HPV vaccinations will slow oropharynx cancer rates but may take 25 years to see impact
According to projections in JAMA Oncology, it will take over 25 years to slow increasing oropharynx cancer incidence by human papillomavirus vaccinations because the disease will be observed in older population not yet vaccinated.
“HPV vaccination will eventually prevent oropharynx cancers (OPC), but it will take more than 25 additional years to see these impacts in the United States,” lead author, Yuehan Zhang, MS, a PhD candidate in cancer epidemiology at Johns Hopkins Bloomberg School of Public Health, told Healio Gastroenterology. “Overall incidence of oropharynx cancer is projected to continue to increase between 2020 and 2045 because most of these cancers will occur among older individuals who have not yet been vaccinated.”
Zhang and colleagues obtained data from the Surveillance, Epidemiology, and End Results program from 69,562 patients aged 34 years to 83 years diagnosed with oropharynx cancer. Investigators used the National Immunization Survey–Teen (n = 60,124) and National Health Interview Survey (n=16,904 participants) to obtain HPV vaccination data. Using a counterfactual scenario of no HPV vaccination and current levels of HPV vaccination, stratifying by sex, Zhang and colleagues applied age-period-cohort forecasting models to project expected 2018 to 2045 OPC incidence. The projected OPC incidence and number of OPC cases expected to be prevented by HPV vaccination served as the primary outcome.
According to Zhang and colleagues, OPC incidence between 2018 and 2045 is projected to decrease in younger individuals (36-45 years of age: 1.4 to 0.8 per 100 000 population; 46-55 years of age: 8.7 to 7.2 per 100,000 population) under current HPV vaccination rates. However, the incidence will continue to increase among older patients (70-83 years of age: 16.8 to 29 per 100,000 population). They also reported the correlation between HPV vaccination and overall OPC incidence through 2045 will remain modest (no vaccination vs. vaccination: 14.3 vs. 13.8 per 100 000 population in 2045).
While HPV vaccination is projected to decrease OPC incidence in patients aged 36 to 45 years (men: 48.1%; women: 42.5%) and aged 46 to 55 years (men: 9.0%; women: 22.6%) by 2045, rates will not meaningfully decrease among those aged 56 years or older because they are not vaccinated. However, Zhang and colleagues concluded that 6,334 OPC cases will be prevented by HPV vaccination between 2018 and 2045. Of these cases, 88.8% occur in the younger age groups.