Prediction of final pathology depending on preoperative myometrial invasion and grade assessment in low-risk endometrial cancer patients: A Korean Gynecologic Oncology Group ancillary study.

OBJECTIVES: Fertility-sparing treatment (FST) might be considered an option for reproductive patients with low-risk endometrial cancer (EC). On the other hand, the matching rates between preoperative assessment and postoperative pathology in low-risk EC patients are not high enough. We aimed to predict the postoperative pathology depending on preoperative myometrial invasion (MI) and grade in low-risk EC patients to help extend the current criteria for FST. METHODS/MATERIALS: This ancillary study (KGOG 2015S) of Korean Gynecologic Oncology Group 2015, a prospective, multicenter study included patients with no MI or MI <1/2 on preoperative MRI and endometrioid adenocarcinoma and grade 1 or 2 on endometrial biopsy. Among the eligible patients, Groups 1-4 were defined with no MI and grade 1, no MI and grade 2, MI <1/2 and grade 1, and MI <1/2 and grade 2, respectively. New prediction models using machine learning were developed. RESULTS: Among 251 eligible patients, Groups 1-4 included 106, 41, 74, and 30 patients, respectively. The new prediction models showed superior prediction values to those from conventional analysis. In the new prediction models, the best NPV, sensitivity, and AUC of preoperative each group to predict postoperative each group were as follows: 87.2%, 71.6%, and 0.732 (Group 1); 97.6%, 78.6%, and 0.656 (Group 2); 71.3%, 78.6% and 0.588 (Group 3); 91.8%, 64.9%, and 0.676% (Group 4). CONCLUSIONS: In low-risk EC patients, the prediction of postoperative pathology was ineffective, but the new prediction models provided a better prediction.

Preoperative assessment of lymph node metastasis in endometrial cancer: A Korean Gynecologic Oncology Group study.

BACKGROUND: Previously proposed criteria for preoperatively identifying endometrial cancer patients at low risk for lymph node metastasis remain to be verified. For this purpose, a prospective, multicenter observational study was performed. METHODS: Eligible patients with histologically confirmed endometrial cancer underwent magnetic resonance imaging (MRI) and serum cancer antigen 125 (CA 125) testing before surgery. The following criteria were used to identify low-risk patients: 1) endometrioid-type cancer, 2) no evidence of deep myometrial invasion on MRI, 3) no enlarged lymph nodes on MRI, 4) no suspicious metastasis out of the uterine corpus, and 5) serum CA 125 levels less than 35 U/mL. Systematic pelvic and/or para-aortic lymphadenectomy was performed for all patients. The primary endpoint was estimation of the negative predictive value (NPV). RESULTS: From January 2012 to December 2014, 529 patients from 20 hospitals in 3 Asian countries were consecutively enrolled. According to our criteria, 272 patients (51.4%) were categorized into the low-risk group. Fifty-three of the 529 patients (10.0%) had lymph node metastases; these patients included 8 (2.9%) falsely categorized as low-risk. The sensitivity and specificity of the criteria were 84.9% and 55.5%, respectively. The NPV of 97.1% was higher than the predefined target endpoint of 96%. CONCLUSIONS: The low-risk criteria based on preoperative tests were confirmed to be reliable and accurate for identifying patients at low risk for lymph node metastasis. These criteria may facilitate patient counseling and surgical decision making. Cancer 2017;123:263-272. © 2016 American Cancer Society.