Mammograms, Induced Abortion, and the Marlboro Man


New studies seem to come along regularly these days, which contradict what was widely – and just recently – supposed to be beneficial to health. Who can keep track any more of how much coffee, cholesterol, and exercise is ideal? This situation might be conducive to the holy indifference that St. Ignatius of Loyola counseled towards the goods of this world, such as health and wealth. But indifference towards the public health authorities usually lacks that sublimity.

A recent edition of the New England Journal of Medicine contained an article that might be classified as the latest salvo in the “mammography wars.” It essentially concluded that abolishing mammography-screening programs is preferable to the status quo because they actually do more harm than good. An independent Swiss Medical Board arrived at this recommendation after a thorough review of the evidence.

The first thing they noted was that current debates revolve around outdated trials. However, treatment itself has improved considerably in recent decades, thereby wiping out the modest gains mammography was thought to confer.

Second, there are the unintended harms of the procedure, particularly those that stem from overdiagnosis. That technical term refers to dormant cancer, or precursors to cancer, detected by mammography that actually pose no threat.

Another recently published Canadian survey, featuring twenty-five years of follow-up, found that almost 22 percent of the cancers detected by mammography were overdiagnosed, resulting in unnecessary treatment, including surgery, radiotherapy, chemotherapy, or some combinations thereof. The Canadian scholars also concluded that annual mammography does not contribute to reduced mortality.

These conclusions will likely strike some as jarring, particularly since women, by and large, tend to radically overestimate the protective benefits of mammography screening. One large survey found women overestimated – by eighty fold! – the windfalls of screening; they also supposed that death from breast cancer among those not screened was thirty-two times as high as it actually is.

The Swiss team noted that their findings have been met with a certain hostility, to which they countered that, yes, one “argument was that the report unsettled women, but we wonder how to avoid unsettling women, given the available evidence.”

Not everyone agrees; the debate rages on.  It seems fair to say, however, that if there are certain gains to be had from mammography, they presently appear marginal at best. For women of the relevant age groups and for their doctors, the dilemma is easy to appreciate. Trade offs must be considered, and in weighing the possible benefits against the possible harms, not everyone would choose the same course of action.

There is one thing that all sides agree on, because everyone explicitly couches their arguments in the following terms: women deserve the most accurate information.  An exception to this operating principle is allowed, however, when it comes to a factor that, unlike mammography, has the potential to curb incidence rates: the relationship between induced abortion and subsequent breast cancer.

What basis exists for such a claim?  The vast majority studies, dating back to 1957, have indicated an association. Every single one of the statistically significant findings indicates a positive association, whereas every one suggesting a negative association is not statistically significant. 

A highly important meta-analysis, consisting of thirty-six studies from fourteen provinces in China up to 2012, recently yielded several significant findings. Women with a history of induced abortion were at 44 percent higher risk of developing breast cancer, compared with women who had not had one. Here’s what that means: supposing that the overall risk of developing breast cancer over the course of a lifetime is, say, 10 percent. Procuring an abortion would cause the overall risk to jump to 14.4 percent.

This Chinese review corroborates a similar 1996 meta-analysis that found an overall 30 percent increased risk.  Indeed it is even more compelling; not only is the estimated risk moderately greater, but a clearly evident “dose effect” also emerged. This refers to the fact that risk rises as exposure to a hazard rises; the existence of a dose effect is regarded as lending further credence to a plausible theory. They found that risk rose to 76 percent among women with two induced abortions, and again to 89 percent among women with three abortions.

Strong as these finding are, they are not enough to constitute proof. We also need a physiological mechanism of action. But we have that too.  It essentially boils down to estrogen exposure: the more of it, the greater the risk. In the early phases of pregnancy, a woman is exposed to massive amounts of estrogen, which triggers a proliferation of the types of breast lobules most susceptible to cancer.  This is why a woman who delivers prematurely (i.e. prior to thirty-two weeks) faces twice as much risk of breast cancer. It is only in the latter weeks of a typical pregnancy that other hormones begin to help transform those vulnerable lobules into cancer-resistant lobules.  Giving birth, as no one contests, is protective.

Any epidemiologist worth his salt would see that these combinations of factors deserve to be taken seriously. Shunning intellectual honesty, however, the authorities have worked overtime to conceal the relationship. One way they have done so, incidentally, is to conflate induced abortion with spontaneous miscarriages, which are not a risk factor.

Far more profitable than disguising the truth so that women will not become “unsettled” would be to rectify this ongoing travesty. The National Cancer Institute is, in effect, misleading women, saying (according to the numbers) that abortion’s equivalent of “the Marlboro Man is not in greater danger of lung cancer than the non-smoker.”

Is there any doubt who has more clout: Big Tobacco or Big Abortion? The health authorities dare to look the other way for only one of these industries, wholly indifferent to the lives and health harmed by the other. 

Matthew Hanley’s new book, Determining Death by Neurological Criteria: Current Practice and Ethics, is a joint publication of the National Catholic Bioethics Center and Catholic University of America Press.