Age-related trends in the incidence of metastatic colorectal cancer over the last 10 years: A retrospective analysis in commercially-insured population in the United States

46 Background: Previous studies have suggested age-related shifts in the incidence of metastatic colorectal cancer (mCRC). However, more contemporary data is needed to further understand the continuous changes in the distribution of mCRC and patient characteristics across different age groups. Methods: A retrospective observational study was conducted using the Optum Clinformatics database to estimate the incidence rates (IRs) and temporal trends of newly diagnosed mCRC during 2010-2019, stratified by age categories (18-49; 50-64; and 65+). IRs were calculated as the actual patient number of newly diagnosed mCRC divided by the overall enrollment number. The IRs were standardized to the 2010 US population and trends over time were characterized using annual percentage changes (APCs). Results: Total of 23,970 newly diagnosed patients with mCRC were identified during 2010-2019. Median age was 71 years, 65% of patients were white, and 68% of patients had commercial Medicare insurance. Most patients (69%) were 65 years of age or older at the time of mCRC diagnosis. Patients characteristics were similar across age groups, except for race and geographic region. The proportion of Hispanic (12.6%) and Asian (4.7%) mCRC patients was higher in the younger 18-49 group than in the 50-64 (respectively 9.4% and 3%) and 65+ groups (respectively 9.5% and 2.9%). Higher proportions in the 18-49 (44.4%) and 50-64 (47.5%) groups than in the 65+ group (37.6%) were from the South, while higher proportions in the 65+ group were from the West and Northeast (24.4% and 14%). Standardized IRs of mCRC decreased by 22% from 64.4 in 2010 to 50.5 per 100,000 in 2019 among patients 65+, with an APC of -2,11. Standardized IRs increased over the same period by 15% in the 50-64 group, APC = 2.33 and by 22% in the 18-49 age group, APC = 2.8. Conclusions: Temporal changes in mCRC incidence in a large commercially insured population during 2010-2019, showed an increasing trend in younger patients and a decreasing trend in patients 65+. The highest increase in IRs from 2010 to 2019 occurred in the 18-49 age group. Hispanic and Asian patients were more present among the 18-49 than among the older patient groups, and there were geographic differences among the age groups. The changes in age- distribution and evolving patient characteristics need to be considered in the delivery of treatments and care for mCRC.