Estrogen and Progestin Potency of Oral Contraceptives and Ovarian Carcinoma Risk

Comment regarding the paper: Lurie G, Thompson P, McDuffie KE, Carney ME, Terada KY, and Goodman MT. The Association of Estrogen and Progestin Potency of Oral Contraceptives with Ovarian Carcinoma Risk. Obstet Gynecol 2007 March; 109:597-607

The majority of epidemiological studies demonstrate that use of oral contraceptives decreases the risk of epithelial ovarian carcinoma. However, there is no consensus regarding the effect of dose of estrogen and progestin components on risk. 

In our population-based case-control study, we showed that oral contraceptives with low potency of estrogen and progestin components were at least as effective in reducing ovarian cancer risk as high potency formulations. 

This study is unique in that a relatively large subset of women exclusively used oral contraceptive pills with norethindrone with no intra-individual variation in its dose. Among these women, using low doses of norethindrone was associated with significantly lower odds of developing ovarian carcinoma as compared to using high-dose norethindrone formulations (adjusted for estrogen dose). 

The fact that these low potency oral contraceptives reduce the risk of ovarian cancer is reassuring considering the present-day tendency to prescribe low-dose oral contraceptives. Future studies that include larger numbers of women are needed to further evaluate the association of low dose oral contraceptive formulations with ovarian cancer risk.

Galina Lurie

Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI, USA