Right to know the risks

Roslyn Phillips

September 05, 2006

http://www.news.com.au/couriermail/story/0,23739,20351240-27197,00.html

MY MOTHER-in-law never believed that smoking might lead to lung cancer or strokes.

When studies began showing the health risks of smoking, my mother-in-law preferred to believe other studies which were less clear.

Twenty years later, smoking contributed to her death.

And with the controversy over health risks with the Pill, HRT and abortion, I have a sad sense of deja vu.

Paul Syvret (Perspectives, Aug 29) has raged against Melbourne journalist and scientist Babette Francis, who suggested reproductive history might be a factor in the recent cluster of breast cancer cases among ABC employees at Toowong.

Over four decades, the incidence of male breast cancer has remained very low and stable in Australia, while female breast cancer has almost doubled. The highest rate is in affluent ACT and the lowest in the Northern Territory – which also has the highest birth rate. Is Francis right?

We know that women who begin menstruating early or reach menopause late are at higher risk of breast cancer. They are exposed to an excess of the female hormone estrogen through a higher than normal number of menstrual cycles.

Women who have no children or who have delayed having them until after 30 are also at higher risk of breast cancer because they miss out on the protection given by full-term pregnancy and breast feeding.

Teenage girls who take the Pill for many years – possibly to control period pain – are also at significantly higher risk of breast cancer, because the Pill's synthetic estrogen and progesterone hormones are carcinogenic. Long-term hormone replacement therapy is a breast cancer risk for the same reason.

Estrogen levels soar by 2000 per cent during the first trimester of pregnancy, making the breast lobules grow. These stage 1 and 2 lobules are vulnerable to cancer.

It is not until the last eight weeks of pregnancy that they mature to stage 4 and become cancer-resistant, ready for lactation. Aborting a first pregnancy leaves a woman with a much higher number of cancer-vulnerable lobules. Cancers may take up to 20 years to become a detectable lump.

The first study to show a link between abortion and breast cancer was in Japan in 1957. Since then at least 27 out of 37 studies worldwide have also found a link.

Even the 1997 Melbye study of 1.5 million Danish women, when corrected for its serious methodological flaws, shows a significant increased risk of breast cancer among women who have had an abortion, with a higher risk for late abortions or very premature births.

Beral's 2004 meta-analysis in The Lancet, which found no link, has been criticised for its highly biased selectivity.

The good news is that new treatment for breast cancer is saving many lives, especially if the cancer is detected early.

If women know they are at increased risk, they are more likely to have mammograms.

Knowledge is power – and women, whatever their chosen lifestyle, have a right to know the possible risks involved.

Roslyn Phillips, BSc Dip Ed, is research officer for Festival of Light Australia