Closing the Diagnostic Gap in Early-Onset Colorectal Cancer: Red-Flag Symptoms, Screening, and Inherited Risk

Abstract

Simple Summary Early-onset colorectal cancer is diagnosed before the age of 50, and its incidence is rising in many populations. Because most younger adults are not routinely offered screening, diagnosis usually follows the onset of symptoms. Rectal bleeding, persistent abdominal pain, sustained changes in bowel habits, and unexplained iron-deficiency anemia warrant timely evaluation. A family history of colorectal cancer or advanced colorectal polyps, or an inherited cancer-predisposition syndrome, may identify people who require earlier or more intensive surveillance. Screening beginning at age 45 can detect clinically important precancerous lesions, although direct evidence that starting population screening before age 50 reduces colorectal cancer incidence or mortality remains limited. A pragmatic strategy should combine prompt investigation of warning signs, systematic collection of family history, appropriate genetic counseling and testing, and equitable access to high-quality diagnostic and screening services.