Characterizing the clinical presentation of early-onset colorectal cancer: Constipation as a novel marker.

35 Background: While colorectal cancer (CRC) incidence overall is declining, early-onset CRC (EOCRC, diagnosed before age 50) continues to rise. In response, screening guidelines were lowered from age 50 to 45 in 2021. However, many EOCRC cases still occur before age 45, highlighting the need to identify high-risk individuals beyond current criteria. We hypothesized that EOCRC presents with distinct symptom profiles compared to late-onset CRC (LOCRC). Methods: We analyzed 2020–2022 National Inpatient Sample data, conducting 1:1 age-matched comparisons between CRC patients and controls without CRC. Symptoms were identified using ICD-10 codes. Adjusted odds ratios (aORs) were calculated and stratified by age and sex. Bonferroni correction was applied for 12 symptom groups (p < 0.004). Results: We identified 18,017 hospitalizations involving EOCRC. Constipation was strongly associated with EOCRC (aOR 2.50 vs. controls, p < 0.001), particularly among younger adults. In adults under 40, the aOR was 2.79 in men and 5.72 in women (both p < 0.001). In contrast, constipation was minimally associated with LOCRC (aOR 1.12, p = 0.020). Among constipation-related hospitalizations, CRC prevalence was 0.96% in adults aged 35 to 39 and 1.31% in those aged 40 to 44. These rates were comparable to or higher than the 1.07% prevalence in general hospitalizations of adults aged 45 to 49. Conclusions: Constipation was significantly associated with EOCRC hospitalizations, particularly in women under 40. Among hospitalized adults aged 35 to 44, constipation may signal a CRC likelihood comparable to that of patients nearing current screening age. These findings support further evaluation of constipation as a potential early warning sign in CRC risk stratification. Age-stratified odds ratios and 95% confidence intervals for constipation and colorectal cancer, by sex. Group