In a population-based age-period-cohort study reported in JAMA Oncology, Zhang et al estimated that current human papillomavirus (HPV) vaccination rates will have a limited impact on overall oropharyngeal cancer incidence through 2045, due to a high risk of oropharyngeal cancer in unvaccinated older individuals.
As stated by the investigators, “Oropharyngeal cancer incidence has increased for several decades in the United States. It is unclear when and how this trend will be affected by current HPV vaccination trends.”
Oropharyngeal cancer incidence data were obtained from the Surveillance, Epidemiology, and End Results program for 69,562 patients aged 34 to 83 years. HPV vaccination data were obtained from the National Immunization Survey–Teen (n = 60,124) and National Health Interview Survey (n = 16,904).
Data were collected from January 1992 to December 2017. Age-period-cohort forecasting models projected 2018 to 2045 incidence of oropharyngeal cancer using the scenarios of no HPV vaccination and current levels of HPV vaccination.
It is estimated that by 2045, 72.2% of individuals aged 36 to 45 years, 36.6% of those aged 46 to 55 years, 8.7% of those aged 56 to 69 years, and 0% of those aged 70 to 83 years will have been vaccinated.
With current HPV vaccination rates, the overall oropharyngeal cancer incidence rate is projected to continue to increase between 2018 and 2045, from 11.9 to 13.8 per 100,000 population. Decreases from 1.4 to 0.8/100,000 are projected for individuals aged 36 to 45 years in 2045 (including reductions of 48% in men and 43% in women) and from 8.7 to 7.2/100,000 for those aged 46 to 55 years (including reductions of 9% in men and 23% in women). However, projected rates are not meaningfully reduced in those aged ≥ 56 years, with a projected increase from 16.8 to 29.0/100,000 among those aged 70 to 83 years.
Based on the scenario of expected cases with no vaccination, the association of HPV vaccination with overall oropharyngeal cancer incidence is estimated to be small, with projections of 14.3 cases/100,000 with no vaccination vs 13.8/100,000 with vaccination by 2045. The number of incident oropharyngeal cancer cases between 2018 and 2045 is estimated at 736,518 in the scenario with no vaccination, with vaccination projected to be associated with a reduction of 6,334 cases; of these cases, 88.8% are projected to be among individuals aged ≤ 55 years.
It is projected that beginning in approximately 2033, approximately 100 cases per year will be prevented by vaccination, increasing to 998 by 2045. Despite the projected decreased incidence in younger individuals, the overall annual number of new cases is projected to increase from 19,690 to 28,670 between 2018 and 2045.
The investigators concluded, “According to the projections of this population-based age-period-cohort study, current HPV vaccination rates will have a limited association with overall oropharyngeal cancer incidence through 2045 because older individuals who have not yet been vaccinated remain at high risk for oropharyngeal cancer. However, reductions in oropharyngeal cancer incidence should occur among young and middle-aged adults, the group at lowest risk of diagnosis. These findings forecast a continued shift in the landscape of oropharyngeal cancer to an older population.”
Gypsyamber D’Souza, PhD, of the Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was supported by a grant from the National Institute of Dental and Craniofacial Research. For full disclosures of the study authors, visit jamanetwork.com.