Study counters claim of abortion cancer risk
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January 8, 1997
Web posted at: 9:45 p.m. EST
From Correspondent Al Hinman
BOSTON (CNN)-- It's more than a scientific debate; it's become part of the fight over abortion itself.
Medical researchers for decades have tried to determine whether abortions really increase the risk of breast cancer.
Last fall, researchers insisted they'd proved it by showing that women who'd had an abortion had a 30 percent greater risk of breast cancer.
But that's wrong, according to the latest research published Thursday in the New England Journal of Medicine.
According to a study of nearly 281,000 women in Denmark, having an abortion does not increase a woman's chances of developing breast cancer.
"The women who had had abortions had exactly the same risk of developing breast cancer as the women who had not," said Patricia Hartge, an epidemiologist at the National Cancer Institute.
Danish study avoids reporting bias
She also said that the Danish researchers' use of medical registries removed the potential for "reporting bias."
Epidemiologist Joel Brind was the co-author of the study last October which claimed to find "overwhelming" evidence that women who had an abortion face a risk of breast cancer that is one-third higher.
However, that study did not involve original research. Instead, it relied on 23 earlier studies involving more than 60,000 women. The technique, which is called meta-analysis, is controversial because conclusions can be influenced by which studies are selected for analysis.
"Reporting bias is the 'Loch Ness monster' of abortion-breast cancer research," Brind said. "They keep claiming it's there, but every time they offer some kind of evidence for it, it's not credible."
The new study avoided the issue because it examined the records of all Danish women born between April 1, 1935, and March 31, 1978.
Combining data from Denmark's registries for cancer and induced abortions, the team found no difference in the breast cancer rates for women who had had an abortion and women who had not.
U.S. researcher says study flawed
Brind insists his study is still valid and points out that the Danish researchers admitted to possible statistical
problems of their own.
Regardless of the scientific debate, says Hartge, "Whether to have an abortion is a wrenching, vexing, difficult
personal decision, and a woman will consider many issues."
If the Denmark study is valid, the fear of increased risk of breast cancer need not be one of the issues.
Reuters contributed to this report.
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