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The oral contraceptive pill does not increase the risk of breast cancer
(July 2004)

In March 2002, the Women’s Lifestyle and Health Study carried out in Norway and Sweden reported a 26 percent increase in risk of breast cancer among women who had used contraceptive pills. This was in agreement with a review of 54 studies published in 1996. Those studies received a lot of publicity. Many people were convinced that long-term use of oral contraceptive pills does raise the risk of breast cancer to a moderate extent.

A leading article in The New England Journal of Medicine comes to a completely different conclusion. The multi-center study conducted around the United States compared 4,575 women ages 35 to 64 years old who had breast cancer with 4,682 controls. There was absolutely no evidence that taking oral contraceptives for any length of time increased the risk of breast cancer.

Healthful Life has never been impressed with the evidence suggesting increased breast cancer risk from use of contraceptive pills. These contradictory studies show the importance of not rushing to judgement if the various studies are not convergent or if there are just too few studies. Every time you are exposed to advertisements about health or read in newspapers, hear on radio, or see television reports of health studies, you should be skeptical. So much is inaccurate or exaggerated or preliminary data, or a single study that does not accurately reflect the overall evidence. You have to find dispassionate groups or organizations (such as Healthful Life) that will review the available data and let you know where we really stand.

It is still possible that oral contraceptive pills increase risk of breast cancer a little bit - but, probably not.

What about the use of hormones post-menopausally? These are closely related to hormones in contraceptive pills. The evidence here is better and does suggest about a 25 percent (and perhaps up to a 50 percent) increase in breast cancer for those using for at least several years. This very modest increase does not appear to be associated with an increased death rate from breast cancer; suggesting that cancers induced by hormone treatment are less severe than the usual breast cancers.