The link between oestrogen exposure and breast cancer isn’t a new finding, and it has been known for some time that older forms of hormonal contraception based predominantly on oestrogen can elevate breast cancer risk, but with the introduction of more progesterone based hormonal contraception methods such as the progesterone only pill, the contraceptive injection and the IUD, there was hope that breast cancer risk would decrease. A study published this week in The New England Journal of Medicine, however, has revealed that women who are either currently using such hormonal contraceptive methods, or who have recently used them, were 20 per cent more likely to develop breast cancer than women who did not use them.
The study focused on data from 1.8 million Danish women aged between 15-49 monitored over a period of eleven years, finding that women who used hormonal contraceptives for a period of over ten years had around a 40 per cent increased risk of developing breast cancer overall, while using hormonal contraception for a year or less reduced this risk to 10 per cent. For women using hormonal contraceptives for less than five years, any associated breast cancer risk showed a marked decrease after discontinuation of use. In terms of comparison between hormonal contraceptive methods, women using the progesterone only IUD were shown to have a slightly elevated risk overall- these women were 21 per cent more likely to develop breast cancer.
While these results may seem stark and shocking, hormonal contraceptive methods have also been linked to a decreased risk of ovarian, colon and womb cancers , and breast cancer cases amongst hormonal contraceptive users remain relatively low- for every 7,690 women taking the pill every year, one woman will be diagnosed with breast cancer. That’s not to mention the fact that such contraceptive methods also put women in control of their own fertility and prevent unwanted pregnancies. Given the large sample size of the Danish study however, and the fact that hormonal contraceptive use is widespread around the world (one in four UK women take the contraceptive pill), the need for safer hormonal contraceptive methods can’t be understated. It’s time we treated women’s healthcare as a priority, not a work in progress.