Trends and disparities in appendiceal cancer mortality in the United States from 1999 to 2023.

e15678 Background: Appendiceal cancer (AC), once rare, is now recognized as a complex disease with rising mortality. At diagnosis, 74% of AC cases are already metastatic. No standardized chemotherapy exists for advanced cases, despite an alarming 232% increase in incidence in the United States, predominantly in individuals under 50 years. We analyzed U.S. mortality patterns by demographics and geography to identify high-risk groups. Methods: A retrospective analysis was performed using the CDC WONDER database. Deidentified death certificate data were extracted through ICD-10 code C18.1 to identify Appendiceal cancer–related deaths from 1999 to 2023. We analyzed mortality disparities by gender, race/ethnicity, states, and urban/rural classification. Age-adjusted mortality rates (AAMR) per 100,000 with 95% CI were reported. Trends and annual percent change (APC) were assessed using Joinpoint regression. Results: Between 1999 and 2023, 15,928 appendiceal cancer–related deaths were recorded in the United States. AAMRs increased significantly from 0.08 per 100,000 in 1999 to 0.24 in 2017 (APC: 5.61; 95% CI: 5.14–6.07), followed by stabilization through 2023 (APC: 1.03; 95% CI: −0.27–2.35). Females accounted for 8,741 deaths versus 7,187 among males and consistently had higher AAMRs. Female AAMRs rose from 0.10 to 0.25 (APC: 5.86; 95% CI: 5.23–6.51), while male AAMRs increased from 0.08 to 0.26 (APC: 6.55; 95% CI: 5.41–7.70), with both stabilizing after 2017. NH-White individuals had the highest AAMR (3.95), followed by NH-Black individuals (3.73), with Hispanics/Latinos lowest (1.43). NH-Whites showed the steepest rise (APC: 6.31; 95% CI: 5.62–7.00), while NH-Black individuals increased steadily (APC: 5.94; 95% CI: 4.36–7.53). State-level AAMRs ranged from 0.08 in Nevada to 0.30 in Delaware, with top-decile states having 3-fold higher rates than bottom-decile states. Rural areas had the highest AAMR in 2020 (0.27) and showed a marked post-2004 increase (APC: 7.72; 95% CI: 6.34–9.12), exceeding metropolitan trends. Conclusions: Appendiceal cancer deaths are increasing in the United States, highlighting the need for targeted efforts to address this trend and reduce the risk of a growing health burden.