Birth Control Pills & Breast Cancer?

We have more data now on the ongoing body of work on whether the synthetic hormones in birth control pills cause breast cancer. You'll notice in my other blog a recent study showing an increased risk (http://menopause.zaadz.com/blog/2006/12/the_pill_linked_to_premenopausal_breast_cancer). In the spirit of unbiased opinion -- here is a recent study showing no increased risk, although remember that The Pill is proven to lessen libido.

Do Oral Contraceptives Affect Risk for Death from Breast Cancer?

OC use had neither a beneficial nor a harmful effect on breast cancer mortality.

The relation between oral contraceptive (OC) use and breast cancer risk remains under constant surveillance. To study the effects of OC use on risk for death from breast cancer, investigators analyzed cancer registry data from the Surveillance, Epidemiology, and End Results Program in conjunction with linked data from the population-based, case-control Cancer and Steroid Hormone (CASH) study. Fifteen-year survival was assessed in 4292 women who had been diagnosed with breast cancer and who were interviewed about reproductive contraceptive and disease history, family history, and personal characteristics and behaviors during the CASH study (conducted from 1980 through 1982).

During the 15-year follow-up, 1473 of the women died from breast cancer; 80% survived for 5 years, 70% for 10 years, and 64% for 15 years. Compared with women who had never used OCs, the relative risk for death from breast cancer in ever-users was less than 1.0 (adjusted hazard ratio, 0.94; 95% confidence interval, 0.83–1.06). Neither duration of use nor age at first use affected the risk for death from breast cancer. Adjusted analysis showed that stage of disease at diagnosis did not affect the relation between breast cancer mortality and time since first and last use of OCs. Women who were currently using OCs at diagnosis had a statistically insignificant adjusted HR of 0.90.

Comment: These researchers did not address the association between oral contraceptive use and breast cancer diagnosis but rather the effect of OCs on breast cancer mortality. One limitation of the study is that it did not take into account estrogen- or progesterone-receptor status or the presence of BRCA mutations or HER2/neu _expression. Nonetheless, these results provide reassurance that prior use of OCs is not associated with increased mortality from breast cancer.

— Sandra Ann Carson, MD
Published in Journal Watch Women's Health November 15, 2007

Citation(s):

Wingo PA et al. Oral contraceptives and the risk of death from breast cancer. Obstet Gynecol 2007 Oct; 110:793.

Original article (Subscription may be required)
Medline abstract (Free)