The use of an intrauterine device halves the risk of developing cervical cancer, according to the largest ever epidemiological study of the association, published online in The Lancet Oncology.
An analysis of individual data from two large international studies involving over 20,000 women found ‘a strong inverse association between IUD use and cervical cancer risk’ and a 45% reduction in the risk compared with women who were not fitted with a device.
Some 2,205 women with cervical cancer were compared with 2,214 matched controls without cervical cancer and 15,272 healthy women who were included in a survey to test for the presence of the HPV virus in cervical cells.
After adjusting for relevant covariates, including cervical HPV DNA and number of previous cervical smear tests, every use of IUDs and cervical cancer was associated with an odds ratio for cervical cancer of 0.55.
No association was found between IUD use and detection of cervical HPV DNA among women without cervical cancer.
Dr Xavier Castellsagué, a researcher at the Cancer Epidemiological Research Program in Catalonia, Spain, concluded: ‘The associations found in our study strongly suggest that IUD use does not modify the likelihood of prevalent HPV infection, but might affect the likelihood of HPV progression to cervical cancer. IUD use could possibly be regarded as a protective cofactor in cervical carcinogenesis.’
The Lancet Oncology 2011, online 13 September.