Cool heads are needed on the abortion-breast cancer link

Ostracism, scorn and denial are not good strategies for dealing with an important public health issue.
David van Gend | Aug 27 2014 | comment  



A Mexican wave of moral indignation swept through the chattering class this month in Australia when the hypothesis was raised of a link between abortion and breast cancer. We heard, in shrill tones, that claims of such a link are “factually incorrect” (blogger Mia Freedman), “absurd” (Simon Breheny of the IPA) and even “an insult to all women” (Greens MP Adam Bandt). With the arrival this week of breast surgeon and cancer researcher Dr Angela Lanfranchi to speak to this hypothesis, we can expect a resurgence of this rage.

Yet no such public frenzy occurred when the closest male equivalent – a correlation between vasectomy and prostate cancer – was proposed only last month. Why is it a slur against women to consider a link between abortion and breast cancer, but no slur against men to suggest that vasectomy might be linked to prostate cancer? Both hypotheses remain unproven, plagued by conflicting evidence, yet both deal with grave medical issues that demand ongoing dispassionate research.

Consider last month’s publication on prostate cancer in the Journal of Clinical Oncology. It was a 24 year follow-up study and concluded, “Our data support the hypothesis that vasectomy is associated with a modest increased incidence of lethal prostate cancer”. Yet look back over that 24 year period and you will see that the vasectomy-prostate cancer hypothesis has waxed and waned, just like the abortion-breast cancer hypothesis.

In 1993 the Journal of the American Medical Association investigated the question, “Vasectomy and prostate cancer: chance, bias, or a causal relationship?” and made the point that “any causal relationship between the two would be important both for individual and public health”. The same point should be calmly made about any relationship between abortion and breast cancer. A decade later, the ABC’s Health Report commentator Dr Norman Swan exulted in newer prostate research published in the same prestigious journal, telling his male listeners, “There has been some concern about an alleged increased risk of prostate cancer after vasectomy. But recent research from New Zealand found no link between them - so the only excuse now is cowardice!”

Contrast the good-natured commentary on the prostate cancer theory to the vulgar chorus of denunciation of the breast cancer theory.

Yet if the link between abortion and breast cancer is not worthy of consideration, why does the question keep being raised in peer-reviewed medical journals? When four of the five largest studies on this subject in the past two years report a significant correlation, why did medical authorities stand by this month and let this inoffensive hypothesis be lynched by an ignorant mob? Worse, why did the President of the AMA, Dr Brian Owler, do such injustice to the published research with his categorical statement, “There is no evidence to say breast cancer and abortion are linked. Let’s not use false evidence or try and link abortion with other things such as breast cancer.”

The truth is far more interesting, and concerning, than Dr Owler’s dismissive sound bite. Pause and consider just three major studies from the last three years.

In February this year in the journal Cancer Causes & Control, Huang et al published “A meta-analysis of the association between induced abortion and breast cancer risk among Chinese females”. After analysis of 36 studies covering 14 provinces in China the authors concluded, “Induced abortion is significantly associated with an increased risk of breast cancer among Chinese females, and the risk of breast cancer increases as the number of induced abortions increases.”  

By contrast, last year a large Danish study investigated “Induced abortion and breast cancer among parous women” and concluded, “Our study did not show evidence of an association between induced abortion and breast cancer risk.” (Brauner et al, in Acta O&G Scandinavica)

In the journal Breast Cancer Research in 2012, Lecarpentier et al investigated “Variation in breast cancer risk associated with factors related to pregnancies” in the cohort of French women who carry the breast cancer genes BRCA 1 and 2. They concluded: “We found an increased breast cancer risk associated with an increasing number of induced abortions.”

Take a closer look at the Lecarpentier paper, which was a model of sober caution and acknowledged the contentious nature of this topic: “A number of studies have examined the risk of breast cancer associated with interrupted pregnancies, but there has been some controversy in the past.”

After reviewing some studies with negative findings they state, “However, numerous studies have suggested that interrupted pregnancies may moderately increase the risk of breast cancer”.

