Early-Onset Colorectal Cancer in Patients under 50 Years of Age: Demographics, Disease Characteristics, and Survival

Incidence of early-onset colorectal cancer (EO-CRC) is increasing in younger demographics. This study analyzes disease-specific survival in individuals under 50 years of age.Patients with colorectal malignancy were identified in the Surveillance Epidemiology and End Results (SEER) database from 2004 to 2015. Cases were categorized into typically screened (age 50-79 years) and non-typically screened (age 20-49 years) cohorts, as well as by decade. Kaplan-Meier curves and Cox proportional hazard models were used to study survival.A total of 240,772 patients with colorectal cancer were analyzed. Average annual percent change in incidence was -0.24% among typically screened patients and +1.12% among patients with EO-CRC. Patients with EO-CRC more frequently presented with distal tumors (70.6% vs. 57.6%, P < .001) and advanced tumor stage (61.3% vs. 48.6%, P < .001). Patients aged 50 and over had comparable 5 year disease-specific survival to younger patients (68.2% vs. 66.4%, P = .31); however, patients in the 3rd, 4th, and 8th decade of life had particularly low survival rates (59.0% vs. 65.8% vs. 65.8%, logrank P < .001). Patients aged 20-29 years had the most increased risk of cause-specific mortality on univariable Cox regression analysis [HR 1.43, 95% CI 1.31-1.56; P < .001], although this was not significant on multivariable analysis [HR 1.06, 95% CI 0.97-1.15; P = .201]. Male sex, older age, advanced stage, rectal and/or cecal primary, and earlier year of diagnosis were independently associated with increased mortality.Patients with EO-CRC are diagnosed at a later stage and have lower disease-specific survival than those in typically screened cohorts. Additional studies on tumor biology and surveillance strategies are needed to improve outcomes in this population.