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Cervical cancer risk reduces after stopping the birth control pill

2007-11-12 09:25

Birth Control Pills and Cervical Cancer

Women taking the combined oral contraceptive pill are at an increased risk of cervical cancer but this risk starts falling soon after the pill is stopped - according to research published in the Lancet today.

The Cancer Research UK study shows that by ten years after last using the pill the extra cervical cancer risk has disappeared.

The study confirms previous research linking the pill with an increased risk of cervical cancer and reveals for the first time that this risk falls after pill use stops.

Women currently using the pill and who have been using it for at least five years are at nearly twice the risk of cervical cancer compared with women who have never used the pill. Cases of cervical cancer peak in woman in their 30s and there is only a small overall effect on the lifetime risk of developing cervical cancer from use of the pill in young women.

Cervical cancer risk for women up to the age of 50 in developed countries such as the UK who have never used the pill is 3.8 in 1,000. This increases to 4.0 per 1000 in women who use the pill for 5 years, and to 4.5 per 1000 for those who take the pill for 10 years.

Researchers looked at 24 separate studies of more than 52,000 women from 26 countries worldwide. Previous research has also shown an increase in breast cancer risk but a decrease in ovarian and womb cancer in women who take the pill.

Dr Jane Green, lead researcher based at Cancer Research UK's epidemiology unit at the University of Oxford, said: "This study confirms that women who are taking the pill have a small increased risk of cervical cancer. But this increased risk begins to drop soon after women stop taking the pill and after 10 years risk has returned to normal levels.

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"The pill remains one of the most effective forms of contraception, and in the long term the small increases in risk for cervical and breast cancers are outweighed by reduced risks for ovarian and womb cancer."

Dr Lesley Walker, Cancer Research UK's director of information, said: "The link between the contraceptive pill and cervical cancer has been known for some time. This study helps us to quantify the increased risk and to understand how long the risk persists.

"Cervical cancer can be largely prevented by going for regular smear tests so it's vital that all women go for screening when they are invited. It is important for women to weigh up the risks and benefits of taking the pill for themselves and to speak to their doctor if they are concerned. In future we hope that many more cases of cervical cancer will be prevented as a result of the recently-announced HPV vaccination programme."

For media enquiries contact the Cancer Research UK press office on 020 7061 8300, or the out of hours duty press officer on 07050 264059.

The Lancet, vol 370, pp 1609-1621.

The study on cervical cancer and birth control pills was jointly funded by WHO, IARC and Cancer Research UK.

  • The combined Pill. This is by far the most common type of oral contraceptive and consists of two female hormones - oestrogen and progestagen.

  • HPV vaccination programme: October, 2007, the Government announced that girls aged 12-13 will be routinely vaccinated against cervical cancer, starting from September 2008. There will also be a two-year catch up programme starting in Autumn 2009, for girls up to 18 years. Studies have shown that each of the two vaccines available are 100 per cent effective against the HPV strains that it targets. Both target HPV types 16 and 18: these are responsible for around 70 per cent of cervical cancers. So the current vaccines have the potential to prevent up to 7 out of 10 cases of cervical cancer. The highly successful and comprehensive cervical screening programme will continue as the available vaccines do not protect against all cancer-causing types of HPV and it will take several decades before their benefits are seen.
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