A case-control study of cancer of endometrium in Athens.

Eighty-three women with invasive adenocarcinoma of the endometrium and 164 control women hospitalized for various orthopedic conditions were interviewed regarding demographic, reproductive, socio-economic and biomedical characteristics, including their use of tobacco, drugs and exogenous estrogens. The data were analyzed by modelling rate ratio (r) through multiple logistic regression. The main results were as follows: women with invasive adenocarcinoma of the endometrium had earlier menarche (r = 0.82 for every additional year; one-tailed p approx. 0.04), later menopause (r = 1.50 for a 5-year difference; one-tailed p approx. 0.004), and fewer live-born children (r = 0.86 for every additional child; one-tailed p approx. 0.08); they were also taller (r = 1.33 for a 5-cm difference; one-tailed p approx 0.03), whereas weight, adjusted for height, was not a statistically significant risk indicator (one-tailed p approx. 0.38). Regular use of combination oral contraceptives was associated with a reduced risk of endometrial cancer (r = 0.56), whereas intake of menopausal estrogens for more than 6 months was associated with an increased risk (r = 2.04); however, because of the low frequency of use of exogenous estrogen preparations in Greece, neither of these 2 results was statistically significant. Tobacco smoking was associated with a significantly reduced risk of endometrial cancer; smoking 15-20 cigarettes per day for 20 years was associated with a rate ratio of 0.49 (one-tailed p approx. 0.03). The protective effect of tobacco smoking was evident only among post-menopausal women. These results indicate that the risk profile of endometrial cancer is similar in high-risk and low-risk countries, and underline the importance of unopposed estrogenic stimulation in the pathogenesis of this cancer.