The results of an international study comprised of data from 10 case-control studies of cervical cancer and 16 human papillomavirus (HPV) prevalence surveys show that women who used an intrauterine device (IUD) had a 50 percent lower risk of cervical cancer, as compared to women who never used one. IUDs are devices that a gynecologist places through the cervix into the uterus in order to prevent pregnancy. Older versions of this device were associated with an increased risk of pelvic inflammatory disease, but newer models have eliminated this adverse effect.
In their study published in The Lancet Oncology, researchers led by a doctor from the Cancer Epidemiological Research Program in Catalonia, Spain examined data from over 20,000 women and found that, in addition to a lower risk of endometrial (uterine) cancer, IUD users also had a significantly decreased cervical cancer risk. This reduced risk was evident within the first year of IUD insertion, and the effect remained even after ten years of use. Interestingly, although HPV is the leading cause of cervical cancer, the researchers noted that IUD users did not have a decreased rate of HPV infections; however, it seems possible that the device might affect the progression of HPV infection to cervical cancer.
The authors speculate that IUDs might protect against cervical cancer during the process of device insertion, which may destroy inapparent precancerous lesions. Alternatively, they say, the presence of the device in the uterus may lead to chronic inflammation and a longer lasting immune response, thus reducing HPV progression in this manner as well.
ACSH's Dr. Gilbert Ross doesn t outright object to either hypothesis, though he does point out that the insertion or removal of an IUD is only minimally invasive; therefore, I find it hard to believe that such a brief procedure can destroy enough precancerous lesions to allay the progression of cervical cancer.