Prospective validation of an intraoperative algorithm to guide surgical staging in early endometrial cancer.

OBJECTIVES: Prospectively validate an intraoperative surgical staging algorithm to stratify patients with early endometrial cancer by risk of lymph node metastasis. METHODS: Subjects with endometrial cancer clinically confined to the uterus were prospectively enrolled at an academic cancer center between Jan 2012 and Jun 2015. Study participants were stratified intraoperatively into two groups based on risk of nodal involvement using cell type, tumor grade, myometrial invasion, and tumor size in accordance with an established protocol from the Mayo Clinic. Low risk (LR) subjects received extrafascial hysterectomy with bilateral salpingo-oophorectomy; high risk (HR) patients received complete surgical staging including bilateral pelvic and para-aortic lymphadenectomy. RESULTS: Of the 200 subjects enrolled, 194 were eligible for analysis. The algorithm identified 132 (68%) HR and 62 (32%) LR cancers. Of the HR subjects, 126 had lymphadenectomy performed with 14 (11%) positive for nodal metastases. Five HR subjects experienced disease recurrence. Of the 62 LR cancers, two patients developed disease recurrence. Ten LR cancers were upgraded to HR on final pathology due to lesion size (6) and grade (4). None of these patients experienced disease recurrence. The algorithm demonstrated 90% sensitivity (18/20) and 36% specificity (62/174) as determined by positive lymph nodes and/or disease recurrence. CONCLUSIONS: Intraoperative assessment of early endometrial cancer can be used to determine the extent of surgical staging. The studied algorithm has low specificity and modifications are necessary to better match the surgical procedure to the risk of metastatic cancer.