Microsatellite Instability and Survival in Stage II Colorectal Cancer: A Systematic Review and Meta-analysis

Background/Aim: About 15-20% of colorectal cancers (CRCs) have deficiency in a mismatch repair (MMR) protein. MMR has a high level of microsatellite instability (MSI-H). We have conducted this review and meta-analysis to determine the prognostic role of MSI-H status in stage II CRC. Materials and Methods: We searched PubMed, EMBASE, The Cochrane Library, Web of Science, and SCOPUS for studies reporting data on overall survival (OS) and disease-free or relapse-free survival (DFS or RFS) for MSI-H compared to microsatellite stable (MSS) CRC. Results: A total of 39 studies were analysed, including 12,110 patients. MSI-H status was associated with a significantly reduced risk of death (HR=0.64, 95%CI=0.52-0.8, p<0.01) and relapse (HR=0.59, 95%CI=0.45-0.77, p<0.01) in stage II CRC. Conclusion: MSI-H represents an important prognostic determinant in stage II CRC and may be considered when estimating the risk of recurrence in stage II CRC.