Can Ki-67 Predict Pelvic Node Status in Endometrial Adenocarcinoma?

Background: The Ki-67 marker is a nuclear protein that has a direct correlation with the degree of cells proliferation that often expressed in human neoplasm. Objective: To evaluate utilization of Ki-67 expression as predictor for pathological nodal positivity in endometrial endometrioid adenocarcinoma. Design: A retrospective case control study. Settings: Tertiary cancer center. Materials and methods: We evaluated 12 histopathological slides for patients with endometrioid adenocarcinoma of the uterus for percentage of expression of Ki-67. We defined high expression as Ki-67 stained > 50% of tumor cells. Main outcome measures: The correlation of Ki-67 high expression rates and pelvic node positivity in endometrioid adenocarcinoma. Results: Our sample mean age at diagnosis is (58.25 years) and median age is (57 years). The rate of high expression of Ki-67 in tumor cells among cases with positive lymph nodes vs controls were significantly higher (83%) vs (17%), with (p-value = 0.04). There were no significant differences between the mean age in cases and controls (59.8 vs 56.67) with (p = 0.67), tumor grade (p = 0.3), myometrium invasion (p = 0.1), cervical stromal invasion (p = 0.2), lymphovascular invasion (p = 0.2). On multivariate analysis a high expression of Ki-67 continued to be independent predictor for lymph node positivity (p= 0.02). Conclusions: This finding suggests that a high expression of Ki-67 plays an important role as predictor for lymph node positive in endometrioid adenocarcinoma. The level of expression of Ki-67 can be utilized for preoperative or postoperative risk assessment to predict for lymph node metastasis for cases with borderline indications for postoperative pelvic irradiation. Further prospective larger study is needed to validate this preliminary data.