S592 A Silent Shift: Rising Mortality From Right-Sided Colon Cancer (1999–2020)

Introduction: Colorectal cancer is a major global health concern, ranking as the third most common cancer and the second leading cause of cancer-related deaths worldwide. Its incidence and mortality are highest in Westernized countries but are rising in developing nations due to changing lifestyles and dietary habits. Despite advances in treatment, late-stage presentation remains common, contributing to poor 5-year survival rates. Methods: We utilized the CDC WONDER Multiple Cause of Death database (ICD-10 code C18) to identify all colon cancer-related deaths in the U.S. from 1999 to 2020. Age-adjusted mortality rates per 1,000,000 persons (PMP), standardized to the 2000 U.S. census, were stratified by race, with right-sided colon cancer (cecum, ascending colon, hepatic flexure) analyzed separately for 2001–2020. Results: Between 1999 and 2020, colon cancer-related mortality in the U.S. showed a marked overall decline. Deaths decreased from 106,136 in 1999 to 48,096 in 2020, with the age-adjusted mortality rate dropping from 207.9 to 114.6 per million population (PMP). Racial disparities were evident throughout. In 1999, Black individuals had the highest mortality (288.1 PMP), followed by Whites (207.8), American Indian/Alaska Natives (129), and Asian/Pacific Islanders (114). By 2020, rates declined across all groups: Black individuals saw a 47% reduction (152.7 PMP), Whites 45% (114.6), American Indian/Alaska Natives 31% (89), and Asian/Pacific Islanders 31% (78.2).Trends in right-sided colon cancer (involving the cecum, ascending colon, and hepatic flexure) revealed a distinct 2-phase pattern. From 2001 to 2010, mortality rates declined significantly across all racial groups. Asian/Pacific Islanders saw a 65% drop (5.4 to 1.9 PMP), Black individuals 55% (4.9 to 2.2), and Whites 46% (3.7 to 2.0). However, from 2011 to 2020, this trend reversed for several groups. Mortality increased by 50% among Black individuals (2.6 to 3.9 PMP) and by 84% among Whites (1.9 to 3.5 PMP). In contrast, Asian/Pacific Islanders experienced a modest decrease (2.1 to 1.8 PMP). Conclusion: These findings highlight a concerning resurgence of right-sided colon cancer mortality among Black and White populations, suggesting evolving disparities in tumor biology, access to care, or effectiveness of screening modalities. Further targeted studies are needed to address these shifts and reduce emerging inequities.