S674 Diverging Trends in Colorectal Cancer Incidence by Age and Stage: A SEER Analysis, 2004-2022

Introduction: The incidence of colorectal cancer (CRC) among younger adults is rising in the United States. This increase raises concerns about screening practices which facilitates the early detection of CRC. In this study, we examined national trends in CRC incidence by age group and stage at diagnosis to understand the magnitude and implications of these changes. Methods: SEER data between 2004–2022 was analyzed for CRC incidence rates per 100,000, stratified by age (<50, 50–64, ≥65) and stage (localized, regional, distant) with Excel. Percent changes from 2004 to 2022 were calculated for each subgroup. Results: CRC incidence among adults <50 increased across all stages: localized disease increased 80%, regional 58%, and distant 53%. In the 50–64 group, the incidence of the localized disease declined by 16% and regional declined by 8%. However, the incidence of distant disease showed a slight increase of 3%. Adults ≥65 experienced marked declines at all stages: localized disease declined 53%, regional 43%, and distant 28%. The most pronounced relative increase in distant CRC was observed in <50, while older adults had mostly sustained declines. The change in CRC incidence between 2018-2022, after the screening age was decreased to 45, increased by 33% in localized, 22.5% in regional and 9.5% in distant disease among adults <50. The increase in incidence was lower during the previous 4-year period between 2014-2018, it increased by 11.1% in localized, 14.2% in regional and 10.5% in distant disease. Conclusion: CRC incidence is rising among adults <50 regardless of the stage. A substantial increase in metastatic disease was observed among adults <50. Adults >65 have seen significant declines, which reflects the impact of established screening programs. Between the years 2018-2022, the significant rise in the localized CRC incidence in adults <50 may suggest the change in CRC screening age was successful to detect CRC earlier. The rise in regional and distant CRC incidence between 2018-2022 may suggest that there are still gaps in early detection and screening for those <50. The continued incidence of distant-stage disease in the 50–64 group further suggests opportunities to improve screening uptake and early diagnosis in this population. These findings highlight gaps in early detection and underscore the need to enhance risk assessment and increase symptom awareness in younger populations. Targeted interventions are critical to address the growing burden of early-onset and advanced-stage CRC.