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

Abstract

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 2.3% 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 follow-up among recommended age groups could result in further reductions in invasive cervical cancer.

Figure 1.. Timeline of relevant recommendations and guidelines in the United States for cervical cancer testing, HPV vaccination, screening, and management.

Abbreviations: HPV = human papillomavirus, FDA = Food and Drug Administration, ACS = American Cancer Society, ACOG = American College of Obstetrics and Gynecology, USPSTF = United States Preventive Services Task Force. This timeline depicts relevant events in the type of testing (Pap/HPV), HPV vaccination, age and frequency of testing, and management of cervical cancers and precancers.

Figure 2.. Cervical Cancer Observed and Predicted Incidence Trends among Women Aged 15–20 Years by Histology, United States, 1999–2017.

Data Sources: Center for Disease Control and Prevention’s National Program of Cancer Registries and the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. Incidence data compiled from cancer registries that met data quality standards from 1999 to 2017, covering 97.8% of the US population. AC refers to adenocarcinomas defined by ICD-O-3 histology codes 8140–8575; SCC refers to squamous cell carcinomas defined by ICD-O-3 histology codes 8050–8084 and 8120–8131. Black triangles represent observed incidence rates of SCC; black solid lines are the SCC modelled trends; black dotted lines are the SCC predicted trends; gray squares represent observed incidence rates of AC; gray dotted lines are the AC modelled trends; gray dotted lines are the AC predicted trends. Predicted rates were estimated based on the trends in 1999 to 2008 continuing to 2017 (see methods section for further information on methodology).

Figure 3.. Cervical Cancer Observed and Predicted Incidence Trends among Women Aged 21–24 Years by Histology, United States, 1999–2017.

Data Sources: Center for Disease Control and Prevention’s National Program of Cancer Registries and the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. Incidence data compiled from cancer registries that met data quality standards from 1999 to 2017, covering 97.8% of the US population. AC refers to adenocarcinomas defined by ICD-O-3 histology codes 8140–8575; SCC refers to squamous cell carcinomas defined by ICD-O-3 histology codes 8050–8084 and 8120–8131. Black triangles represent observed incidence rates of SCC, black solid lines are the SCC modelled trends, black dotted lines are the SCC predicted trends; gray squares represent observed incidence rates of AC, gray dotted lines are the AC modelled trends, gray dotted lines are the AC predicted trends. Predicted rates were estimated based on the trends in 1999 to 2008 continuing to 2017 (see methods section for further information on methodology).

Figure 4.. Cervical Cancer Observed and Predicted Incidence Trends among Women Aged 21–24 Years by Histology, United States, 1999–2017.

Data Sources: Center for Disease Control and Prevention’s National Program of Cancer Registries and the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. Incidence data compiled from cancer registries that met data quality standards from 1999 to 2017, 97.8% of the US population. AC refers to adenocarcinomas defined by ICD-O-3 histology codes 8140–8575; SCC refers to squamous cell carcinomas defined by ICD-O-3 histology codes 8050–8084 and 8120–8131. Black triangles represent observed incidence rates of SCC, black solid lines are the SCC modelled trends, black dotted lines are the SCC predicted trends; gray squares represent observed incidence rates of AC, gray dotted lines are the AC modelled trends, gray dotted lines are the AC predicted trends. Predicted rates were estimated based on the trends in 1999 to 2008 continuing to 2017 (see methods section for further information on methodology).