Abstract
Colorectal cancer (CRC) remains a leading cause of cancer-related mortality, highlighting the need for effective chemopreventive measures. Statins, commonly prescribed for cardiovascular disease, have demonstrated potential anti-cancer effects; however, epidemiological evidence remains inconsistent. This systematic review evaluates the relationship between statin usage and CRC risk, focusing on clinical outcomes. Following PRISMA guidelines, we conducted a thorough search through PubMed, Web of Science, Scopus, and Embase for relevant studies. Sixteen studies met our inclusion criteria, encompassing clinical and epidemiological research. Using the Newcastle-Ottawa Scale and the Cochrane Risk of Bias Tool, we synthesized the data and assessed bias risk. Most studies (11/16) indicated a protective effect of statins, with risk reductions between 12% to 24% (e.g., 95% adjusted odds ratio (AOR) of 0.87; CI: 0.83 to 0.91). However, conflicting findings were noted, including an increased risk of proximal CRC with long-term statin use (HR: 2.17) and neutral effects on metastatic CRC. Overall, statins show moderate chemopreventive effects against CRC, particularly in specific molecular subtypes. Discrepancies in outcomes may be attributed to differences in statin type, duration, and tumor biology. Future research should focus on biomarker-stratified randomized trials to refine statin-based prevention strategies.