The Pill: no increased cancer risk
Publication Date:20/09/2007
A big study has found that taking the contraceptive pill doesn't increase the risk of getting cancer, for most women. The pill may even cut the risk of cancer. But this may not be true for women who use it for more than eight years.
What do we know already?
Millions of women have used the contraceptive pill to prevent pregnancy since it was introduced in the 1960s. But there has been a lot of discussion about whether the hormones in the pill can increase a woman's risk of getting cancer.
The confusion is because the contraceptive pill increases the risk of some cancers, but decreases the risk of others. For example, the pill slightly increases the risk of getting cervical cancer, but cuts the risk of cancer of the womb or ovaries. So it's hard to know whether the overall risk of cancer is higher or lower with the pill.
This study followed almost 50,000 British women for up to 36 years, to see if the overall risk of getting cancer was bigger or smaller for women who did or did not use the pill.
What does the new study say?
The study found that, overall, women who took the contraceptive pill had no higher risk of getting cancer than women who never took it. In fact, they might have a slightly smaller risk of getting some types of cancer. These were bowel cancer, womb cancer and ovarian cancer.
But the results were different for the women who took contraceptive pills for more than 8 years. They had a slightly increased risk of getting cancer.
Tell me more about the study's findings
The figures were collected from women's GPs. They showed that, on average, there were 35 cancers every year for every 10,000 women who took the pill. This compared to 39 cancers for every 10,000 women who never took the pill. So women were 12 percent less likely to get cancer, if they took the pill.
However, women who had used the pill for more than eight years might have a slightly higher overall risk of cancer than women who had never used it. This was partly because they had an increased risk of cervical cancer. These women still had a lower risk of womb and ovarian cancer.
And the risk of breast cancer, which is the most common cancer affecting women in the UK, was no higher for any women who used the pill, however long they had used it.
Where does the study come from?
The study was carried out by researchers at the University of Aberdeen, in Scotland. They used figures collected by the UK's Royal College of General Practitioners. The study was published in the UK medical journal, the BMJ.
How reliable are the findings?
This is a very big study, comparing large groups of women. This means the results are more likely to be reliable. However, there are some problems.
Because it was so long, more than half of the women in the study left before it was finished. This was mainly because they moved out of their GPs' area. The researchers checked on about three-quarters of the women through national registers of cancers, but some women who developed cancer may not have been picked up.
Also, lots of things, including diet, exercise and family history, affect cancer. The study couldn't make allowances for all these things. For example, smoking is a big cause of cancer, but women were only asked whether they smoked at the start of the study. If women started smoking during the study this could affect the results.
Finally, the information about women who had used the pill for more than eight years may be less reliable than the overall figures. That's because less than one-quarter of women taking the pill had used it for this long. So the results are based on much smaller numbers.
What does this mean for me?
The study started in 1968, so most of the women in the study will now be in their 60s or 70s. If you are around this age, and used the pill when you were younger, you may find the study reassuring. It shows that, for most women, taking the pill did not increase their risk of cancer. You may have a lower risk of cancer than if you had not taken it.
If you are a younger woman taking the contraceptive pill now, it's harder to make comparisons. Contraceptive pills have changed a lot since they were introduced in the 1960s. The types of pill used by women in the study are quite different to the modern types and have much lower doses of hormones.
Also, the women in the study were around 29 when the study started, and used the pill on average for only three to four years. Women today may start using it younger, and use it for longer. So we can't be sure that all the findings will apply to women taking the pill today.
The contraceptive pill has other risks and benefits, apart from its effect on cancer risk. If you are considering taking the contraceptive pill, you will need to weigh up all these factors. Your GP or family planning clinic can help you decide what type of contraception is best for you.
What should I do now?
There's no need to take any action as a result of this study. If you have questions about your choice of contraceptive, talk to your GP or family planning clinic at your next routine appointment.
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© BMJ Publishing Group Limited ("BMJ Group") 2007. All rights reserved
This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
