Geographical Disparities and Trends in Prevalence of Metastatic Colorectal Cancer in the United States

Background: Metastatic colorectal cancer (mCRC) remains a major public health challenge in the United States, with notable disparities in regional prevalence and outcomes. The Southern U.S. has consistently demonstrated higher rates of advanced-stage diagnoses, potentially reflecting healthcare access and socioeconomic inequities. Methods: A retrospective cohort study was conducted using the National Inpatient Sample (NIS) from 2016-2019. Adults with mCRC were identified using ICD-10 codes (C18.8, C18.9, C18.2, C18.4, C18.6, C18.7). Patients were stratified into four U.S. Census regions. Chi-square tests assessed regional differences in mCRC prevalence, and temporal trends were analyzed using the delta method. Statistical significance was set at p < 0.05. Results: Among 56,570 mCRC patients, the Southern region had the highest disease burden (39.71%), increasing from 39.56% in 2016 to 40.64% in 2019. The Western region showed a 9.5% rise, while the Northeast and Midwest declined by 8.3% and 4.96%, respectively. These findings align with national cancer data showing slower declines in colorectal cancer incidence in the South. Conclusions: Significant geographical disparities persist in metastatic colon cancer prevalence, with the South exhibiting the highest and rising burden. Socioeconomic disadvantages, healthcare access barriers, and limited Medicaid expansion are likely to contribute to these trends. Regional and policy interventions targeting prevention and early detection are urgently needed.