e18819 Background: Colorectal cancer is rising in prevalence and associated with high healthcare costs. We estimated trends in the US healthcare spending in patients with colorectal cancer between 1996 and 2016. Methods: We used data on national healthcare spending developed by the Institute for Health Metrics and Evaluations for the Disease Expenditure Project. Corresponding US age-specific prevalence of colon cancer was estimated from the Global Burden of Diseases Study. Prevalence-adjusted, temporal trends in the US healthcare spending in patients with colorectal cancer, stratified by age groups ( < 20, 20-44, 45-64, >65) and by type of care (ambulatory, inpatient, emergency department, pharmaceutical prescriptions, nursing care and government administration) were estimated using joinpoint regression, expressed as annual percent change (APC) with 95% confidence intervals. Results: Overall, annual US healthcare spending on colorectal cancer increased from $8.85 billion (95% CI $8.17 billion, $9.53 billion) in 1996 to $10.5 billion (95% CI $9.35 billion, $11.7 billion) in 2016, with total costs increasing by 0.9%/year (95% CI 0.1%, 1.6%). After adjusting for colorectal cancer prevalence, the absolute per capita spending decreased from $8848 to $8427 and there has been no significant change over time (APC 0.3%, 95% CI, -0.2%, 0.8%). However, spending in patients > 65 decreased significantly by 1.3%/year (95% CI -2.2%, -0.5%). Inpatient care was the largest contributor to total colorectal cancer-related expenditures: in 2016, 65.9% (95% CI 59.5%, 71.0%) and 19.7% (95% CI 14.8%, 25.8%) of the total cost were spent on inpatient care and ambulatory care, respectively. Between 1996-2016, increases in the price and intensity of care (defined by the cost per encounter) was the largest positive driver of changing healthcare spending, accounting for $5.02 billion ($2.60, $7.33 billion). Conclusions: After adjusting for rising prevalence, US healthcare spending on colorectal cancer has not changed significantly since 1996, while the per capita cost continues to decrease, primarily in patients > 65 years old. Inpatient care accounts for the majority of colorectal cancer-related expenditures.