Busting Breast Cancer Myths

Roslyn Phillips

Journalist Tory Shepherd wrote a column in The Advertiser (30/10/13) entitled: “Let’s bust these breast cancer risks wide open”. I couldn’t agree more! Tory went on: “All the pink, the fundraiser cupcakes and celebrity appearances have managed to make women hyper-aware about the existence of breast cancer, but blissfully ignorant of many of the facts of the disease.”

Right again. It seems a recent Newspoll survey of 1200 Australian women found that many of them think food additives, underarm antiperspirants and stress are major breast cancer risk factors. “Horsetwaddle,” Tory says – noting that three significant risks (apart from having the wrong gender, age and genes) are being fat, not exercising, and drinking alcohol. But Tory failed to explain that the underlying factor in both fat and alcohol risks is overexposure to the female hormone oestrogen.

The oestrogen factor Being fat is a risk because fat cells secrete oestrogen. Drinking alcohol, even just one or two standard drinks daily, is a risk – because alcohol interferes with the breakdown of oestrogen in the liver. And the oestrogen risk is not confined to obesity and alcohol. Hormonal contraception and hormone replacement therapy are based on chemical compounds similar to oestrogen. Used long-term, they can predispose women to breast cancer – particularly so when the pill is used from the early teen years.

But there’s another oestrogen risk as well: an interrupted pregnancy. During pregnancy, oestrogen levels soar, making the breasts grow. One reference I consulted said that a woman is exposed to more oestrogen during pregnancy than her total exposure during the rest of her non-pregnant life. In a first pregnancy, all breast lobules are immature and vulnerable to cancer. When they multiply under the influence of oestrogen, there is a greater chance that one or more lobules will later turn cancerous. This risk is greatly lowered by the end of the pregnancy, when the lobules mature to become cancer-resistant milk-producers. Having a baby before the age of 30, and breast feeding the baby, are protective factors for breast cancer.

Full-term pregnancy protects But if an abortion is performed before the last two months of pregnancy, the mother is left at increased risk of cancer because the maturing process has not occurred. The most dangerous abortions are those performed on a first pregnancy, years before the mother gives birth to a full-term baby. Teenage girls who abort their first pregnancy, then take hormonal contraception for an extended time, are at greater risk than many other women.

I didn’t expect Tory to mention abortion in her article about breast cancer risks. I had emailed her some years ago when she was the Advertiser health editor. Yet another study had been published, showing that abortion is a breast cancer risk. I sent her a copy and asked why she had not reported it. “Our national people didn’t send it through,” she said. “I don’t know why.”

I pointed out that she could write about the research findings now she had seen them. But Tory said no. The study was published the week before, so it was old news!

More recent studies with similar findings must have been “old news” too. There has not been so much as a whisper in the Australian mainstream media – until this year. On 15 August 2013, Family Voice Australia circulated a media release about a new study by Dr Suraiya Jabeen and five others from the National Institute of Cancer Research and Hospital in Dhaka, Bangladesh.(1) The study matched 262 women with breast cancer with 262 women of similar age and background without breast cancer, and looked at factors that may be linked with the disease.

Bangladesh is a poor, Muslim country. Most Bangladeshi women are slim, have several children at a young age, and breast feed them. They drink little if any alcohol. Tory Shepherd would not be surprised to learn that Bangladeshi breast cancer rates have been historically low.

But that is fast changing. In the last ten years or so, breast cancer rates in Asian nations have been on the rise, (2) and in younger women than ever before, despite low rates of obesity and alcohol consumption. The Jabeen study found that women who have a family history of breast cancer, or smoke, or are overweight, are more likely than others to suffer breast cancer in mid-life. But Jabeen found that the biggest risk of all was in women who had previously had an abortion – a huge odds ratio of 20:62.

Of the 262 women with breast cancer, 88% had previously had an abortion. Of the 262 women in the control group without breast cancer, only 27% had previously had an abortion. And amazingly, this study was reported on ABC radio. But not the way you might think.

An inconvenient truth ABC radio studios in at least two Australian states called in science guru Dr Karl Kruszelnicki to comment on our media release. He promptly damned it. “The Dhaka research was not published in a peer-reviewed journal!” he thundered, itemising a number of errors and inconsistencies in the Jabeen study. But these shortcomings could not alter the fact that far more of the Bangladeshi women with breast cancer had a history of abortion than those in the cancerfree control group. For Dr Karl, this truth was apparently inconvenient.

He also ignored the clear statement in the FamilyVoice media release: “The breast cancer-abortion link is especially pronounced in this study, but is generally in line with the great majority of similar studies worldwide that have also found such a link. Of 68 studies in this area since 1957, 53 have shown a connection between abortion and breast cancer. Only 15 have not found a link.”

Indeed, in May 2013, not long before the publication of the Bangladeshi study, an Indian study by Dr Ramchandra Kamath et al in a peer-reviewed journal (3) found an abortion- breast cancer risk with an odds ratio of 6.38 – higher than any Western breast cancer study.

Western studies find different risk ratios Why would the abortion risk appear to be higher in some countries than others? The answer lies in differences in lifestyle and culture.Western women have multiple risk factors including high rates of obesity, hormonal contraception, binge-drinking and delayed or non-childbearing, all of which may confound research findings. Asian women with low rates of these factors, but high rates of abortion, are likely to produce much higher odds ratios for the abortion risk than for Western women.

I emailed Dr Jabeen, who replied (in part, emphasis added): In Bangladesh, infrastructure for health services is very good. Domiciliary health services are available at door steps of remote areas also. Infant Mortality & Maternal mortality are also going down. Family planning services are also good. Even then, most of the women prefer induced abortion as family spacing method. Here, these respondents could give their abortion history correctly! So, risk might have increased from other breast cancer studies.

This account explains the very high overall abortion rate in the study participants – much higher than the rate in Australia. The lack of social stigma associated with abortion in Bangladesh means that women’s reports are likely to be accurate. But there is another factor in the high breast cancer rate in aborted Dhaka women – their cultural preference for boys, leading to high rates of abortion for unborn female babies. Such abortions can only be performed halfway through the pregnancy, when an ultrasound scan can determine the sex of the foetus. At 20 weeks, the mother will have already been exposed to much higher oestrogen levels, for much longer, than Western women whose terminations mostly occur before 12 weeks of pregnancy. The breast cancer risk following a late sex-selection abortion is high.

Tory Shepherd has made it very clear in her many newspaper columns that she is “pro-choice”. Yet women deserve to know all the facts before making their choice. Let’s bust wide open the myth that abortion is not a breast cancer risk!

1. Jabeen, S et al, 2013, “Breast cancer and some epidemiological factors: a hospital based study”, Journal of Dhaka Medical College; 22(1), 61-66.
2. E.g. Kountaya Sinha, “Breast cancer cases on the rise”, The Times of India, 26/2/11: Kelly Chung Dawson, “Breast cancer on the rise in China”, Asia News Network, 24/10/13.
3. Ramchandra Kamath et al, Indian J Community Medicine, 2013, Vol 38 (2), 95-99.