Mismatch Repair Protein Deficiency Does Not Affect Disease Free Survival in Type I Endometrial Carcinoma

Background: This study aimed to analyze the correlation between the 3-year disease-free survival (DFS) and mismatch repair (MMR) protein levels in patients with type 1 endometrial carcinoma. Many studies have reported different results regarding the role of MMR in the prognosis of endometrial carcinoma; therefore, we aimed to identify this association in our hospital. Methods: This observational study employed a historical cohort design and included patients with type 1 endometrial carcinoma who underwent surgery at Dr. Soetomo Hospital between January 2017 and December 2019. Medical records and paraffin blocks meeting these criteria were obtained. MMR proteins (MLH1 and MSH2) were assessed using immunohistochemistry. Results: A total of 46 patients with type 1 endometrial carcinoma were analyzed. We observed MMR deficiency (dMMR) in 12 patients (26.1%) and MMR proficiency (pMMR) in 34 patients (73.9%). Of the 12 patients with dMMR, nine cases (75%) were diagnosed as stage I and 7 (58.33%) as low grade. The 3-year DFS in patients with dMMR and pMMR was 83.3% and 67.6%, respectively (Hazard Ratio 2.31, 95% CI 0.5135-10.475, p=0.27). Higher stages had a 5.42 times increased risk of recurrence (95% CI 1.3378-21.9358, p=0.018). Higher histopathological grades were also associated with 8.65 times increased risk of recurrence (95% CI 2.5020-29.8738, p=0.001). Conclusion: Patients with dMMR had a better DFS compared to those with pMMR; however, the difference was not statistically significant. The tumor stage and histopathological grade were independent risk factors for recurrence.