Microsatellite instability leads to poor prognosis in patients with early-stage endometrial cancer? a meta-analysis

Abstract Background Poor prognosis of early-stage endometrial cancer (EC) is often accompanied by microsatellite instability (MSI). We hypothesized that MSI is an independent marker for poor prognosis of early-stage EC. To demonstrate this hypothesis, we evaluated the correlation between MSI and early-stage EC prognosis by meta-analysis. Methods Databases such as PubMed, EMBASE and the Cochrane Cooperative Library were searched from inception to October 2020, respectively. The disease-free survival (DFS), the overall survival (OS), and the progression-free survival (PFS) were pooled to analyze the correlation between MSI and prognosis in patients with early-stage EC. Besides, Egger's regression and Begg's test were used to detect Publication bias. Results There were 7 studies met the inclusion criteria and were enrolled in our meta-analysis with a sample size of 1150, and the included patients with early-stage EC were all endometrioid endometrial cancer (EEC). The pooled hazard ratios (HRs) in early-stage EC shows that MSI is significantly associated with lower DFS [HR = 3.90, 95%CI (2.81–6.99), p = 0.000], OS [HR = 1.48, 95%CI (1.12–1.96), p = 0.006], and PFS [HR = 2.41, 95%CI (1.05–5.52), p = 0.038]. There was no significant heterogeneity in the studies pooled analysis of DFS, OS, and PFS. There was also no statistical publication bias, the P-value of Egger`s test of OS and DFS is p = 0.535 and p = 0.639 respectively. Conclusion MSI is most likely an independent marker of poor prognosis in early-stage EC, and this correlation is even more significant in patients with EEC.