Colonic diseases: epidemiology, risk factors, diagnosis, and prevention (Global trends and data from Kazakhstan). A literature review

Relevance. Colorectal cancer, Crohn’s disease, ulcerative colitis, and colonic polyposis are major public health problems. These diseases reduce quality of life, increase disability and healthcare costs, and affect screening policy. Population aging, urbanization, and lifestyle changes have altered their incidence and age distribution in many countries. This burden makes their epidemiological assessment particularly important for public health planning, prevention, early detection, and organization of appropriate healthcare services. Objective. To summarize recent evidence on the epidemiology, risk factors, diagnosis, and prevention of major colon diseases worldwide and in Kazakhstan, with attention to regional differences and gaps in knowledge. Evidence was considered globally and nationally to provide comparative perspective. Methodology. A structured narrative literature review was conducted using PubMed, Scopus, eLibrary, and Google Scholar. The initial literature search was performed from June to August 2025, and the evidence base was subsequently updated to include relevant publications available through October 2026. The review primarily covered literature published between 2015 and 2026, with earlier landmark studies included where appropriate. Eligible sources comprised original research articles, systematic reviews, meta-analyses, clinical guidelines, authoritative reference materials, and official epidemiological and statistical reports. A total of 89 sources were included in the final narrative synthesis. Results. Colorectal cancer remains a major contributor to cancer incidence and mortality worldwide and in Kazakhstan. According to GLOBOCAN 2024 estimates, colorectal cancer accounted for 3,598 new cases (12.1% of all estimated cancer cases) in Kazakhstan. National statistical data demonstrated regional differences in colorectal cancer incidence and the continued occurrence of advanced-stage disease. Colorectal carcinogenesis involves chromosomal instability, microsatellite instability, and serrated neoplasia pathways, while hereditary syndromes contribute to increased individual risk. Advances in image-enhanced endoscopy, artificial intelligence-assisted colonoscopy, capsule endoscopy, and molecular testing offer additional diagnostic opportunities. However, gaps remain in population-based epidemiological data on inflammatory bowel diseases and colonic polyposis in Kazakhstan. Conclusions. The reviewed evidence highlights the importance of risk-factor modification, organized colorectal cancer screening, early detection and removal of precancerous lesions, and risk-adapted surveillance of individuals with hereditary predisposition. For Kazakhstan, priorities include improving screening quality, strengthening national cancer registration and epidemiological monitoring, expanding access to diagnostic services, and developing population-based research on inflammatory bowel diseases and colonic polyposis. Modern diagnostic technologies should complement established clinical pathways rather than replace colonoscopy and histological examination. Keywords: colorectal neoplasms, Crohn disease, ulcerative colitis, intestinal polyposis, epidemiology, Kazakhstan.