Materials and Methods
The data of 1294 consecutive patients who underwent primary surgical treatment for EC between 2003 and 2018 were retrieved from the computerized database at Hacettepe University Hospital, Turkey included to this study. A total of 258 patients were diagnosed as IR and HIR EC using the ESMO-ESGO-ESTRO classification were identified and their datas were retrospectively reviewed 8. These criteria are related three pathological risk factors including grade 2 or 3 histology, the presence of LVSI and deep myometrial invasion. The patients were considered as IR as if they have; endometrioid histology with myometrial invasion <50% and histological grade 3; or myometrial invasion ≥50% and grades 1–2; or cervical involvement and grades 1–2. And patients were accepted as HIR if they have: age above 70 years with a risk factor, age between 50 and 69 years with two, and age above 18 years with three risk factors.
All patients underwent total hysterectomy and bilateral salphingoopherectomy (TH+BSO), peritoneal washing and pelvic ± para-aortic lymph node dissection (LND) was performed in selected cases. Patients were divided into two groups up to performing LND. Patients with non-endometrioid histology, synchronous epithelial ovarian cancer, patients who had undergone sentinel lymph node procedure, missing medical and pathological report were excluded from the study. It was described as adequate at least 10 lymph nodes for pelvic LND, and 5 lymph nodes for para-aortic LND. Patients were categorized according to lymph node counts, and the choice of 20 pelvic lymph nodes as the discrimination point in our study warrants further discussion. This threshold number is consistent with the mean and median number of lymph nodes removed during surgical staging in our patient population. Patients beyond these criteria were excluded from the study (Figure 1).
Collected data included patients’ age, body mass index (BMI), co-morbidities, primary tumor size, myometrial invasion (MI), histological grade, LVSI, stage of primary EC, the surgical procedure, adjuvant treatments, date of diagnosis, date of last follow-up or death, date of disease recurrence and its’ localizations. BMI was defined as the body mass in kilograms divided by the square of the body height in meters. Co-morbidities were consist of hypertension, diabetes, cardiovascular, and pulmoner diseases. The largest diameter of the tumor considered as primary tumor size. The surgical specimens were examined by gynecologic pathologists, and the grading was determined by standard FIGO criteria. LVSI is defined as the presence of tumor in lymphatic and/or vascular spaces within the uterine myometrium12. All tumors were staged according to the revised 2009 FIGO staging system.
SPSS (Statistical Package for Social Sciences for Windows, Armonk, NY: IBM Corp.) version 22.0 was used for the recording and analysis of data. Correlation of variables between groups was assessed using Chi-square or Fisher Exact test in the case of categorical data and using the Student t-test for quantitative variables. Survival probability was studied by the Kaplan–Meier method and the equality of survival curves was tested by the log-rank test. Disease-free survival (DFS) was calculated from the date of treatment start until recurrence or death from any cause. Overall survival (OS) was defined as the time elapsed between date of diagnosis and date of death, or last follow-up. A p-value of less than 0.05 was considered to be statistically significant and all statistical tests were two-sided.
Committee permission was not sought due to the retrospective design of the study. However, all participants signed an informed consent which forgives the institution to utilize their data.