John Kindley

(WOMENSENEWS)–The debate around whether abortion increases a woman’s risk of developing breast cancer has intensified in recent years, with 15 states considering mandating that women be informed of the potential risk and two states adopting such laws.

Many researchers are troubled, however, by the trend because the weight of current scientific evidence does not seem to support a link between breast cancer and abortion.

Montana and Mississippi already require that women seeking an abortion be informed that the procedure could increase their risk of developing breast cancer. Now a trial set for March in Fargo, N. D., will force a judge to weigh in on the matter, potentially setting a legal precedent in a debate that has raged since the 1980s.

At issue is whether the Red River Women’s Clinic in Fargo may continue to give patients a brochure stating that the majority of medical evidence suggests no link between abortion and breast cancer. A false-advertising lawsuit filed against the clinic by Amy Jo Mattson, a local pro-life activist, claims that the brochure deceives women.

“What we want the brochure to say is that abortion increases the risk of breast cancer and most studies show this,” says Mattson’s attorney, John Kindley. He also is involved in a similar lawsuit against a Planned Parenthood clinic in Southern California.

Linda Rosenthal, a lawyer with the Center for Reproductive Law and Policy in New York who is representing the clinic, argues that the suit is one more attempt by pro-life activists to politicize what should really be a scientific matter.

“They purport to worry over women’s health, yet they lie about the science in an attempt to scare women from making their own choice,” Rosenthal says.

Different Studies Have Different Conclusions

Over the years studies have failed to provide definitive-enough answers, with some finding that having an abortion raised a woman’s risk of developing breast cancer while others concluded that having an abortion actually lowered the risk.

One of the things that Mattson and Kindley and his client find most irksome about the brochure is that it says there is “no established link” between abortion and breast cancer–language borrowed from a 1996 National Cancer Institute fact sheet rather than the 1999 version, which states that evidence of a link is “inconsistent.” (The institute is expected to drop the word “inconsistent” in the next version.)

The clinic originally put the contested paragraph in its brochure in response to pro-life-funded billboard advertisements in the Fargo area warning of established links between breast cancer and abortion.

Several experts say warning of a direct link is tantamount to issuing misleading information and needlessly alarms women.

“An examination of the scientific evidence makes it very clear that the overall picture is no increased risk of breast cancer to women who have had abortions,” says Patricia Hartge, an epidemiologist at the National Cancer Institute.

The institute’s updated version of its fact sheet is due out any day and Hartge emphasizes that there have been recent, “solid” studies that find no link.

Critics have their preferred studies as well in a scientific and political debate that has raged for years. Joel Brind, a biochemist at Baruch College in New York who is opposed to abortion and notably vocal on the correlation between breast cancer and abortion, will testify for Mattson at the Red River trial. He contends that the majority of studies show a link between the two and that the institute presents “lies and inconsistencies” on the topic.

Resolving the scientific dilemma of the different studies would require more than simply adding up the studies to date and averaging them out, epidemiologists say. Instead, it would require well-designed studies that examine large numbers of women and do not rely on interviews with patients to gather the data.

One Issue: Does ‘Bias Recall’ Exist?

That’s because healthy women are often unwilling to report their history of past abortions–something researchers describe as “recall bias.” But women diagnosed with breast cancer may be more likely to give an honest accounting.

“There is a very high chance women with breast cancer are more willing to soul search and more accurately report their abortion histories,” says Karin Michels, an assistant professor of epidemiology at Harvard Medical School.

Indeed, a Swedish study that found women with breast cancer were 50 percent more likely to report a prior abortion than healthy women. And a recent editorial in Lancet Oncology noted that “healthy control women have been more reluctant to report on a controversial, emotionally charged subject such as induced abortion, than have patients with breast cancer.”

Baruch’s Brind vehemently disagrees that this recall bias exists. In a report he published in a pro-life publication and on the Internet, he implies that the term itself is manufactured.

In 1996, Brind published in the Journal of Epidemiology and Community Health a combined analysis of 23 studies and found that abortion increased the risk of breast cancer by 30 percent. But all the studies he analyzed were subject to recall bias and several prominent epidemiologists have questioned his methodology.

“Brind used unbelievably bad studies, and if data weren’t available he used inferred data, something that is just not standard practice in epidemiology,” says Lynn Rosenberg, a professor of epidemiology at the Boston University School of Public Health.

