Examining age-specific trends in the incidence of human papillomavirus-associated oropharyngeal cancer in the United States.

6081 Background: The incidence of human papillomavirus (HPV) infection-associated oropharyngeal cancer (OPC) has been steadily rising in the United States, with HPV surpassing behavioral risk factors like tobacco and alcohol use as the leading cause of OPC, particularly in men. We examined the impact of the HPV vaccine on the incidence of OPC, accounting for age, gender, and lifestyle behavior. Methods: Cancer incidence was extracted from the United States Cancer Statistics Public Use Database (USCS). Data on alcohol and tobacco consumption were obtained from the Substance Abuse and Mental Health Services Administration (SAMHSA). The Behavioral Risk Factor Surveillance System (BRFSS) was employed to collect HPV vaccination and screening information. Information on HPV infection and number of sexual partners was provided by the National Health and Nutrition Examination Survey (NHANES). The Joinpoint Regression Program (National Cancer Institute) and Pearson correlation coefficients were used for statistical analyses. Results: Between 2001 and 2021, oropharyngeal cancer (OPC) incidence rates increased in males by 2.3% (p<0.001) compared to a 0.74% annual increase in females (p=0.002). Compared to the rising incidence of OPC in older men, the younger cohort showed a significant decrease in the incidence of OPC. Specifically, younger males 35-39 years old and 40-44 years old had a 1.86% decrease (p=0.004) and 1.37% decrease (p=0.005) in OPC incidence per year, compared to a rising incidence of 1.66% (p<0.001) and 2.56% (p<0.001) annually among males 60-64 years old and 65-69 years old, respectively. With the 2009 approval of the HPV vaccine for young men, we investigated whether this was associated with decreased OPC incidence. Indeed, HPV vaccination showed a significant negative correlation with OPC incidence in men younger than 45 (r=-0.818; p=0.001). We then evaluated whether substance use and sexual practices, both risk factors for OPC, have changed during this time. Among 18-25 year olds surveyed in SAMHSA from 2003 to 2021, we found that overall consumption of alcohol decreased by 11.0% (p<0.05) and tobacco use decreased by 22.8% (p<0.05), even though alcohol and tobacco use were initiated at higher rates in this younger age cohort. Using the NHANES database from 2009-2016, we found that the rate of oral HPV infection, assessed via oral cavity rinses, has not significantly changed (7.6% to 7.2%; p=0.896). Similarly, there was no change in the proportion of people with more than four lifetime oral sex partners (36.0% to 39.0%; p=0.684). Conclusions: This study reveals a strong inverse relationship between HPV vaccination rates and OPC incidence in men under 45 years, suggesting that vaccination efforts may be effectively reducing cancer risk in this group. The decreasing rate of alcohol and tobacco consumption in this age group may also contribute to our findings.