Clinical research Does the pill increase the risk of breast cancer?

The use of any type of hormonal contraceptive may increase the risk of breast cancer, research from the University of Oxford has suggested.

- Andrew Gregory

Although experts have stressed this should not discourage people from taking the pill, the findings have prompted questions. So how concerned should people be?

Why was this study done?

It has been well-known for decades that use of combined oral contraceptives is associated with a small increase in breast cancer risk. But until now there has been limited data about the effect of progestogen-only contraceptives, the use of which has increased substantially over the past decade.

In 2020, there were almost as many prescriptions in England for oral progestogen-only contraceptives as for combined oral contraceptives. Given the increasing use of progestogen-only contraceptives, it is important to understand how their use is associated with breast cancer risk.

What did the researchers find?

They studied 9,498 women aged under 50 diagnosed with breast cancer between 1996 and 2017 to assess the relationship between a woman's recent use of hormonal contraceptives and their risk of breast cancer. They also looked at 18,171 healthy women, who acted as study controls.