Oral Contraceptive-Breast Cancer Link

The Oral Contraceptive-Breast Cancer Link
by Wendy Kennedy

         The media is full right now of criticism for Catholic Church opposition to artificial contraceptive use. The Church teaches that these drugs violate the unitive and procreative nature of the sacrament of marriage, in addition to violating the sanctity of life through abortifacient actions of contraceptive hormones. Even those who do not agree with (or understand) the theological basis for Church teaching against contraception might be surprised to learn that there is firm medical evidence that supports such a stand. Research has been around for a long time pointing to a dangerous connection between oral contraceptive (OC) use and breast cancer, research that has largely been ignored by secular press. Just a quick internet search surfaced published studies pointing to such a link in 1968, 1969, 1972 , 1977, 1979, 1985… A few examples to illustrate: a 1981 study found a 125% increase in breast cancer rates among OC users; a study in 1989 found a 44% increased risk; in 1993 a 40% increased risk; in 1995 a 42% increased risk; in 2006 a 44% increased risk; in 2009 a 40% increased risk. Need I go on?

         Critics claim that such research supporting a link between OC use and breast cancer used only the old high-estrogen formulations of the Pill, doses no longer in use, this despite more recent studies that continue to document significantly increased cancer rates even when women use lower-dose contraceptives. (Have they forgotten that the now-discredited hormone replacement therapy used the same hormones, in lower concentrations, as found in today’s Pill?) Media reports continue to quote a 1996 Oxford pooled analysis that declared only minimal elevations in cancer rates for OC users, and no cancer rate increase 10 years after discontinuing the OC, even though that study has been discredited due to many defects in research design.

         The facts: Breast cancer is a significant health concern for women. Breast cancer rates have been steadily rising over the last three decades. Currently, over one in eight women will develop breast cancer in her lifetime. In 2005, the International Agency for Research in Cancer raised estrogen-progestogen oral contraceptives to a group 1 carcinogen classification, the highest possible rating. That is the same rating class as asbestos and tobacco, in fact. This means that sufficient evidence has been found that oral contraceptives cause cancer in humans. Mayo Clinic most recently declared “a measurable and statistically significant” connection between the pill and pre-menopausal breast cancer. Cancer risk is influenced by the age the woman starts using the OC and the stage of her reproductive life when she uses them. Elevated risk is greatest in women who begin taking OCs before the age of 20 and in women who use OCs before giving birth of their first child, a time when breast tissue is thought to be more susceptible to carcinogens. This data comes from a 2006 study from the Mayo Clinic which collated data from 23 retrospective studies, most of the research done after 1980, 21 of which showed a statistically significant increase in breast cancer (and cervical & liver cancer) among OC users. While oral contraceptive use decreased the rate of uterine & ovarian cancer, the greater increase in deadly forms of breast, cervical, and liver cancer resulted in a total increase of 58,000 cases of cancer over-all, and 6500 more deaths in 2006, according to the American Cancer Society. (“Oral Contraceptive use as a Risk Factor for Pre-menopausal Breast Cancer: A Meta-analysis,” 2006, Dr. Chris Kahlenborn et. al.)

         Keep this in mind the next time you hear someone attack the Catholic Church for refusing to support contraceptive use (or to supply them to employees). Why this media silence about oral contraceptive cancer risks? What can be gained by withholding such important medical information from women?