Background: Many studies have disclosed the prognostic effect of microsatellite instability (MSI) and/or loss of mismatch repair proteins in colorectal cancer. Nevertheless, little evidence supports their role in the decision-making of adjuvant therapy for patients with stage II disease.
Materials and methods: The aim of this systematic review was to evaluate the prognostic and/or predictive role of MSI status in patients with stage II colorectal cancer on disease-free survival and overall survival. MEDLINE, EMBASE, and Cochrane libraries were searched to identify eligible studies.
Results: Only 2 of 389 articles identified fulfilled the eligibility criteria. In both treated and untreated patients, high-level MSI improved disease-free survival compared with low-level MSI, suggesting a prognostic role but not supporting the hypothesis of a predictive effect of MSI.
Conclusions: Further studies are needed to explore the predictive role of MSI/mismatch repair proteins, because available data do not allow definitive conclusions.
Keywords: Adjuvant therapy; Colorectal cancer; Mismatch repair proteins; Predictive factor; Prognostic factor.
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