Today women have a multitude of options when choosing a hormonal contraceptive method. Pills, patches, implants, and injections: The various forms of hormonal birth control have different formulations and doses of estrogen, progestin, or a mixture of both. Which could make us think that they may have an unequal influence on the risk of breast cancer. However, a new study published in Plos Medicine on Tuesday found that most forms of hormonal birth control, regardless of their formulation, appear to confer an increased risk of breast cancer.
The study, published in the journal Plos Medicine, is the first to establish a link between all forms of hormonal contraception and breast cancer. “It’s kind of interesting and strange that all these different hormonal contraceptives with and without estrogen have increased risk so close to one another,” said Carolyn Westhoff, a contraceptives researcher at Columbia University who didn’t work on the study.
Which birth control methods increase the risk of breast cancer?
Hormonal contraceptives may contain estrogen and progestin or progestin-only and work by preventing the release of eggs from the ovaries, thickening the cervical mucus, and thinning the endometrium. However, these hormones are also important for the formation and growth of most breast cancersso researchers have studied how hormonal contraceptives might alter this risk.
For their realization, the scientists analyzed the records of the National Health Service of the United Kingdom (NHS, for its acronym in English) of 10,000 women under the age of 50 who were diagnosed with breast cancer between 1996 and 2017. Their history of contraceptive prescriptions was compared with a control group of 18,000 women, of the same ages and who had undergone the same medical procedures, who had not been diagnosed with breast cancer.
As a result of data analysis, it was found that all forms of hormonal contraceptionincluding the pill, implant, or intrauterine device (IUD), aincrease the risk of breast cancer between 23% and 32%. In addition, it is estimated that for every 100,000 35-year-old women who take hormonal contraceptives over a five-year period, 265 more will develop breast cancer compared to those who do not use hormonal contraceptives. For women ages 16 to 20, eight more would get breast cancer for every 100,000 women using hormonal birth control.
Is the new pill or the traditional one better?
The new pill, whose only ingredient is progestin, carries the same risk of breast cancer as the traditional pill, which has been available in the UK since 1961 and has been linked to an increased risk of breast cancer, the research found. of cancer in 1996.
However, experts noted that the probability of developing breast cancer in young women is very low and seems to decrease when women stop using such contraceptive methods. “These increases in breast cancer risk need to be seen in the context of the many benefits of taking hormonal contraceptives,” said Gillian Reeves, lead author of the study and director of the Cancer Epidemiology Unit at the University of Oxford. not only in terms of birth control, but because oral contraceptives provide substantial, long-term protection against other female cancers, such as ovarian cancer and endometrial cancer.”