Study: No link between abortion and breast cancer
By Judy Peres
Copyright © 2007, Chicago Tribune
Published April 24, 2007
A new study from researchers at Harvard University has set the pot boiling again over one of the most perturbing questions in the abortion wars: Does terminating a woman's pregnancy increase her chances of developing breast cancer?
The study, in this week's issue of the Archives of Internal Medicine, followed more than 100,000 women from the landmark Nurses Health Study for 10 years. It found no link between abortion and breast cancer, and none between miscarriage and breast cancer.
A comprehensive review of the scientific evidence conducted in 2003 by the National Cancer Institute reached the same conclusion, and most experts thought the issue had been put to rest. But abortion opponents continue to insist the link is real, and at least four states (Texas, Mississippi, Minnesota and Kansas) require that women seeking abortion be told as part of their mandatory counseling that the procedure could cause breast cancer.
The national Coalition on Abortion/Breast Cancer immediately rejected the new study as flawed.
"These are the same researchers that told us in 1991 that by taking combined hormone replacement therapy women would be protected from heart attack and stroke," said Karen Malec, president of the coalition. "In this [new] study, they are using the same study design and the same population base. They were wrong about HRT then, and they're wrong today about induced abortion."
Malec said lawmakers "have a moral obligation to require abortion providers to tell women that if they have abortions they'll have a greater breast cancer risk than they would have had if they had their babies."
It is well established that a full-term pregnancy before age 35 reduces a woman's risk of being diagnosed with breast cancer, but the question of whether an incomplete pregnancy at any age affects that risk is less clear. Most studies of miscarriage and breast cancer have found no association. Studies on the potential link between abortion and breast cancer reached mixed conclusions.
So in 2003 the U.S. government's cancer institute convened a workshop of more than 100 of the world's leading experts on pregnancy and breast cancer risk. They concluded that having an abortion or miscarriage does not increase a woman's subsequent risk of developing breast cancer.
Malec said of that meeting, "It was a political sham -- a whitewash. ... Most of the scientists there were government-funded and were afraid they would lose their grant money if they said abortion raised the risk of breast cancer."
As for the new Harvard study, Malec said a major problem was that researchers collected data on breast cancer and abortions for all 10 years of the study (1993-2003). So if an abortion took place late in the study period, she said, there would not have been time for a breast tumor to develop and be reported.
The lead researcher of the Harvard study, Karin Michels, told the Associated Press that more than 90 percent of the abortions reported in the study occurred before 1993.
"I don't doubt people on the religious right want to believe" in the abortion-breast cancer link, said Michael Cromartie, vice president of the Ethics and Public Policy Center in Washington, D.C. "There's a temptation for any group that's highly charged politically to say, 'Science is on our side,' and not to trust scientists who reach opposing conclusions."
Abortion opponents have increasingly tried to use science to bolster their beliefs, including opposition to emergency contraception and stem-cell research. "The Christian right has their own scientists," said Cromartie.
"No matter what the study says, if it doesn't confirm the bias of the group, they're not going to like it."