Chinese researchers have thrown their weight into an already contentious debate over abortion and breast cancer. In China, where breast cancer has increased sharply in recent years, a new review found that women who had an induced abortion were 44 percent more likely to develop breast cancer than those who didn’t.
Cancer Causes & Control published the review—a meta-analysis of 36 Chinese studies of abortion and breast cancer—online late last month. Yet most mainstream media have ignored the review, unwilling to explore a link many pro-abortion researchers have dismissed. In doing so, they may be ignoring an important body of evidence in abortion and breast cancer (sometimes called ABC) research.
“From a methodological standpoint, this looks like a very good piece of work, and it leaves me with the conclusion that there is an association between induced abortion and breast cancer,” Gene Rudd, the senior vice president of the Christian Medical & Dental Associations, said in commenting on the study.
Rudd has been skeptical of some previous studies that either have or haven’t shown a cancer link to abortion. The ideological views of authors can bias their research, and women may often underreport their abortions in scientific surveys, due to shame.
“This is different. This is a positive step forward in terms of the quality of the research, the elimination of biases, the use of screening,” Rudd said.
He added that although the review showed a stronger abortion and breast cancer link than previous research, it doesn’t prove cause and effect: “It’s not the final answer.”
Breast cancer in women involves a variety of risk factors, including diet, age, smoking habits, and family history. ABC research has proved difficult because of those confounding factors, and because of the delay between the time women have abortions (usually in their teens or 20s) and the time they develop cancer (often after age 50).
The subject is also a political hot button. Researchers who view abortion as a women’s rights issue don’t want to suggest it is causing breast cancer. The National Cancer Institute, the American Cancer Society, and the American Congress of Obstetricians and Gynecologists have all formally denied any causal relationship between abortion and breast cancer. Rudd’s group has acknowledged there is evidence on both sides of the debate and has recommended that doctors inform women of the potential, but unproven, cancer risks of abortion.
In the secular medical establishment, certain lifestyle messages are taboo. Even though epidemiologists all agree that young motherhood and breastfeeding reduces the risk of breast cancer, “You don’t have much advertising saying, ‘Have a child at a young age in order to avoid breast cancer,’” said Patrick Carroll, a statistician in the United Kingdom who has written about the risk of breast cancer after abortion.
Carroll said the Chinese meta-analysis provides a “fresh angle” on the subject because Chinese research doesn’t seem to have gotten much attention in the West.
Joel Brind, a researcher at Baruch College in New York City, noted earlier this month that the Chinese review showed a strong “dose effect”: A woman’s risk of breast cancer was greater if she had two or more abortions (76 percent increased risk), or three or more abortions (89 percent increased risk). Brind co-authored a meta-analysis in 1996 that found a 30 percent increased risk of breast cancer after abortion, globally.
In China it is common for women to have multiple abortions. The Chinese authors of the new review, led by Yubei Huang of the Tianjin Medical University Cancer Institute and Hospital in Tianjin, China, wrote that there was a lack of social stigma surrounding abortion in China. In theory, that should reduce the problem of women denying past abortions when filling out research questionnaires, an issue that may skew some ABC research.
Abortions are common in China because of the nation’s one-child policy. Many secular Chinese don’t view an unborn child as a person, and the communist government is careful to suppress pro-life messages that might come from Christian or Buddhist groups.
Chinese abortions among single young women have increased in recent years, and there remains a strong cultural stigma attached to teen motherhood. Zhou Anqin, a manager at an abortion center in Xi’an, told The Associated Press in 2011, “The moral outrage over having a child before marriage in our society is much stronger than the shame associated with abortion.”
Researchers who advocate an ABC link say the problem results from pregnancy hormones that cause the growth of cancer-vulnerable breast tissue. When a pregnancy is unnaturally cut short before 32 weeks of development, the breast tissue doesn’t have a chance to gain long-term cancer resistance.