A new type of birth control pill that has gained popularity in recent years carries the same risk of breast cancer as a more traditional version, a study suggests.
Historically, most women preferred a ‘combined’ contraceptive pill that contains two hormones, estrogen and progestin.
However, in recent decades, more people have opted for a progestogen-only pill, with prescriptions for the two different types now on par.
Now a new study reveals that the progestin-only pill carries the same increased risk of breast cancer as its older equivalent.
Historically, most women preferred a ‘combined’ contraceptive pill that contains two hormones, estrogen and progestin. But now the prescription of the progestin-only pill is on par
Previous research has shown that women who are using, or have recently stopped taking, the combined contraceptive pill have about a 20 percent increased risk of developing breast cancer compared to those who do not take it.
A team at the University of Oxford analyzed data from more than 9,000 women who developed invasive breast cancer between the ages of 20 and 49 and 18,000 similar women who did not develop the disease.
The analysis revealed that those who were taking, or had recently stopped taking, the new progestogen-only pill also had a 20 to 30 percent increased risk of breast cancer.
However, this effect seemed to disappear once the women stopped using them, with no excessive risk 10 years after stopping the contraceptives.
Their findings were also applicable to both types of hormonal birth control taken in any form, be it an injection or an implant.
The team said their research, published in the journal Plos Medicine, helps “fill a gap” in knowledge about the risks associated with taking hormonal contraceptives.
But they said these risks must be weighed against the known benefits of taking them.
Gillian Reeves, professor of statistical epidemiology and director of the Cancer Epidemiology Unit at the University of Oxford, said: “I really don’t see that there’s any indication here to say that women necessarily need to change what they’re doing.”
“Yes, there is an increase here, and yes, no one wants to hear that something they are taking will increase their risk of breast cancer by 25%.
‘The main goal of doing this research was really to fill a gap in our knowledge.
“We have known for many years that combined oral contraceptives, which women have been using for decades, also have an effect on breast cancer risk, a small increase in risk that is transient.
“We weren’t absolutely sure what the corresponding effect of these progestin-only contraceptives would be.
“What we’ve shown is that they’re the same in terms of breast cancer risk, they seem to have a very similar effect to other contraceptives and the effect we’ve known about for many years.”
Kirstin Pirie, a statistical programmer at Oxford Population Health and one of the lead authors, said: “The findings suggest that current or recent use of all types of progestogen-only contraceptives is associated with a slight increase in the risk of breast cancer. , similar to that associated with the use of combined oral contraceptives.
“Since a person’s underlying risk of developing breast cancer increases with age, the absolute excess risk of breast cancer associated with any type of oral contraceptive will be lower in women who use it at younger ages.
“However, these excess risks must be viewed in the context of the well-established benefits of contraceptive use in women’s reproductive years.”
Commenting on the study, Dr. Kotryna Temcinaite, Breast Cancer Now’s head of research communications, said: “This research suggests that there is a small increased risk of developing breast cancer in women while using, or shortly after stopping it, a new medication that contains only progestin”. contraceptive.
“The level of risk is more or less the same as that of the old combined pill containing estrogen and progestin, which we have known about for some time. For both types of birth control, if you stop using them, this additional risk of breast cancer is reduced over time.
A team at the University of Oxford analyzed data from more than 9,000 women who developed invasive breast cancer between the ages of 20 and 49 and 18,000 similar women who did not develop the disease. The analysis revealed that those who were taking, or had recently stopped taking, the new progestogen-only pill also had a 20 to 30 percent increased risk of breast cancer.
“The study did not look at which hormonal contraceptives the women may have used in the past or consider how long they may have been taking the progestogen-only contraceptive.
“It also did not take into account whether a family history of the disease contributed to their level of risk. Therefore, more work is needed to help us fully understand the impact of using this type of contraceptive.
‘Breast cancer is rare in young women. A slight increase in risk during the time a woman is using hormonal contraceptives means that only a small number of additional cases of the disease are diagnosed.’
Professor Stephen Duffy, from the Center for Prevention, Detection and Diagnosis at Queen Mary University of London, added that the results are “reassuring in that the effect is modest.”
Figures from the NHS revealed in 2008 that there were just under six million prescriptions for the combined hormonal contraceptive in England, compared to less than two million for the progestogen-only pill.
However, by 2020, the gap had closed, and prescriptions for both were around 3.2 million.
