[Cancer risk under hormone therapy]

Estrogens are not carcinogenic. They create however a milieu, which generally stimulates cell division and growth of the target organs, also in cases of existing early neoplastic changes. This growth stimulating effect is dependent on dose and duration of the estrogen effects. Low doses exert no significant influence, medium doses are stimulating, high doses inhibit carcinoma growth, if the tumor is hormone responsive. Cyclic application of a progestogen stops proliferation and induces the specific function of the target tissue. This influence is mediated through a reduction of the number of estrogen receptors, a stimulation of the transformation of estradiol to estrone, a decrease of intracellular metabolism and a reduction of blood perfusion of the target organs. Progestogens therefore act generally preventive against cancer development at the genital organs and probably also on the breast. They should therefore principally be given together with estrogens for at least 10, optimal 12 to 14 days at month. Whether the compromise to give a progestogen only every three or six month will be acting equally carcinoma preventive as the monthly medication, ist not known. In woman bearing risk factors - except proliferative mastopathy - an estrogen-progestogen substitution seems not to increase the inherent risk, rather to reduce it. However nevertheless the manifestation of genital and breast cancer occurs preponderately in women at risk. Familial-genetic immunologic, metabolic factors, weight, race, nutrition, chronic inflammation, regeneration, old age and other risks seem equally or even more important than hormonal factors. Women, who receive a long time estrogen-progestogen substitution, have a lower risk to develop endometrial and ovarian cancer. This is probably also true for mammary and colon cancer. Meta-analyses of all studies could not show so far an increased risk for mammary cancer in estrogen-progestogen substituted postmenopausal women. Women, who receive a postmenopausal long during estrogen-progestogen substitution show statistically a better prognosis of their genital and mammary cancers, if they occur, than unsubstituted controls. Following treated cervical, endometrial and ovarian cancer a strictly indicated estrogen-progestogen substitution is possible without causing drawbacks. The so far valid contraindication against estrogens in post-carcinoma patients does not longer exist. Positive influences on cure rates and survival have been described. In cases of estrogen-progestogen negative receptor mammary cancer cases a substitution is also possible. In all other cases hormones can be given after five years recidive free survival. It is recommended to prescribe not too high doses of estrogens and to combine them with an effective progestogen.(ABSTRACT TRUNCATED AT 400 WORDS)