Oral contraceptive pill offers long-term protection against ovarian cancer

Writing in The Lancet the Collaborative Group on Epidemiological Studies of Ovarian Cancer say that the use of the oral contraceptive pill over the past 50 years may have prevented some 200 000 ovarian cancers and over 100 000 deaths from the disease. They go on to say that over the next few decades the number of cancers prevented will rise to at least 30 000 per year.

The study focused on the long-term effects of pill use on ovarian cancer incidence and examined 45 epidemiological studies in 21 countries. This provided individual data for 23257 women with ovarian cancer (cases) and 87303 without ovarian cancer (controls).

Around 31% of the women in the cancer group and 37% of the women in the control group had used the oral contraceptive pill for an average of 4.5 and 5 years respectively. The longer the women used the pill the greater the reduction in risk of cancer, persisting for about 30 years, although the effect was attenuated over time.