Contraceptive pill likely cause for 20 percent drop in ovarian cancer rates

Cancer Research UKSep 8 2009

Ovarian cancer rates have fallen by almost 20 per cent in a decade, according to Cancer Research UK today (Wednesday).

Rates for women in their 50s and early 60s are nearly 20 per cent lower than they were in 1998.

And for women under 50* rates are 14 per cent lower than they were at their peak in 1997.

This dramatic drop is likely to be due to women taking the contraceptive Pill, which can protect against the disease.

Decreasing use of hormone replacement therapy (HRT) could also have contributed to the fall in rates.

Dr Lesley Walker, Cancer Research UK's director of cancer information, said: "The trend in the number of women getting ovarian cancer reversed suddenly around ten years ago, and these latest statistics make it clear that rates are continuing to fall steadily. This is good news for women. We know from Cancer Research UK studies that taking the Pill for more than 15 years halves the risk of ovarian cancer.

"We can't be sure that the drop in ovarian cancer rates is solely due to the Pill, but it has played an important part."

Rates of women getting ovarian cancer had been rising steadily since records began in the 1970s.

For women under 50, rates peaked in 1997, with almost 11 women in every 100,000 being diagnosed with the disease.

For women between 50 and 64, rates peaked at nearly 47 women in every 100,000 in 1998.

The latest figures revealed today show this figure has dropped to around 9 in every 100,000 women under 50 and around 38 in women between 50 and 64.

The number of women taking the Pill has been increasing since it became widely available in the 1970s, and the drop in ovarian cancer rates could be a delayed effect of this. The reduction in the number of women taking hormone replacement therapy (HRT) since 2000 when its cancer risks became clear may also have contributed to this drop**.

When hormone levels are increased, as they are with HRT, they can make cells grow and divide uncontrollably. Damaged cells usually die, but when they don't cancer can develop. But with the contraceptive Pill, high levels of hormones prevent ovulation and slow cell division. This can reduce the risk of cancer.

Dr Walker added: "These new figures add to the evidence that the protective effect of the Pill is strong and it will be interesting to see if this trend continues as women make choices about taking the Pill and HRT over the next few years.

"Any woman with concerns or questions about taking the contraceptive Pill should discuss them with her GP or local Family Planning Clinic. And if you are worried about HRT and ovarian cancer, you should speak to your GP, who can discuss the risks and benefits in your individual situation."