Physicians, breast cancer organizations, and activists on both sid Controversy Over Abortions/Breast Cancer Risk Heats Up (dateline March 19, 2001) | Breast Health News | Imaginis - The Women's Health & Wellness Resource Network

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Controversy Over Abortions/Breast Cancer Risk Heats Up (dateline March 19, 2001)

Physicians, breast cancer organizations, and activists on both sides of the abortion issue continue to debate whether abortion increases the risk of breast cancer. Five U.S. states currently require abortion providers to give patients informed consent literature which includes information on a possible link between abortion and breast cancer risk, and at least 11 states are considering legislation that would require abortion clinics to tell parents about the potential risk. This infuriates physicians like Susan Love, MD, a vocal breast surgeon who argues that state legislators would be raising "unwarranted concerns" by imposing such mandates. To further complicate matters, groups such as the Coalition on Abortion/Breast Cancer point out that some studies do support the link between abortion/breast cancer risk while other organizations such as the American Cancer Society and the National Cancer Institute say those studies are flawed and other data, which do not show any risk, should be considered instead. So what do women need to know?

First, the link between abortion and breast cancer risk has always been controversial because the debate is influenced by emotional and socio-political components. Also, determining which abortion studies are valid and which are flawed can be difficult. Study results can be influenced by a number of factors including:

  • The number of cases observed; a very small number may not reflect the general population
  • The type of abortion: induced versus spontaneous (also called miscarriages)
  • Accounting for other lifestyle or genetic factors that may influence breast cancer risk
  • The amount of time between abortion and breast cancer occurrence
  • Data limitations due to the changing legal status of abortion (for example, an American woman’s abortion history may not have been reported before 1973, when the Supreme Court legalized abortion)
  • Recall bias (women may not accurately report their reproductive history)
  • Emotional, social and political factors, including personal stances on abortion

What Do the Studies Show?

While the data on abortion and breast cancer risk are mixed, most breast cancer advocacy and women’s health organizations accept that abortion does not increase the risk of breast cancer. This view was solidified after the release of a large Danish study that included 1.5 million women born between April 1935 and March 1978. The study found that the risk of developing breast cancer for women with a history of induced (purposed performed) abortion did not differ from the risk for women without a history of induced abortion. In this study, the researchers were able to avoid recall bias (a significant problem in some studies) since the information on abortions was collected before breast cancer developed.

Several reputable organizations, including the American Cancer Society, the National Cancer Institute, the World Health Organization, the National Women’s Health Network, and the National Breast Cancer Coalition support the results of this study. However, others argue that previous studies have shown different results.

For example, in a study published in the Journal of the National Cancer Institute in 1996, researchers found a 90% increase in breast cancer risk (1.9 times the average risk) after induced abortions. Another study reported in the same journal in 1994 showed a 50% increased risk of breast cancer (1.5 times the average risk) from induced abortions.

However, Dr. Love and others say there are flaws in both of these studies. In the first study which found a 90% increase in breast cancer risk from abortion, researchers suggest that this figure could be influenced by inaccurate recall and underreporting of abortions by the women in the study who did not have breast cancer. They point out that the study was conducted in a religiously conservative region of The Netherlands, which may have influenced abortion reporting. Similarly, in the second study which found a 50% increase risk of breast cancer from abortion, the study did not take into account a number of other potentially important factors, including the number of abortions the women had, the women’s ages at the time of the abortions, and the length of the pregnancies before the abortions. Furthermore, the study did not show any increased risk between spontaneous abortions (miscarriages) and breast cancer risk. Because of the possible inaccuracies, researchers say that the study does not permit scientific conclusions.

Why Has Abortion Been Linked To Breast Cancer Risk?

While there has not been any conclusive evidence that a history of abortion increases a woman’s risk of breast cancer, abortions have been suggested by some to increase breast cancer risk because of the involvement of the female hormone estrogen.

Near the beginning of pregnancy, estrogen levels increase so that the breasts may prepare to produce milk. After the woman gives birth, estrogen levels decrease again. In fact, full-term pregnancy (especially at a young age) has been associated with a reduced risk of breast cancer in medical studies. However, there has been some concern that if the pregnancy is aborted, a woman’s estrogen levels would continue to remain elevated for a period of time, possibly increasing the risk of breast cancer. There is also some speculation (although not proven in human studies) that the breast duct cells, which normally go through a complete cycle of growth, development, and regression during pregnancy and lactation (breast-feeding), may be changed in some way, possibly leading to an increased risk of cancer.

With the issue of abortion aside, researchers have identified several other accepted factors that increase a woman’s risk of developing breast cancer. These risk factors include:

  • Advancing age
  • Family or personal history of breast cancer
  • Genetics (specifically, mutations of the BRCA1 or BRCA2 genes)
  • Having the first child after age 30 or never having children
  • Early menstruation (before age 12) or late menopause (after age 50)

How Has the Debate Recently Evolved?

While the relationship between abortion and breast cancer risk has always been controversial and discredited by many organizations, several U.S. states are nonetheless considering legislation that would require abortion providers to inform parents about the possible connection. At the moment, Mississippi is the only state that requires such disclosure; however Montana, Louisiana, Kansas, and Texas all require abortion clinics to give patients informed consent documents that address the possibility of an increased breast cancer risk from abortion. Aided by the religiously conservative group, Concerned Women for America, the Illinois State Senate recently approved a bill that would require a task force to further study the link between abortion and breast cancer risk (the bill still needs approval from the Illinois state assembly).

In addition to legislation, abortion providers are also being served with lawsuits. In April 2000, a 19-year old woman filed a lawsuit against the physician who performed her abortion two years earlier. The woman, who does not have breast cancer, claims that she would not have had the abortion if she knew about the possible increased cancer risk and wants damages to cover future breast cancer screening and other medical costs.

A similar case has also been filed in North Dakota, where a 23-year old woman is suing an abortion clinic for false advertising since a clinic brochure did not mention the risk of breast cancer from abortion. Debates also surround groups who are invoking their U.S. Constitutional right of free speech by posting flyers that say abortion causes breast cancer.

There does not appear to be any end in sight for the abortion/breast cancer risk controversy, which is fueled with emotion from "pro-life" and "pro-choice" advocates as well as physicians, breast cancer organizations and other women’s groups. Furthermore, a randomized, controlled study of the issue is not possible because it would require researchers to decide which women in the study should receive abortions and which should not. Thus, researchers will have to continue to rely on cohort studies (such as the Danish study of 1.5 million women), in which women with and without a history of abortion are followed to see who develops breast cancer in the future—and whether the disease was actually caused by abortion.

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