[Precancerous states of the endometrium: hormonal aspects]

The two types of endometrial carcinomas are preceded by precancerous lesions. Type I endometrial carcinomas are most commonly encountered in perimenopausal women with the classical risk factors associated with estrogen exposure: obesity, multiparity, diabetes, estrogen treatment, ... Hyperplasia (simple, followed by complex forms without cellular atypias and subsequently by complex hyperplasias with cellular transformation) precede such cancers. Estrogens exert a promoting effect on these lesions but do not initiate them. Progesterone and progestins exert a preventive and protective effect. However, the progressive loss of steroidal receptors is correlated to the progression of tissular anomalies and to the onset of cytogenetic anomalies and to mutations of p53 anti-oncogene. The preventive role of progestin is well established, but their curative beneficial effect on atypical precursors forms of endometrial cancers and on endometrial carcinomas remains controversial. The second type of endometrial cancer appears during the postmenopause and is characterized by an increased invasiveness and a poor prognosis, devoid of identifiable risks factors, these aggressive cancers are not preceded by hormone-sensitive precancerous lesions, but by an intra-epithelial endometrial carcinoma. This lesion appears most often in an atrophic endometrium. Finally, the two types of precancerous states are characterized by distinct gene anomalies suggesting two different pathogenic mechanisms of cancerisation.