Nov. 8, 2007 -- Women who use oral contraceptives have an increased risk of developing cervical cancer, but the riskdrops quickly once the pill is stopped.
Taking oral contraceptives for five or more years was associated with adoubling of cervical cancer risk in the newly published study.
But risk returned to that of never-users within a decade of stopping oralcontraceptives.
The new analysis of data from 24 worldwide studies is one of the mostrigorous examinations of cervical cancer risk in oral contraceptive users everconducted.
Epidemiologist Jane Green, MD, who led the study team, tells WebMD that thefindings should be seen as good news for women who take the pill or have takenit in the past.
The study is reported in the Nov. 10 issue of the journal TheLancet.
"We have known that women on the combined estrogen pill are at increasedrisk [for cervical cancer], she says. "What we haven't known is whathappens after they stop taking the pill. Now we know that the risk starts tofall pretty quickly and has gone away 10 years later."
Cervical Cancer and the Pill
The new analysis of published and previously unpublished data from studiesinvolving more than 16,500 cervical cancer patients and 35,500 women withoutthe disease helps to quantify the risk associated with oral contraceptive useworldwide.
Routine screening for cervical cancer in developed countries like the UnitedStates has led to dramatic reductions in incidence.
For every 1,000 women in more developed countries who use the pill betweenthe ages of 20 and 30, the researchers estimated that less than one extracancer (4.5 instead of 3.8 for never-users) can be expected by the age of50.
In less developed countries, the risk was estimated to be 8.3 cases per1,000 decade-long oral contraceptive users, compared with 7.3 cases for every1,000 never-users of the pill.
The sexually transmitted human papillomavirus (HPV) is a major risk factor forcervical cancer, but having multiple childbirths is also considered a riskfactor for the disease.
Because of this, any discussion of risk related to use of oralcontraceptives must consider whether women end up having fewer babies becausethey take them, says Peter Sasieni, PhD, of London's Wolfson Institute forPreventive Medicine.
Regular Screening Important
And since use of oral contraceptives reduces a woman's risk of developingovarian and endometrial cancer, Sasieni and Green agree thatbenefits probably outweigh the risks for most women.
Both also agree that the new findings show the importance of regularcervical cancer screening for women who take the pill.
"Regular screening is important for all women, but especially for thosetaking oral contraceptives," Sasieni says. "A woman who has regularscreenings can basically forget about the increase in risk."