Contraceptive Pill

Last week, the media was full of news stories proclaiming that the contraceptive Pill actually protects against cancer. Indeed, it would have been really hard to avoid seeing the story, with coverage on the BBC, and pretty much every single national newspaper.

The safety of the Pill has been a source of controversy for some time. Large studies, including some funded by Cancer Research UK, have shown that while women are taking the Pill, they have higher risk of some cancers but lower risk of others. The big question is: overall, does it do more good than harm? And the answer from this latest study is a resounding yes. Let’s take a look at the results in more detail.

The study started way back in 1968, when scientists from the Royal College of General Practitioners recruited 46,000 women.Half were on the Pill, half weren’t, and all of them were healthy. Over the next three decades, the researchers noted which of them developed cancer and how this related to their use of the Pill.

Here’s what they found:

  • Women who took the Pill had a 12% lower risk of cancer overall.
    They had a 42% lower risk of womb cancer, 46% lower risk of ovarian cancer and 28% lower risk of bowel cancer. The longer women stayed on the pill, the lower their risk of ovarian and womb cancers.
  • They had a slightly higher risk of cervical cancer but this was not ‘significant’. That means that the researchers can’t be sure that this increased risk was not down to chance.
  • They had neither higher nor lower risks of breast cancer. Other large studies have found that the Pill slightly increases the risk of breast cancer. It’s unclear why this study did not, but that suggests that if there is and increased risk, it’s a very small one.
  • If they stayed on the Pill for over 8 years, they had a 22% higher risk of cancer overall, and that’s mainly because their risk of cervical cancer goes up. In reality, most women stop taking the Pill well before that. For example, those in the study stayed on the Pill for an average of about 4 years.

While no one would recommend that women take the Pill explicitly to reduce their risk of cancer, this study should be reassuring to the millions of women who have used the Pill since its introduction. It provides strong evidence that, in the short term at least, taking the Pill is safe.

Based on other large studies, we’ve known for some time that the Pill could increase the risk of cervical cancer and, to a lesser extent, breast cancer. But we have to put these increased risks in perspective.

At the age when most women take the Pill, their risk of breast cancer is very low (at age 30, it’s about 1 in 1900). So the Pill would only slightly increase what is already a very small risk.

Cervical cancer is more common in younger women, but in this case, the UK has an excellent national screening programme that can prevent the disease by detecting abnormal changes in the cells of the cervix before they turn into full-blown cancers.

The Pill’s benefits are also more persistent than its risks. If you stop taking the Pill, the increased risk of cervical cancer (and possibly breast cancer) dwindle away in about 10 years.

But the reduced risk of ovarian and womb cancer stick around for at least 15. This means that in later life when the majority of cancers are most common, the increased risks are likely to be gone, but the protective effects might still be around.

It’s a different situation for ovarian cancer, which has no screening programme and is typically detected at a late stage. As a result, the five-year survival rate for ovarian cancer is very low. If the Pill halves the risk of this cancer developing in the first place, that’s a very significant significant benefit.

Finally, amid all the talk about cancer, people often forget the Pill’s main purpose – it’s a contraceptive and a very good one. If taken correctly, it’s 99.7% effective at preventing unwanted pregnancies and that benefit must also be weighed against any potential risks.