The early-onset paradox: Advanced-stage colon cancer at presentation across socioeconomic and health system factors.

Abstract

136 Background: Early-onset colon cancer (EOCC) incidence is rising sharply, yet younger patients consistently present with more advanced disease than older adults. This study investigates whether this stage discrepancy persists after adjusting for socioeconomic status (SES) and healthcare system factors, and examines treatment timeliness following diagnosis. Methods: We conducted a retrospective cohort study using the National Cancer Database (2004–2023), identifying 1,064,679 adults with stage I–IV colon adenocarcinoma. Cohorts were stratified by age: younger (<50 years) and older (≥50 years). To evaluate the potential impact of screening eligibility, the younger cohort was further stratified into those aged 45–49 (newly screening-eligible) and <45 (pre-screening age). The primary outcome was advanced-stage disease (stage III/IV) at diagnosis. Secondary outcomes included time to treatment initiation (TTI) and treatment delay (>30 days). Multivariable logistic regression adjusted for demographics, insurance, comorbidities, income/education quartiles, and healthcare access variables. Results: Of 1,064,679 patients, 10.5% (n=112,235) were <50 years. Within the younger cohort, approximately 42% were aged 45–49 and 58% were <45. Younger patients demonstrated higher SES markers, including a greater proportion in the highest income quartile (34.5% vs 31.7%) and metropolitan residence (87.3% vs 84.7%) (p<0.001). Despite these advantages, younger patients were significantly more likely to present with advanced-stage disease (59.5% vs 48.0%, p<0.001). This increased odds of advanced presentation persisted in the 45–49 subgroup despite their eligibility for routine screening. In multivariable analysis, age <50 remained an independent predictor of advanced stage (OR 1.47; 95% CI 1.44–1.50). Paradoxically, younger patients experienced shorter median TTI (6 vs 9 days) and fewer treatment delays >30 days (15.9% vs 22.6%, p<0.001), a trend that remained significant across all stages. Conclusions: A striking paradox exists in EOCC care; younger patients present with significantly more advanced disease despite favorable socioeconomic profiles and shorter intervals to treatment once diagnosed. This suggests the primary breakdown occurs before they ever reach an oncologist. While our data cannot track the exact moment symptoms began, these findings support an "upstream" failure where current detection strategies miss younger adults until the disease has progressed. Improving outcomes requires us to look beyond treatment speed and focus on earlier detection.