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.