[Epidemiologic considerations on the significance of hormones in carcinogenesis].

The incidence of gynecologic malignancies shows considerable regional differences which suggest a decisive role of environmental and endocrine factors in tumor genesis. The risk of developing breast cancer increases with increasing age, a positive family history, prolonged exposure to estrogens (early menarche, late menopause), nulliparity, alcohol consumption, and obesity. A relationship between a long exposure to estrogens and an increased risk of cancer may also be assumed in the case of endometrial cancer. Whether estrogens or their metabolites promote the initiation of cancer remains to be clarified. Endocrine monotherapy with only an estrogen, obesity, nulliparity/infertility as well as a late natural menopause are well-known risk factors of developing endometrial cancer. Whereas estrogens induce a hyperplasia of the endometrial mucosa, gestagens exert a protective effect on the endometrium. Old age, a family history of breast, endometrial and ovarian cancer as well as persistent or treated infertility are the established risk factors of ovarian cancer. Each pregnancy, the intake of oral contraceptives, a hysterectomy or tubal ligation are associated with a decreased risk of developing ovarian cancer; hormonal replacement therapy has no influence on the risk of ovarian cancer.