Human papillomavirus and cervical cancer: burden of illness and basis for prevention.

Genital infection with human papillomaviruses (HPV) is one of the most common sexually transmitted conditions. The central causal role in cervical carcinogenesis of the so-called high oncogenic-risk (HR)-HPV genotypes, such as HPV-16, has been established as a likely but not sufficient cause of virtually all cases of cervical cancer worldwide. HR-HPV infection also causes a substantial proportion of other anogenital neoplasms and oral squamous cell carcinomas. Infection with low-oncogenic-risk HPV, such as HPV-6 and -11, causes a large proportion of low-grade squamous intraepithelial lesions of the cervix and benign lesions of the anogenital areas known as condylomata acuminata (genital warts). Subclinical and clinical HPV infections are responsible for high morbidity and impose a great burden on the healthcare system. Organized or opportunistic screening with Papanicolaou (Pap) cytology in high-income countries has substantially reduced cervical cancer morbidity and mortality during the last 50 years. However, Pap cytology screening has failed to reduce cervical cancer mortality in many middle-income countries, and most low-income countries cannot make the necessary public health investments to deploy organized screening. The availability of 2 prophylactic HPV vaccines represents the best hope for preventing most cases of cervical cancer and HPV-associated diseases.