Estimated 43 Percent of Women Will Have Abortion by Age 45

A year after Brind’s criticism of previous studies was published, Dutch researchers published a new study in the New England Journal of Medicine that has since become the gold standard on possible links between abortion and breast cancer. It eliminated the problem of recall bias by using government-mandated abortion registries and linking them with the Danish Cancer Registry to compare women’s medical histories. (No similar records are available in the United States.) A whopping 1.5 million women were involved in this “record-linkage” study, which decreased the chance that the overall findings would be due to chance.

In the study, Dr. Mads Melbye found that women who had induced abortions had no increased risk of breast cancer. Researchers praised the study on several fronts: its size, the fact that it eliminated recall bias and the prospective or forward nature of its design, which researchers believe yields more reliable results.

“The Melbye study is a rotten study,” insists Brind, who criticizes the five-year reporting-period difference between when the study began tracking breast cancer in 1968 and the abortion-tracking portion that did not start until the procedure was legalized in 1973.

In June 2000, Dutch researcher Matti A. Rookus published a commentary in the American Journal of Epidemiology finding that “the most impressive study published to date is the Danish national follow-up study by Melbye.” Rookus added that although it was not clear why Melbye’s study contained the reporting difference, the overall work of the paper was sound and the study findings would not have been affected by the difference.

Other Studies Rely on Records, Not Disclosures

Since the 1997 Melbye study, other studies have been published that avoided the problem of recall bias. An Oxford record-linkage study published in the Journal of Epidemiology and Community Health found previous abortion to be slightly less common in women with breast cancer–that is, no link was found.

Polly Newcomb, a researcher at the Fred Hutchinson Cancer Research Center and an affiliate professor at the University of Washington School of Public Health and Community Medicine, published a study in 2000 that evaluated health-care records of women in the United States rather than relying on patient interviews. Her study also found no link between abortion and breast cancer.

“The good studies since Melbye continue to show that women who have had induced abortion have the same risk as women who have not,” said the cancer institute’s Hartge.

“The scientific evidence does not support the association between induced abortion and breast cancer,” says Joann Schellenbach, the national director of medical and scientific communication for the American Cancer Society. “We would advise women considering abortion that they should not be concerned with an added risk of breast cancer.”

Despite such strong words from two such well-regarded sources, the leadership of the conservative public policy group Concerned Women for America remains convinced that there is a link between abortion and breast cancer and the group is actively lobbying for legislation that would support laws asserting the link exists.

“We have looked at the evidence and it is clear that there is a link,” says Wendy Wright, the organization’s spokeswoman. She adds that Brind has gone over the evidence with their group and that she herself had vetted the studies.

Wright dismisses the idea of recall bias as a “ridiculous thought” and then points to a 1989 study in New York that did not rely on patient recall but used health records to establish a patient’s past abortion history. The study found a 90 percent increase in risk of breast cancer in women who underwent abortions.

Both Newcomb of Washington University and Michels of Harvard say they found that older study lacking. “It looked only at very young women and did not eliminate confounders,” Newcomb said, referring to factors such as a family history of breast cancer that may “affect or confuse” a study.

Because an estimated 43 percent of women will have an abortion by the time they are 45, the topic has generated heat in cities around the country. Kim Gandy, president of the National Organization for Women, says her organization worked in the past to have public transportation ads pulled in Philadelphia that warned, “Women who choose abortion will suffer more and deadlier breast cancer.” CHRIST’s Bride, Ministries, a nonprofit, religious education group had sponsored the ads.

Gandy says she would like to see future studies that fully factor in a woman’s reproductive history.

“We know that early pregnancy has a protective effect against breast cancer and this will need to be factored into future studies that compare women’s risks,” Gandy said.

Michels is currently working on a study of 700,000 women that factors in their reproductive histories and expects to have her results by fall of 2002. The study will look at comparable groups of women, such as those who had a child by age 25, and then break that group into those who had an abortion and those who did not.

In the meantime, a new editorial published in Lancet Oncology by breast surgeon Tim Davidson argues that the current evidence is insufficient to justify a warning to patients considering an abortion–a view he says is endorsed by the Royal College of Obstetricians and Gynaecologists.

The Lancet Oncology editorial may bode well for the Red River Women’s clinic in Fargo and more research into breast cancer may ultimately improve prevention, detection and treatment. Harvard’s Michels says that the end point of all the research is the female patient.

“At the end of the day this is about a search for the truth, whatever truth that is,” she says.

Margaret Woodbury is a freelance journalist based in New York.

For more information:

National Cancer Institute
“Abortion and Breast Cancer”:

Planned Parenthood Federation of America, Inc.
“Anti-choice Claims About Abortion and Breast Cancer”:

Concerned Women for America”Abortion Clinic on Trial”: