Prior oral contraceptive use is associated with premenopausal breast cancer

In our meta-analysis, we examined pre-menopausal women in all case-control retrospective studies (published after 1980).  We concluded that 21 out of 23 of these studied showed a positive risk for pre-menopausal women who took (or are taking) oral contraceptives prior to their first term pregnancy.  The cumulative risk for this group of women was an increased risk of developing breast cancer of 44%, which was significant at the 99% confidence interval ((OR, 1.44; 99% CI 1.24-1.68).

This is a very important finding and supports the World Health Organization’s recent classification of oral contraceptives as a Class One Carcinogen (2005).

Bibliographic reference:

Kahlenborn C, Modugno FM, Potter DM, Severs WB. Oral contraceptive use as a risk factor for premenopausal breast cancer: a meta-analysis. Mayo Clin Proc 2006; 81(10):1290-1302

Chris Kahlenborn

Department of Internal Medicine, Altoona Hospital, Altoona, PA, USA