Introduction/Background Molecular classification of endometrial cancer is the standard of referencing for early stage disease and takes precedence over standard pathology concerning the decision to proceed with adjuvant treatment. Several studies evaluated its impact on survival outcomes of endometrial cancer patients and in the present prospective cohort we evaluate the corelation of microsatellite instability (MSI) with standard pathology features of the disease.

Methodology The study is based in a consecutive cohort of patients. All the pathological features were retrieved and an analysis of microsatellite instability was performed with the assessment of MLH1, PMS2, MSH2 and MSH6. Correlation analysis was performed concerning the size of tumor, depth of myometrial invasion, distance from myometrial serosa, stage of disease and presence of lymphovascular space invasion.

Results Overall, 66 patients were retrieved of whom 47 (71%) presented with early-stage disease and 19 (29%) had advanced stage disease. Mean patient age was 62 years (37–83). Microsatellite instability was observed in 23 patients (34.8%). Neither tumor volume, nor the depth of myometrial invasion correlated with the presence of MSI. Positive lymph nodes and lymphovascular space invasion were significantly more prevalent in patients with MSI (p=.016, p=.042). Omental metastases did not differ among the two groups.

Conclusion Microsatellite instability is associated with lymphovascular space invasion and lymph node metastases. These findings explain the increased recurrence rates and decreased overall survival observed by other researchers and should be taken into account during the preoperative assessment and postoperative follow-up of patients.

Disclosures No conficts of interest. The present study was not funded.