S304 The Missed Screening Crisis: Rising Anal Cancer Related Mortality During HPV Vaccine Era Among Adults Aged ≥45 in the United States

Introduction: Human papillomavirus (HPV) is the most common sexually transmitted infection with nearly 80 million Americans living with some kind of HPV. High-risk types 16 and 18 have been associated with anal squamous cell carcinoma, which has exhibited increasing incidence and mortality rates in the United States (U.S.) over the recent decades. While the introduction of the HPV vaccine aimed to reduce HPV-associated cancers, its impact on older adults, particularly those aged ≥45, remains unclear. We conducted this study to assess trends in anal cancer-related mortality among U.S. adults aged ≥45 during the HPV vaccine era. Methods: A retrospective analysis was conducted using data from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) database. Anal cancer deaths were identified using International Classification of Diseases, Tenth Revision code C21, and age-adjusted mortality rates (AAMRs) per 100,000 population were calculated for adult men aged ≥45, standardized to the 2000 U.S. Census population. Mortality trends were examined by year, sex, urbanization, state, and U.S. Census region. Descriptive statistics and linear trend analysis were used to assess changes over time. Results: Between 1999 and 2023, a total of 22,192 deaths occurred from anal cancer. The AAMR increased from 0.7 in 1999 to 1.8 in 2023 per 100,000 population. Females had consistently higher AAMRs throughout the study duration compared to males (overall AAMR women 2 vs men 1.5). AAMR also varied by region (overall AAMR: West: 1.2; South: 1.1; Midwest: 1; Northeast: 0.9), and small metropolitan areas had relatively higher overall AAMR (0.8) than medium metropolitan and micropolitan/noncore nonmetropolitan (0.77) and large central (0.76) and fringe metropolitan areas (0.7) between 1999 and 2020. States in the top 90th percentile exhibited nearly twice the AAMRs compared to states that fell into the bottom tenth percentile. Conclusion: The mortality rate associated with anal cancer in the U.S. has shown an alarming rise over the past 2 decades. Significant demographic and geographic discrepancies are highlighted by the persistently higher mortality rates seen in females, regional disparities, and elevated rates in small metropolitan regions, highlighting the need for enhanced screening, aggressive management, and consistent surveillance for anal cancer in HPV patients at risk.