Currently, breast cancer continues to be the most diagnosed cancer in women in Spain. During the year 2024 alone, it is estimated that there will be 36,395 new cases of this type of cancer, representing around 30% of cancers in women, according to data from the Spanish Society of Medical Oncology (SOME).
Luckily, the advances in diagnosis and treatment of breast cancer have managed to reduce their mortality. We know more and more about a type of cancer usually associated with age, with a certain genetic load, and also related to obesity or the consumption of toxic substances such as alcohol. However, there are other factors to take into account, as is the case with some drugs.
During the past year 2017, the The New England Journal of Medicine published a large observational study where the consumption of combined hormonal contraceptiveswhere estrogens and progestogens are used, being the most modern today. In this study it was suggested that there was a relationship small between the consumption of this type of contraceptives and breast cancer.
Currently combined hormonal contraceptives are on the list of International Cancer Research Center (IARC)dependent on the WHO. In this list we can also find postmenopausal estrogen therapy, and combined estrogen and progestin therapy for menopause.
However, Not all contraceptives are the same.not all use the same types of estrogens and progestogens, and not all contraceptives used today are always combined. In fact, that particular large study did not make clear whether the relationship between contraceptives and breast cancer would also exist for men. progestin monotherapyalso known as “mini pill“.
Thus, during the past year 2023, a new study published in PLOS Medicine wanted to discern if really all the contraceptives, simple or combinedthey should be put in the same bag. To do this, 9,498 breast cancer cases from the United Kingdom were analyzed and compared with a control group of more than 18,000 women.
Let us remember that the progestogen-based hormonal contraceptives They are especially indicated in lactating women, smokers or those at greater risk of suffering from blood clots; This is because, unlike combined contraceptives, they do not contain estrogens, thus reducing the main risk associated with this type of new generation contraceptives, such as thrombotic risk.
Once again, this new study concluded that progestin-containing contraceptives would also be associated with a slight increased risk of suffering breast cancer, of similar magnitude to that detected in combined hormonal contraceptives. And this risk would be independent of the way the contraceptive is consumed: oral, subcutaneous implant or hormonal IUD.
Real risks and benefits of contraceptives
Despite the findings of these studies, the experts call for calm: Most of the studies where a relationship has been found are observational studies, and if said relationship really existed, the increased risk detected has been considered low, and becomes a zero risk after stopping consumption.
As examplethe most recent study would suggest that, among women between 16 and 20 years old, cancer could be detected in 8 out of every 100,000 users, a fact that sounds different from saying that there is “a 25% greater risk” from taking contraceptives. Likewise, between 35 and 39 years old, there would be 265 cases per 100,000 users, something to be expected by experts, given that the risk of this type of cancer increases with age.
Regarding the benefitslet us remember that the new combined contraceptives have been linked to a lower risk of ovarian cancer in young women, even years after taking them, as a study published in the British Medical Journal: Up to 21% of ovarian cancers would have been prevented thanks to combined hormonal contraceptives.
For its part, the United States NIH also suggests that contraceptive use is related to a 30% lower risk of endometrial cancerand between a 15% and 20% lower risk of colon and rectal cancer in women users of these drugs.
