Cervical cancer prevention in the human papilloma virus vaccine era

Globally, cervical cancer is second only to breast cancer as the leading cause of cancer in women, with a global prevalence of 2.3 million. It is the third most common cause of female cancer-related mortality worldwide, and 82% of new cervical cancer cases occur in developing countries. As stated by WHO, "without screening programs, cervical cancer is detected too late and leads to death in almost all cases." However, even in Europe, the United States, and Canada, where most women have access to routine screening, approximately 30,000 women die each year. Infection with oncogenic types of HPV 16 and 18 is the most significant risk/causative factor in cervical cancer etiology, and worldwide HPV positivity in cervical carcinoma has been documented to be 99.7%. In 2006 Merck's quadrivalent vaccine was approved by FDA. It targets four HPV types (6, 11, 16, and 18) that are involved in cervical cancer, high and low grade squamous intraepithelial lesions, and anogenital warts. Results from combined Phase II/III studies show that the efficacy of vaccine was 95-100% against LGSIL and HGSIL related to HPV 16 and 18 and vaccine use led to a 99% reduction in the incidence of genital warts (related to HPV 6 and 11). Due to morbidity associated with infection with HPV types 6, 11, 16, and 18, a prophylactic quadrivalent HPV vaccine targeting these four HPV types is expected to substantially reduce the burden of HPV-related disease.