MELF Pattern for Predicting Lymph Node Involvement and Survival in Grade I-II Endometrioid-type Endometrial Cancer

The aim of this study was to examine the associations between microcystic, elongated, and fragmented (MELF) pattern and other prognostic factors and lymph node involvement, disease-free survival, and overall survival (OS) using a case-control group consisting of grade I-II endometrioid endometrial carcinoma (EEC) patients with/without lymph node involvement. The files of the patients were searched electronically for all hysterectomy specimens with a diagnosis of grade I-II EEC of the uterine body from January 1, 2008 to July 31, 2014. Lymph node involvement was detected in 27 patients who were histologically diagnosed with grade I-II EEC, and these patients made up the case group. Using a dependent random sampling method, 28 grade I-II EEC patients without lymph node involvement were selected. According to multivariate regression analysis, lymphovascular space invasion [odds ratio, 23.5; 95% confidence interval (CI), 2.4-223.5] and MELF pattern (odds ratio, 13.3; 95% CI, 1.4-121.8) were significant predictors of lymph node involvement. There was recurrence in 15.8% of cases that showed a MELF pattern and in 19.4% of those that did not (P=0.738). According to Kaplan-Meier analysis, the MELF pattern revealed no significant differences in disease-free survival (hazard ratio, 1.0; 95% CI, 0.1-36.5), whereas the effect on OS was significant (hazard ratio, 2.2; 95% CI, 1.3-4.2). The presence of MELF pattern was a substantial risk factor for detecting lymph node involvement in patients with grade I-II EEC. The MELF pattern may be important for identifying which patients need staging surgery, in addition to its effect on the OS.