Background: More than 99 percent of cervical cancers are associated with human papillomavirus (HPV), and approximately 70 percent of the tumors are attributed to infection from viral types 16 or 18. Recently introduced immunizations provide significant protection against these HPV types, and one vaccine also protects against types 6 and 11, which are responsible for approximately 90 percent of genital warts.

Vulvar, vaginal, and anal cancers also have been associated with HPV infection, but the relationship is less clearly defined. These cancer types are less common than cervical cancer, but because an estimated 70 percent of women are infected with HPV during their lifetime, any protection from virus-induced cancers could have a significant impact on population health. Hampl and colleagues studied the potential impact of HPV immunization on vulvar intraepithelial neoplasia (VIN), vaginal intraepithelial neoplasia (VAIN), anal intraepithelial neoplasia (AIN), and vulvar cancer.

The Study: The authors studied 258 biopsy samples from 241 women referred to two German specialized centers between 2000 and 2006 for treatment of lower genital tract dysplastic lesions. Data collected on each patient included age at diagnosis, smoking history, and history of HPV and human immunodeficiency virus infection. The number, location, and histopathologic characteristics of each lesion also were recorded. All specimen collection, interpretation, and data management followed identical protocols. All specimens were tested for HPV by DNA extraction, and HPV type was determined by polymerase chain reaction and sequencing.

Results: Because new classification systems do not use a category for low-grade lesions (the former VIN 1), 14 samples from 13 women were excluded from the analysis. Samples corresponding to VIN 2 or 3 were obtained from 168 women (183 samples). Eleven women (11 samples) had VAIN 2 or 3 lesions, 14 women (16 samples) had AIN 2 or 3 lesions, and 48 women had vulvar carcinoma. HPV DNA was identified in 92 percent of VIN samples, 91 percent of VAIN samples, 88 percent of AIN samples, and 60 percent of vulvar carcinomas. HPV types 16 or 18 were detected in 76 percent of VIN samples, 64 percent of VAIN samples, 81 percent of AIN samples, and 42 percent of vulvar carcinoma samples. Women with HPV-related disease were younger than women with HPV-negative lesions. The authors calculate that immunization for HPV types 16 and 18 would prevent about three fourths of VIN 2 or 3 cases, more than one half of vulvar carcinomas, and most anal cancers.

Conclusion: In the United States, approximately 3,700 new cases of vulvar cancer are diagnosed every year, with about 800 women dying from it. The incidence is increasing, particularly in younger women with HPV infection. The authors conclude that prophylactic immunization could prevent many of these lesions and help patients avoid complex and distressing treatment, as well as death, from several genital neoplasias.