Abortion Breast Cancer - a myth?

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An article in the Lancet rehashed the subject of the link between abortion and breast cancer. Dr Beral, the lead scientist concluded that there was insufficient proof of a link - she based this conclusion on her metastudy of several available studies. The media triumphantly picked up the headline, shouting that the abortion breast cancer link was a "myth".

An article in the November edition of the journal "Ethics and Medicine" points out that Beral's metastudy was flawed and if it had been organized in a better manner, it would have NOT "disproven" the link.

Below is a brief listing of the fatal flaws in Dr Beral's study, flaws which you will never read in the mass media:

1. Beral selected 24 studies (slightly over half) out of 41 possible studies and she excluded 3 of HER OWN studies and included 3 studies which have been proven to be flawed due to poor data collection including the famous Melbye study which listed 60,000 women who had had abortions (and got breast cancer) as NEVER having abortions, because they aborted before the computer records were kept. Were these 60,000 women added to those who had HAD abortions, the Melbye study would have shown a higher percentage of breast cancer among aborted women than some of the other studies.

By being selective with the studies included in her metastudy, Beral can skew the statistics by excluding those studies which would provide "the wrong answer" to her premise. If the reasons for which she eliminated half the studies, were applied to ALL of the studies, those studies she chose to include should have been eliminated also.

2. She chose an invalid control group. She compared aborted women to women who had never been pregnant when it is well known women who have never been pregnant are a high risk group for breast cancer because a woman's body changes dramatically hours after conception. She should have compared women who had carried full term to women who had aborted.

This comparison of women who had never BEEN Pregnant to aborted women showed LESS difference in risk of breast cancer between the two groups because women who have carried FULL TERM have a significantly LOWER risk of breast cancer than women who have never been pregnant. (This risk of breast cancer in women who have never been pregnant has been known for decades because I heard about it when I was a kid). So in other words, she compared a high risk group (women who have never BEEN pregnant) with aborted women to skew the results.

From Dr Lanfranchi's article: (details on why women who have never been pregnant are higher risk for breast cancer as are women who abort or deliver before the 32nd week of pregnancy)

>>>>>In fact, even as the National Cancer Institute discounted the ABC link, it did so while also admitting an “epidemiologic gap,” as they put it, concerning premature deliveries before thirty-two weeks and an increase in breast cancer risk. This is not a “gap” that is inexplicable if one is aware of breast physiology as described by standard texts. Over 80 percent of all breast cancers are ductal cancers and arise in Type 1 lobules. At puberty, when estrogen levels rise, the breast enlarges partly by increasing the number of Type 1 lobules. When estrogen levels again rise during pregnancy, a woman’s breast further enlarges by making increased numbers of Type 1 and 2 lobules. The longer she is pregnant before thirty-two weeks, the more Type 1 and 2 lobules she forms. After thirty-two weeks her breasts stop enlarging and the Type 1 and 2 lobules develop into Type 3 lobules in preparation for breast-feeding. These Type 3 lobules are resistant to carcinogens. This is the reason that women who have given birth have a lower breast cancer risk than women who have never been pregnant.<<<<<

This is not the first instance where a selective metastudy has been used to "prove" an unsafe procedure to be "safe". The same technique was recently used to advertise gastric bypass surgery as "safe and effective". In that metastudy, only 141 studies were selected (all of "new ops" who are known to be lower risk)... out of some 900 studies available!

The following comment in Dr Lanfranchi's article seems so appropriate:

>>>>Studies that take data from many previous studies and reanalyze” them (or put them into a meta-analysis) need to have sound scientific reasons for excluding some published studies. Without valid exclusion and inclusion criteria, the results can be skewed and inaccurate because they may allow an author’s personal bias to consciously or subconsciously enter the selection process, thus corrupting the conclusion. Undoubtedly, this sort of bias is what has led some observers to call epidemiology a pseudoscience.<<<<


1. Angela Lanfranchi, M.D., F.A.C.S. Breast Cancer Prevention Institute Poughkeepsie, New York: "The Abortion-Breast Cancer Link Revisited" (Ethics and Medicine, Vol 29, 11 November 2004)

Available on line:

2. Ellen Goodman, “Just the Schmacks, Ma’am,” Boston Globe, May 13, 2004.