The Pill & Breast Cancer ... PSA

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The correlation between oral contraceptives and an increased risk in breast cancer is an area of concern to me. I have two young adult daughters...18 and 21 years.

I myself was put on oral contraceptives when I was 16 years old and attending a co-ed boarding school. It was the school administration's way of combating scandal. During this chapter in my life (more like novella...) I discovered the hypothesis that the ingestion of oral contraceptives before age 20 may play into a women's increased likelihood of developing breast cancer later in adulthood. As with all of the "science" in the area of medicine and disease, it is another theory -- one with probably merit. There is always a consequence / impact / alteration when we introduce an agent (whether it be foreign or an amplification of one already naturally occurring)  into our body chemistry. I am always leery, however, to accept such theories and studies. When it comes to medical theories and the funded study thereof, my first question is: "who underwrote the study, and what was their motivation (the "who" usually answers the latter query).

How do oral contraceptives affect breast cancer risk?



A woman’s risk of developing breast cancer depends on several factors, some of which are related to her natural hormones. Hormonal factors that increase the risk of breast cancer include conditions that may allow high levels of hormones to persist for long periods of time, such as beginning menstruation at an early age (before age 12), experiencing menopause at a late age (after age 55), having a first child after age 30, and not having children at all.


A 1996 analysis of worldwide epidemiologic data conducted by the Collaborative Group on Hormonal Factors in Breast Cancer found that women who were current or recent users of birth control pills had a slightly elevated risk of developing breast cancer. The risk was highest for women who started using OCs as teenagers. However, 10 or more years after women stopped using OCs, their risk of developing breast cancer returned to the same level as if they had never used birth control pills, regardless of family history of breast cancer, reproductive history, geographic area of residence, ethnic background, differences in study design, dose and type of hormone, or duration of use. In addition, breast cancers diagnosed in women after 10 or more years of not using OCs were less advanced than breast cancers diagnosed in women who had never used OCs. To conduct this analysis, the researchers examined the results of 54 studies. The analysis involved 53,297 women with breast cancer and 100,239 women without breast cancer. More than 200 researchers participated in this combined analysis of their original studies, which represented about 90 percent of the epidemiological studies throughout the world that had investigated the possible relationship between OCs and breast cancer (2).


The findings of the Women’s Contraceptive and Reproductive Experiences (Women’s CARE) study were in contrast to those described above. The Women’s CARE study examined the use of OCs as a risk factor for breast cancer in women ages 35 to 64. Researchers interviewed 4,575 women who were diagnosed with breast cancer between 1994 and 1998, and 4,682 women who did not have breast cancer. Investigators collected detailed information about the participants’ use of OCs, reproductive history, health, and family history. The results, which were published in 2002, indicated that current or former use of OCs did not significantly increase the risk of breast cancer. The findings were similar for white and black women. Factors such as longer periods of use, higher doses of estrogen, initiation of OC use before age 20, and OC use by women with a family history of breast cancer were not associated with an increased risk of the disease (3).


In a National Cancer Institute (NCI)-sponsored study published in 2003, researchers examined risk factors for breast cancer among women ages 20 to 34 compared with women ages 35 to 54. Women diagnosed with breast cancer were asked whether they had used OCs for more than 6 months before diagnosis and, if so, whether the most recent use had been within 5 years, 5 to 10 years, or more than 10 years. The results indicated that the risk was highest for women who used OCs within 5 years prior to diagnosis, particularly in the younger group (4).


Selected References


1. Burkman R, Schlesselman JJ, Zieman M. Safety concerns and health benefits associated with oral contraception. American Journal of Obstetrics and Gynecology 2004; 190(4 Suppl):S5–22.


2. Collaborative Group on Hormonal Factors in Breast Cancer. Breast cancer and hormonal contraceptives: Collaborative reanalysis of individual data on 53,297 women with breast cancer and 100,239 women without breast cancer from 54 epidemiological studies. Lancet 1996; 347:1713–1727.


3. Marchbanks PA, McDonald JA, Wilson HG, et al. Oral contraceptives and the risk of breast cancer. New England Journal of Medicine 2002; 346(26):2025–2032.


4. Althuis MD, Brogan DD, Coates RJ, et al. Breast cancers among very young premenopausal women (United States). Cancer Causes and Control 2003; 14(2):151–160.