Clinical perspectives on the role of the human papillomavirus vaccine in the prevention of cancer.

The role of human papillomavirus (HPV) in the genesis of cervical cancer has been well documented, and an increasing body of literature exists with regard to the role of HPV in other cancers, including cancers of the head and neck. With the recent expansion of the United States Food and Drug Administration's approval of the quadrivalent HPV virus-like particle vaccine to include men and boys and approval of the bivalent vaccine this year, the controversies regarding who should be vaccinated, at what age is vaccination most appropriate, and the limitations of the available HPV vaccines are increasing. Health care providers are challenged with evaluating the current, but continually changing, clinical evidence when making critical decisions for their patients. A literature search of MEDLINE and SciVerse Scopus was conducted for articles published from 1998-April 2010 regarding HPV, HPV-related cancers, and HPV vaccines. Although both HPV vaccines were greater than 90% effective in the prevention of cervical cancer precursors in an according-to-protocol cohort, both vaccines were significantly less effective in the intent-to-treat population. In patients who achieved seroconversion, the geometric mean titers decrease dramatically within the first 2 years after vaccination, and then continue to decline at a slower rate. No effective antibody titer has been defined for either vaccine, and no studies have been conducted with documented HPV exposure after vaccination. With low efficacy rates in an intent-to-treat population and the potential for waning immunity, it is imperative for women to continue to receive regular Pap tests and gynecologic examinations. Although vaccine administration was shown to be cost-effective when administered to adolescent girls, many of these simulations overestimated the durability of protection, efficacy rates in sexually active women, impact of incomplete vaccination, or necessity of boosters in the future. Whereas the introduction of the HPV vaccine was an enormous advancement in the cancer prevention research arena, optimization of its clinical use is still needed.