Background: Population-based monitoring of HPV type-specific cervical cancer precursors may be an early indicator of HPV vaccine impact on cervical disease. In 2007, the CDC, in collaboration with the Emerging Infections Programs (EIP) Network piloted a multi-site population and laboratory-based system (HPV-IMPACT) to monitor cervical intraepithelial neoplasia (CIN) 2/3 and adenocarcinoma in situ (AIS).
Objectives: To describe the epidemiology of CIN2/3 and AIS diagnoses before HPV vaccine impact.
Methods: Active CIN2/3 and AIS case ascertainment is ongoing in 5 well-defined catchments with a combined population of about 1.4 million females ≥18. Cases are obtained by direct reporting from pathology laboratories serving catchment residents. Vaccine history and HPV types associated with lesions are determined on 18-39 year-old cases. Representativeness of data is monitored by regular contact and periodic laboratory audits of labs.
Results: In 2008, diagnosis rates per 1000 population in CT, NY and CA in 18-39 year-old females were 5.1 , 4.8, and 2.3, respectively. The distribution of CIN grades were: 57% CIN2, 28% CIN3, 14% CIN2/3 in CT, 58% CIN2, 23% CIN3, 16% CIN2/3 in NY, 42% CIN2, 30% CIN3, 25% CIN2/3 in CA. AIS represented <2% of cases in all sites. The majority of cases (~60%) occurred in 18-29 year olds in CT and NY compared with 43% in CA; 30-39 year olds represented ~20% of cases in CT and NY and 35% in CA.
Conclusions: Continuous CIN2/3 and AIS data collection is ongoing in 5 HPV-IMPACT sites. Differences by site may reflect incomplete reporting or CIN2/3 ascertainment. Data from the first years of this project will provide important information to evaluate future impact of HPV vaccine on cervical cancer precursors.
Implications for Programs, Policy, and/or Research:Implementation of a sustainable monitoring system for HPV-associated disease will enable evaluation of the direct impact of the vaccine.