Monthly injectable steroid contraceptives and cervical carcinoma

The World Health Organization Collaborative Study of Neoplasia and Steroid Contraceptives is a large multinational hospital-based case-control study of steroid contraceptives and gynecologic, hepatobiliary, and mammary neoplasms. Monthly injectable steroid contraceptives which contained the long-acting progestogen dihydroxyprogesterone acetofenide plus a shorter-acting estrogen (usually estradiol enanthate) were used by women in two of the countries (Chile and Mexico) from which data were collected. In preliminary analyses of data from Chile (1979-1983), a strong association was observed between use of these products and invasive cervical Cancer. Therefore, three additional data sets from these two countries were analyzed in further detail for this report. Analyses of additional data from Chile on invasive cervical Cancer (1983-1985) and cervical carcinoma in situ (1979-1986) and of data on invasive cervical Cancer from Mexico (1979-1986) failed to confirm the initially observed association. The original finding was probably due to chance, but a causal interpretation cannot be confidently ruled out, and additional studies are warranted.