A new study carried out by researchers from the Cancer Epidemiology Unit of the Oxford University shows that the use of oral hormonal contraceptives of progestogen (also known as POPs or mini pills) is associated with a risk of 20 to 30 percent higher of having breast cancer.
The results have been published in PLOS Medicine. Previous studies had already shown that the use of combined contraceptiveswhich in addition to this group of hormones have estrogensis associated with a small increase in the risk of developing this disease and that this decreases after stopping taking it.
Nearly ninety million women they are used all over the world. As they are not advisable while breastfeeding a baby, mini-pills were developed in the 1970s.
Three years before
In this latest study, funded by the Cancer Research UK charity, researchers analyzed data from 9,498 women who developed breast cancer between the ages of 20 and 49 and 18,171 women who had not. Both 44% of the former and 39% of the latter had been prescribed the pill an average of three years before diagnosis. Approximately half of the cases were progestin-only.
The data, collected by the Clinical Practice Research Datalink (CPRD), were used to calculate the strength of the association between the use of each type of contraceptive hormonal and the risk of neoplasia. These calculations were then adjusted to account for established risk factors such as body mass index (BMI), the number of deliveries recorded and the time elapsed since the last.
The researchers combined the results of the CPRD with those of other previously published studies to calculate the absolute excess risk, that is, the additional number of women who would be expected to develop breast cancer in those using oral contraceptives compared to those using oral contraceptives. that they didn’t.
According to Kirstin Pirie, one of the study’s lead authors, the results suggest that the use of progestin-only contraceptives is associated with a slightly increased risk of this disease, similar to that associated with pills that also contain estrogen. “Since a person’s underlying risk of developing a breast tumor increases with age, the absolute excess risk associated with either type of oral contraceptive will be lower in women who use them at younger ages,” he says. In any case, “these excessive risks must be considered in the context of the well-established benefits of pill use in women’s reproductive years,” she adds.
Short term
The researchers also note that while these results provide evidence for short-term associations between hormonal contraceptives and breast cancer risk, they do not provide information about longer-term associations, or the impact of total duration of use. use, since there is not enough information for it.
Use of progestogen-only contraceptives has increased substantially in recent years, at least in England. In fact, in 2020 almost as many were prescribed in this country as combined pills, although it is true that the information on their association with cancer risk was limited, they point out from Oxford.
