In the first of a two-part analysis, Philippa Taylor examines a medical controversy about which every woman has a right to know …
EVIDENCE of a possible link between abortion and breast cancer is mired in controversy and sensitivity, but also in ideological agendas which I believe are hiding and suppressing evidence that should be available to women.
Patrick Carroll, in an article in the Journal of American Physicians and Surgeons, claims that: ‘British medical journals are reluctant to publish papers that report a link of breast cancer to induced abortions.’ I concur and so it is this link that I am writing about.
A 2011 Royal College of Obstetricians and Gynaecologists report, The care of women requesting induced abortion definitively states that: ‘Women should be informed that induced abortion is not associated with an increase in breast cancer risk’ (p42). This report is widely cited to dismiss any evidence of a link. Another highly-publicised report by Education for Choice (EFC) states that ‘linking abortion to breast cancer and ‘post-abortion stress’ is ‘medical misinformation’, adding that Cancer Research UK has ‘confirmed that abortion does not increase the chance of developing breast cancer’.
Is this link really so indisputable? Is it really ‘medical misinformation’ to suggest that there may be a link? Is the matter settled? No, it is not.
The possible existence of a link between abortion and subsequent risk of developing breast cancer has been a cause of controversy and debate for many years, and still is.
But let’s start with what is not controversial: Carrying a first pregnancy to birth is protective against breast cancer (see here too).
This immediately shows that a woman will have a higher risk of breast cancer if she has an abortion compared to carrying to term. I wonder how many even know of this basic fact?
Breast cancer is a multifactorial disease and there are many factors which impact risk. Most, however, are related to reproduction and/or female reproductive hormones: Oral contraceptives (classified by the World Health Organisation as a Group 1 carcinogenic), nulliparity (the condition of a woman who has never given birth), late age at first full-term pregnancy, having fewer children, not breastfeeding them, high alcohol consumption, smoking cigarettes and, reported very recently, Hormone Replacement Therapy. All these increase the risk of breast cancer. Consequently, in the ‘West’ the baseline lifetime risk of breast cancer is high (around ten per cent) without considering abortion at all. So what happens when we do consider abortion as a possible risk factor for breast cancer?
A peer-reviewed research report on a group of women in India explains the hypothesis for a breast cancer link with abortion: ‘Induced and spontaneous abortion increases the risk of developing breast cancer. In early pregnancy, levels of estrogen increase, leading to breast growth in preparation for lactation.
‘The hypothesis proposes that if this process is interrupted by an abortion before full maturity in the third trimester, then more relatively vulnerable immature cells could be left than there were prior to the pregnancy, resulting in a greater potential risk of breast cancer over time. Though many studies have reported an association between abortion and breast cancer risk, the exact influence is still unclear.’
What does other research find?
The 2011 RCOG report was published before a major meta-analysis of 36 studies on abortion in 2014, which found that induced abortion is significantly associated with an increased risk of breast cancer – by as much as 44 per cent after one induced abortion.
And the risk of breast cancer increases even more as the number of abortions increases – at least two induced abortions raised the risk by 76 per cent and more than two induced abortions nearly doubled the risk compared to women with zero previous abortions.
This meta-analysis, by Huang et al, was published in the internationally recognised peer-reviewed journal, Cancer Causes and Control. But, unlike the EFC study which was published in the same year, it escaped the notice of the British media and journals (or perhaps was deliberately ignored?).
The findings of Huang’s meta-analysis are consistent with the first systematic review of this link by Brind et al, published in the British Medical Journal in 1996. Huang himself notes the consistency between both their findings in his report.
However, the findings by Brind did not fit with the RCOG claims in 2011 of no association. So in their 2011 report, the RCOG disregards his research. But interestingly, the RCOG was not always so dismissive. In their 1997 and 2001 versions of the ‘Guideline on the Care of Women Requesting Induced Abortion’, they admitted that: ‘The Brind paper had no major methodological shortcomings and could not be disregarded.’
So there appears to be some historical revisionism going on by the RCOG.
While ignoring Brind, the RCOG put great weight on another major meta-analysis, which had findings with which it concurs: Beral et al from 2004. Beral’s analysis indicated that abortion does not increase the risk of breast cancer, and is now one of the primary papers cited as evidence that there is no causal link.
Without going into the details of these meta-analyses, we thus have two of the three meta-analyses showing an association, and one of these is recent (Huang).
Add to this the findings of a link in 51 of more than 70 individual scientific papers on the matter published to date. So it is simply not justified to claim that evidence for a link is non-existent and ‘misinformed’. Just as an example: Two studies published since the 2011 RCOG report (2012 and 2015) find that Mexican women with a history of abortion have more than triple the risk of breast cancer.
However, it is research in China, India and Bangladesh that is some of the most revealing and I shall explore those in another blog.
Clearly, I have a particular ideology on abortion, that I do not hide. But so does the RCOG, whose members are knee-deep in abortion, and yet dismiss any evidence of a link and do not admit their vested interests. (We don’t know how many abortions their president, Lesley Regan, has personally performed in 30 years as a practising gynaecologist, but it would be interesting to know).
I simply ask that ALL the evidence is put on the table, not just one side, because women have a right to know that there is an ongoing debate on the ABC (Abortion and Breast Cancer) link, and that the matter is not settled.
Tomorrow, Philippa Taylor tells what must be done to give women a choice.
