Cervical Cancer Prevention (PDQ®): Prevention - Health Professional Information [NCI] - Evidence of Benefit
Epidemiologic studies to evaluate risk factors for the development of squamous intraepithelial lesions (SIL) and cervical malignancy demonstrate conclusively a sexual mode of transmission of a carcinogen. It is now widely accepted that human papillomavirus (HPV) is the primary etiologic infectious agent.[2,3,4] Other sexually transmitted factors, including herpes simplex virus 2 and Chlamydia trachomatis, may play a cocausative role. The finding of HPV viral DNA integrated in most cellular genomes of invasive cervical carcinomas supports epidemiologic data linking this agent to cervical cancer. More than 80 distinct types of HPV have been identified, approximately 30 of which infect the human genital tract. HPV types 16 and 18 are most often associated with invasive disease. Characterization of carcinogenic risk associated with HPV types is an important step in the process of developing a combination HPV vaccine for the prevention of cervical neoplasia. In a population-based study of HPV infection and cervical neoplasia in Costa Rica, 80% of high-grade squamous intraepithelial lesions (HSIL) and invasive lesions were associated with HPV infection by one or more of 13 cancer-associated types. In this study, the risk of about half of HSIL and invasive cervical cancer was attributable to HPV-16. HPV-18 was associated with 15% of invasive disease but only 5% of HSIL, suggesting that HPV-18 may have a role in more aggressive cases of cervical malignancy.
Barrier methods of contraception are associated with a reduced incidence of SIL presumptively secondary to protection from sexually transmitted disease.[7,8] The effectiveness of condom use for the prevention of HPV infections has been evaluated in a prospective study of women aged 18 to 22 years who were virgins. The number of vulvovaginal HPV infections was reduced with consistent condom use, and HPV infection rate was 37.8 infections per 100 patient-years among women whose partners used condoms 100% of the time in the 8 months before testing, compared with 89.3 infections per 100 patient-years among women whose partners used condoms less than 5% of the time (P trend = .005). No cervical SIL were detected among women reporting 100% condom use by their partner.