As with all rigorous medical research this paper looked for a biological explanation for their positive findings. They note that completing a pregnancy prior to any subsequent abortion was strongly protective against breast cancer – which is a widely accepted finding – and postulated, “This effect may be because the differentiation of mammary cells which occurs during a full –term pregnancy prevents the carcinogenic effect of subsequent interrupted pregnancies.” That hypothesis – of interrupted pregnancies being carcinogenic because they arrest breast cell development in an immature and vulnerable state, and the related finding that the cancer risk is strongly mitigated by an initial full-term pregnancy - is exactly the hypothesis Dr Lanfranchi will be discussing on her speaking tour, yet for some reason she is not accorded the same respect as the Lecarpentier team.

Finally, the French study proposes a scoring system “useful for the individual estimation of breast cancer risk” based on a number of variables such as the stage of abortion, the number of abortions, and whether there was a protective full–term pregnancy at the start. Such a scoring system would allow closer screening of higher-risk individuals, and that is a valuable tool in any cancer screening programme.

So why would the AMA President treat with such contempt research which might help women know they are higher-risk and therefore needing closer screening? 

Instead he issued a ruling: “There is no link between abortion and breast cancer. We need to make that very clear to the public, and certainly we should not be promoting any papers from the 1950s.”

This reference to the 1950s was in response to comments made by Senator Eric Abetz on the Ten Network’s The Project. Watch his lips as he speaks the words that lit the fuse of this month’s media frenzy: “I think the studies, and I think they date back from the 1950s, assert that there is a link between abortion and breast cancer”.  

Abetz was correct, and if Dr Owler was so inclined he could read back through more than seventy published studies between 1957 and 2014 and find that more than three quarters of them (of widely varying quality) assert a correlation between abortion and breast cancer. So where is the cause for offense in the Senator’s statement?

Abetz made clear that he was not going to make a judgement on the “factual correctness” of the hypothesis saying, “I don’t have that scientific expertise” but he simply reported the fact that many studies do “assert that there is a link”.

No problem with that, but his interviewer on The Project, Mia Freedman, pontificated, “It is conclusively and scientifically incorrect”, and having closed the interview she turned to the panel and played the holocaust card: “When people are actually having scientifically incorrect information that’s incredibly disturbing. I mean, would they get up and support holocaust deniers? This is the same thing essentially”.

After Freedman’s immoderate analogy the hysteria only worsened. Her fellow blogger at Mamamia, Shauna Anderson, wailed: “This Senator just undermined millions of breast cancer sufferers around the world.” Greens MP Adam Bandt thundered, “The minister should not scare young women by peddling his dark, anti-choice ideology on national television” and demanded he apologise.

Further, Bandt stipulated that Abetz not attend the upcoming branch meeting of the World Congress of Families, a homely gathering in a church hall in suburban Melbourne this coming Sunday – free entry, bring your own tea bag - where the co-director of the Sanofi-Aventis Breast Care Centre in New Jersey intends to commit a crime against humanity. Dr Lanfranchi will speak on the question of, “Induced abortion and breast cancer – is there a link and should it be a part of informed consent?”

She thinks it should because she thinks there is, and as a breast cancer expert her evidence should be listened to and argued with respectfully. The political and moral passions about abortion must not paralyse rational discussion of the purely clinical question before us.

Social progressives should take a cold shower. Even if future studies confirm the abortion/ breast cancer link, such a finding would not threaten the sexual revolution, or its ultimate guarantor of abortion on demand. The cancer link, if it exists, would be just another prudential calculation of risk and benefit for the patient, just like the prudential calculation of risk and benefit in using the Pill, which we know is linked very weakly to breast cancer.

Social conservatives should take a cold shower if they think a link between abortion and breast cancer can or should be conscripted to the pro-life cause. Prudential calculations are not the stuff of moral argument. It is honourable to appeal to justice and duty in an attempt to reduce the present killing of every fourth baby in Australia; it is contemptible to appeal to the self-interest of some remote risk of cancer as a reason to let your baby live.

Having all chilled out, let this plausible but unproven factor in the increased breast cancer rates of recent decades be given ongoing cool consideration by experts, free of ideological filters and far from the madding crowd.

David van Gend is a family doctor in Toowoomba. He blogs at www.davidvangend.com



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