Assessing Impact of HPV Vaccination on Cervical Cancer Incidence among Women Aged 15-29 Years in the United States, 1999-2017: An Ecologic Study

Background: To date, the impact of the human papillomavirus (HPV) vaccine on invasive cervical cancers in the United States has not been documented due, in part, to the time needed for cancer to develop and to recent changes to cervical cancer screening guidelines and recommendations, which complicate data interpretation. Methods: We examined incidence rates of cervical squamous cell carcinoma (SCC) and adenocarcinoma (AC) among women aged 15-29 years diagnosed during 1999-2017 using population-based cancer registry data covering 97.8% of the U.S. population. Trends were stratified by age and histology. The annual percent change in cervical cancer incidence per year was calculated using joinpoint regression. Results: During 1999-2017, SCC rates decreased 12.7% per year among women aged 15-20 years, 5.5% among women aged 21-24 years, and 23% among women aged 25-29 years. The declines in SCC rates were largest among women aged 15-20 years during 2010-2017, with a decrease of 22.5% per year. Overall, AC rates decreased 4.1% per year among women aged 15-20 years, 3.6% per year among women aged 21-24 years, and 1.6% per year among women aged 25-29 years. AC rates declined the most among women aged 15-20 years during 2006-2017, decreasing 9.4% per year. Conclusions: Since HPV vaccine introduction, both SCC and AC incidence rates declined among women aged 15-20 years, a group not typically screened for cervical cancer, which may suggest HPV vaccine impact. Impact: Timely vaccination and improved screening and followup among recommended age groups could result in further reductions in invasive cervical cancer.