BACKGROUND/AIMS: While overall rates of colorectal cancer (CRC) have declined in individuals aged above 50 years of age, this decline has not been seen in younger individuals who do not benefit from current screening guidelines. We sought to describe the prevalence of CRC in adults 20-39 years of age without family history of CRC or inflammatory bowel disease as early-onset CRC (EoCRC), evaluate associated signs and symptoms and medical comorbidities in EoCRC, and compare them with individuals aged 20-39 years without CRC (NoCRC). Our secondary aim was to compare EoCRC with individuals aged 40 years and above with CRC (LoCRC).

METHODS: Utilizing a commercial database (Explorys Inc, Cleveland, OH), we identified a cohort of patients aged 20-39 years with first ever diagnosis of CRC between 2013 and 2018 based on the Systematized Nomenclature of Medicine-Clinical Terms. We calculated the overall prevalence rate of EoCRC, described age, race, and gender-based prevalence rates of EoCRC, and identified associated symptoms and medical comorbidities associated with EoCRC.

RESULTS: The overall rate of EoCRC was 18.9/100,000. Compared to NoCRC, EoCRC patients were more likely to be Caucasian and female, with predominant symptoms of hematochezia, anemia, and decreased appetite. EoCRC group had higher prevalence rates of medical comorbidities such as diabetes, smoking, and obesity. Compared to LoCRC, EoCRC group presented more frequently with left-sided CRC and rectal cancers.

CONCLUSION: This is one of the largest studies to date to describe the epidemiology of EoCRC in USA. We found EoCRC to occur predominantly in the Caucasian and female population. EoCRC presented more frequently with left-sided and rectal CRC. We also identified signs/symptoms as well as comorbidities associated with EoCRC. Patients with these features may benefit from earlier screening.