Colorectal Cancer in Young Adults - A Comprehensive Systematic Review and Meta-Analysis on Global Trends and Perspectives

Colorectal Cancer in Young Adults

Abstract

Background: The incidence of early-onset colorectal cancer (EOCRC), defined as CRC diagnosed in individuals under age 50, is rising globally. This systematic review and meta-analysis synthesizes global epidemiological trends, risk factors, clinical characteristics, and outcomes of EOCRC.

Methods: Following PRISMA 2020 guidelines, we systematically searched PubMed, Scopus, and Web of Science from January 2000 to August 2025. Studies reporting incidence, prevalence, risk factors, or outcomes in EOCRC populations were included. Quality assessment employed the Cochrane Risk of Bias Tool for randomized studies and ROBINS-I for observational studies. Meta-analyses were performed using random-effects models where sufficient homogeneity existed.

Results: From 3,847 screened records, 115 studies met inclusion criteria. EOCRC incidence is rising in 27 of 50 countries, with average annual percentage changes ranging from 1.3% to 4.0%. Pooled analysis showed EOCRC accounts for 10-12% of all CRC diagnoses globally. Risk factors include obesity (RR 1.54, 95% CI 1.31-1.81), hereditary syndromes (25% of cases), and Western dietary patterns. EOCRC presents with distinct clinicopathologic features including higher rates of left-sided tumors and signet ring histology.

Conclusions: EOCRC represents a growing global health burden with unique epidemiological and clinical characteristics requiring tailored prevention, screening, and management strategies.

Bangladesh J Medicine 2026; 37(3): 183-191