Correlation between microsatellite instability (MSI) and 5-year survival in patients with colorectal cancer

The prognosis and treatment of colorectal cancer are based on its stage. The European Society for Medical Oncology published a guideline in 2012, which suggests that microsatellite instability (MSI) should be evaluated to determine the course of colorectal cancer. This study aimed to investigate MSI-high (MSI-H) as a prognostic factor for 5-year survival rates. 90 patients diagnosed with colorectal cancer who underwent resection surgery between 2008 and 2013 in Dr. Cipto Mangunkusumo Hospital, Jakarta, were included. The MSI status as a prognostic factor to determine the 5-year survival rate was analyzed after adjusting for the size and type of tumor, metastasis, and patient age. Of the 90 patients, 47 were followed up. The 5-year survival rates of patients with MSI-H were 33.3%, 22.2%, and 20% for stage II, III, and IV tumors, respectively, compared with 0%, 5%, and 0% for patients with MSI-low (MSI-L) (p = 0.003). Multivariate analysis showed that the hazard ratio for MSI-L was 2.421 (95% CI, 1.991-2.851) compared to MSI-H (p = 0.004). MSI-H is an important prognostic factor to determine the 5-year survival rate in colorectal cancer patients. It is found that patients with MSI-H have a more favorable prognosis compared with those with MSI-L.