammella has an incidence of 45 cases on 1000 women. Several clinical and epidemiological evidences demonstrate that all the conditions of iperestrogenism and extended exposure to estrogens are associated to an increased incidence of mammary malignant epitelial tumor. The relationship between the exposure to ovarian hormones and the mammary neoplasia has created doubts about using the substitutive hormonal therapy in menopause. Through an analysis of the recent literature our work aims to evaluate the action of the progesterone on the mammella and, in particular, to study its effects on the cells of the mammary gland in association to estrogens during hormonal replacement therapy in menopause.