[Etiology of endometrial cancer].

Based on a survey of the literature, a summary of the etiology of endometrial cancer (EC) is presented. The effect of a number of expositions on the risk of developing EC, expressed as odds ratio or relative risk, are indicated. Combining these with the prevalence of the specific exposition allows calculation of the etiologic fraction (EF) for each risk factor. The etiologic fraction indicates the proportion of EC that would disappear if the exposition were eliminated. Obesity increases the risk of EC with a factor three to four. One quarter of Danish women of 60-70 years of age have a relative weight exceeding 1.2 times the ideal weight. The corresponding EF is 41%. Oestrogen substitution therapy is connected with an odds ratio of EC of 3.8 and an EF of 8%, anticipating that the lifetime prevalence of pure oestrogen substitution is 3%. On the other hand, oral contraceptives imply a reduction in EC of 14%, parity of 37% and cigarette smoking of 26%. It appears that the etiology of EC is multifactorial, and that a number of disposing and protecting factors are identified and quantified. The greatest prophylactic potential seems to be in reducing weight among obese women.