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Dr Odile Bagot (Gynecologist-obstetrician)
Medical validation:
March 23, 2023
According to a new study, women using hormonal contraception have a slightly increased risk of breast cancer. Update on the question with Dr. Bagot, gynecologist.
This is reassuring news for women. A new study published in the journal Plos Medecine reveals that women using hormonal contraception – regardless of delivery method or formula used – have an increased risk of developing breast cancer.
Contraception and breast cancer: an increased risk of about 20% to 30%
According to the researchers, the finding is clear: all forms of hormonal contraception (pill, IUD, implant or injection), including methods containing only a progestogen, lead to a slightly increased risk of breast cancer in women – from about 20% to 30%.
This percentage, to say the least worrying, would be similar to that obtained during previous work. It was calculated using data from just under 10,000 women under 50 who developed breast cancer between 1996 and 2017 in the UK.
But in an attempt to better understand these results, the scientists wanted to calculate the number of “additional breast cancer cases caused“.
Result ? If hormonal contraception is taken for five years between the ages of 16 and 20, the number of women developing breast cancer out of 100,000 will be eight.
If this contraception is taken later, between the ages of 35 and 39, this would represent 265 additional cases of breast cancer out of 100,000 women.
Results that contrast with the study of Dr. Marc Espié, an oncologist specializing in breast cancer. This indeed showed a moderate increase in the risk of breast cancer in women using estrogen-progestogen contraception in premenopause.
Contraception: the risk-benefit balance to be taken into account
If, according to the study’s co-author, Professor Gillian Reeves, “no one wants to hear that something they take will increase their risk of breast cancer“it’s a risk”very small in terms of absolute risk“, she said at a press conference.
Indeed, the overall risk-benefit balance must be taken into account.
Oral contraceptives not only control pregnancies, but also ensure “a fairly significant and long-term protection against other cancers in women, such as endometrial ovarian cancer“, recalls Gillian Reeves.
Moreover, as soon as contraception is stopped, the risk of breast cancer decreases in the years that follow.
A study to be taken with hindsight, according to Dr. Bagot.
“There is often a bias in this type of study. Indeed, the later women have children, the longer they take this contraception and the more they present an increased risk of breast cancer. Conversely, women who stop this contraceptive method young have a lower risk of breast cancer..”
Another important point:Combined estrogen-progestogen methods reduce the risk of ovarian cancer and endometrium“, affirms the expert. The IUD with progesterone would avoid in particular “endometrial thickening“and therefore the occurrence of this cancer.