Abortion and Breast Cancer:

The doctor doth protest too much, methinks

By Joel Brind, Ph.D.

Here I go againplaying right into their hands: "Brind has publicized his findings widely at pro-life meetings." So reports Dr. Tim Davidson in a high profile "Personal View" article in the December 2001 issue of Lancet Oncology, a publication of the United Kingdom's most prestigious medical journal.

Davidson's papertitled "Abortion and breast cancer: a hard decision made harder"is a review of reviews, of sorts, on the abortion-breast cancer link (ABC link). It is clearly designed to show that by a margin of three to one the consensus of reviewers is that the evidence for the ABC link is unconvincing. The "one" is my own "comprehensive review and meta-analysis" which I and three colleagues published back in 1996 in the British Medical Association's epidemiology journal.

Then, Davidson proceeds to my "pro-life" publicity, and that " Critics of the paper have raised concerns." You get the picture: By the end of the paper, one would think the ABC link is pure pro-life propaganda.

What to make of this? It is noteworthy, for starters, that he summarizes our paper's results and conclusions quite accurately.

We did indeed report a statistically significant, 30% overall increase in breast cancer risk among women who had chosen abortion. That was the result of our summary of all available worldwide published data. And we did indeed conclude "that induced abortion should be regarded as an independent risk factor for breast cancer, irrespective of parity or timing of abortion relative to first term pregnancy."

What is most curious about the Davidson paper is that no sooner does one read erudite, clearly written, and accurate passages, then one comes upon misrepresentations which take the breath away from any reader well versed in the subject.

Take, for example, Davidson's lucid explanation for the theory behind the ABC link. A breast surgeon himself, he lays out the physiology and hormonal dependence of breast development with superb clarity, even including an excellent diagram of breast tissue structure.

He presents the "hypothesis that undifferentiated breast epithelial cells are stimulated by the high concentrations of oestradiol (estrogen)" early on in a normal pregnancy. If the pregnancy goes to term, "these cells achieve full differentiation," which makes them resistant to carcinogens.

If the pregnancy is aborted, he writes, there remain in the breast "proliferated and supposedly vulnerable cells, which are more susceptible to carcinogens in later years."

So far, so good (in fact, very good). He even faithfully recounts the accounting of why most miscarriages do not increase the risk of future breast cancer: "low circulating maternal oestrogen concentrations."

But what a polysyllabic prevarication then follows: "There is no histopathological or morphological verification of any such epithelial susceptibility and the hypothesis remains just that--a theory only."

This is patently false. Not only did Drs. Russo and Russo--back in 1980--publish the landmark experimental work in rats which clearly demonstrated the "theory," but they also subsequently showed the same patterns of development in human breast tissue.

And then, Dr. Janet Daling, in her famous 1994 ABC study on women, related her findings of increased breast cancer risk to those findings of Russo and Russo. None of these researchers are pro-lifers.

But to those not well-versed in the documentation that supports the connection between breast cancer and induced abortion, Davidson's assertion that such evidence does not exist does indeed make the ABC link look speculative.

Moving on to the "concerns" that "critics have raised," the reader is led through a shopworn litany of studies which supposedly prove that the ABC link is really just an artifact arising out of something called "recall bias." In other words, says Davidson (as if it were an uncontested fact), healthy control women who've aborted have been more reluctant to report on a controversial, emotionally charged subject such as induced abortion, than have women who've aborted and now have breast cancer. In other words, healthy women lie about abortion, women with breast cancer don't.

Were this true, it would artificially inflate the results, making it seem as if women with breast cancer patients had had more abortions than had healthy women. The trouble is, there is no credible evidence that recall bias applies in ABC research. On the contrary, there is plenty of evidence that "recall bias" does not take place in this context.

But Davidson keeps misleading the reader down the trail of ABC denial, summarizing the conclusions of three other review papers. He even includes a table to show the 3-1 margin of reviewers' opinion, "that induced abortion does not increase a woman's risk of breast cancer later in life."

Now this is quite curious in and of itself. On the one hand, the doctor is trying to explain how "a simple numerical count of papers"--primary epidemiological studies--cannot be considered reliable evidence of a link. This is what we did in our 1996 mega-analysis.

But on the other hand, he has no trouble using a "simple numerical count" of secondary opinions as convincing evidence!

However, it's Davidson's "Conclusions" that really send a chill down any ethical spine. "Primum non nocere, first do no harm," he says, quoting Hippocrates, as if to command the moral high ground.

Then this: "In the absence of robust evidence that an increased risk of breast cancer in later life is relevant to her deliberations, a woman deciding whether to opt for termination or to continue with an unwanted pregnancy has a hard enough task without being made to confront the breast cancer issue."

He goes on to set the proverbial bar for proof of the ABC link astronomically high: "Until consistent and conclusive evidence of a causal link can be shown, her decision need not be made more difficult by having to entertain hypothetical future risks."

But it is Davidson who trips here, for even as he echoes the title of his essay, he gives away his pro-abortion--not "pro-choice" by any stretch--point of view.

The title of the piece is: "Abortion and breast cancer: a hard decision made harder." Isn't that only true if the decision is for abortion? After all, if the decision is against having an abortion, that decision is made easier--not harder--by the consideration that abortion's legacy can be ill effects on the mother.

Dr. Davidson really needs to follow his own advice, given in his literal bottom line: "Personal bias has no place here." Indeed!

Joel Brind, Ph.D., founder and President of the non-profit Breast Cancer Prevention Institute in Poughkeepsie, New York, and professor of human biology and endocrinology at Baruch College of the City University of New York.