Factors associated with non-epithelial ovarian cancer among Mexican women: a matched case-control study

The purpose of this study was to identify risk factors associated with the development of non-epithelial ovarian cancer in Mexican women. A case-control study was carried out on women registered with the Mexican Institute of Social Security in Mexico City over a period of two years (1995-97). Twenty-eight new cases were recruited from the Gynecology and Obstetrics Hospital no. 4, "Luis Castelazo Ayala", and were matched by age with 84 controls selected randomly. Eighteen (64.3%) cases of germ cell tumors and 10 (35.7%) stromal sex cord tumors were found. The number of full term pregnancies was associated inversely to development of stromal sex cord tumors with lower risk in women with more than three full term pregnancies (odds ratio, 0.02: 95% confidence interval, 0.001-0.56) compared to nulliparous women. No associations were found respecting to germ cell tumors. Parity was inversely associated to development of stromal sex cord tumors, probably as a result of the endocrine system's influence on the ovaries. The development of germ cell tumors could be associated to factors not evaluated in this study.