IUD use reduces the risk of cervical cancer
MedWire News: The use of an intrauterine device (IUD) does not increase the risk for cervical cancer, research shows.
IUD use was associated with a significantly lower risk for both cervical squamous cell carcinoma and adenocarcinoma, but did not lower the risk for human papillomavirus (HPV) infection.
"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," write Xavier Castellsagué (L'Hospitalet de Llobregat, Barcelona, Spain) and colleagues in the journal Lancet Oncology.
For this reason, say investigators, IUD use might be considered a "protective cofactor in cervical carcinogenesis."
Several large clinical and epidemiologic studies have reported inconsistent results when examining the association between cervical cancer and IUD use, but many of these trials did not account for HPV status.
In the current analysis, the researchers pooled data from two studies by an international research program on HPV and cervical cancer.
One of the trials included 10 case-control studies of cervical cancer, while the other included data from 16 HPV prevalence surveys of women in the general population. In total, 2205 women with cervical cancer and 2214 matched controls were included in the case-control studies, and 15,272 healthy women from the HPV surveys.
After adjusting for multiple confounding variables, including cervical HPV DNA and the number of previous Pap smears, there was a 45% lower risk for cervical cancer associated with use of IUDs.
Ever-use of IUDs was associated with a significant 44% lower risk for squamous cell carcinoma and a significant 54% lower risk for adenocarcinoma and adenosquamous carcinoma.
Short-term users and those who used IUDs for as long as9 years were equally protected from the risk for cervical cancer.
There was no association observed between IUD use and the detection of cervical HPV DNA in women without cervical cancer, the researchers note.
In an editorial accompanying the study, Karl Ulrich Petry (Klinikum Wolfsburg, Germany) said the results were surprising but should restore confidence in the safety of IUDs. Importantly, the data provides strong evidence to contradict the popular belief that IUD use increases the risk for cervical cancer.
Although the mechanism underlying the protective effect of IUDs is unknown, Castellsagué and colleagues suggest the devices might cause a chronic, low-grade inflammatory response in the endometrium, endocervical canal, and cervix that could modify the course of HPV infections.
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By MedWire Reporters