Progestogen-only pill carries SAME 20% heightened risk of breast cancer as traditional version

A newer type of birth control pill that has exploded in popularity in recent years carries the same breast cancer risk compared to a more traditional version, a study suggests.

Historically, most women have preferred a ‘combined’ contraceptive pill containing two hormones, estrogen and progestogen.

In recent decades, however, more and more have opted for a progestin-only pill – with prescriptions for the two different types now aligned.

Now a new study reveals that the progestin-only pill carries the same increased risk of breast cancer as its older equivalent.

Previous research has shown that women who use the combined contraceptive pill, or who have recently stopped taking it, are about 20 percent more likely to get breast cancer compared to those who don’t take it.

A team from the University of Oxford analyzed data from more than 9,000 women who developed invasive breast cancer aged 20 to 49, and 18,000 similar women who did not develop the disease.

Analysis revealed that those who used the newer progestin-only pill or had recently stopped taking it also had a 20 to 30 percent increased risk of breast cancer.

However, this effect seemed to diminish once women stopped using it, with no additional risk 10 years after they stopped using the contraceptives.

Their findings also applied to both types of hormonal contraceptive, 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 associated risks of 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 don’t really see any indication here that women need to necessarily change what they’re doing.

“Yes, there is an increase here, and yes, no one wants to hear that something they are taking increases their risk of breast cancer by 25%.

‘The main purpose of this research was actually to fill a gap in our knowledge.

‘We have known for years that combined oral contraceptives, which women have used for decades, also have an effect on the risk of breast cancer, a small increase in risk that is transient.

“We weren’t quite sure what the corresponding effect of these progestogen-only contraceptives would be.

“What we’ve shown is that they’re exactly the same in terms of breast cancer risk. They seem to have a very similar effect to the other contraceptives, and the effect that we’ve known for many years.”

Kirstin Pirie, 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 small increase in breast cancer risk, similar to associated with the use of combined oral contraceptives.

‘As 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 smaller in women who use it at a younger age.

“However, these additional risks should be seen in the context of the established benefits of contraceptive use in women’s reproductive years.”

Commenting on the study, Dr Kotryna Temcinaite, head of research communications at Breast Cancer Now, said: ‘This research suggests that there is a small increased risk of developing breast cancer for women while taking a newer progestogen-only or stopping soon after. contraceptive.

‘The risk is about the same as with the older combined pill with estrogen and progestogen, which we have known for some time. For both types of contraceptives, if you stop using them, this extra risk of breast cancer decreases over time.

‘The study did not look at which hormonal contraceptives the women had used in the past or how long they had used the progestogen-only contraceptive.

“It also didn’t matter whether a family history of the disease contributed to their risk level.” So more work is needed to help us fully understand the impact of using this type of birth control.

Breast cancer is rare in young women. A slight increase in risk during the time a woman takes 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 in London, added that the results are ‘reassuring because the effect is modest’.

NHS figures in 2008 revealed that there were just under six million prescriptions for combined hormonal contraceptives in England, compared to less than two million for the progestin-only pill.

However, by 2020, the gap had closed and prescriptions for both were around 3.2 million.