Use of the sentinel node procedure to stage endometrial cancer

Background: Lymph node status is a major prognostic factor and a criterion for adjuvant therapy in endometrial cancer. The sentinel lymph node (SN) procedure has emerged as a possible alternative to systematic lymphadenectomy. The aims of this study were to determine the detection rate and the false-negative rate of the SN procedure, and its contribution to the staging of women with endometrial cancer. Methods: Forty-six patients with endometrial cancer underwent the sentinel node procedure followed by pelvic lymphadenectomy. SNs were detected with a dual or single labelling method in 39 and 7 cases, respectively. All SNs were analysed by both hematoxylin and eosin (H&E) staining and immunochemistry. Results: SNs were identified in 40 patients (87%), whose mean number of SN was 2.6 (range 1-5). The SN detection rate was significantly lower with the single label than with the dual label (p = 0.01). Ten women (25%) had a positive SN on final histology (i.e. there were no false negatives). A correlation was observed between lymph node involvement and both histological grade (p = 0.01) and lymphovascular space involvement (p = 0.001). The stage predicted by magnetic resonance (MR) imaging correlated poorly with the Federation International of Gynaecology and Obstetrics (FIGO) stage. Among the ten women with a positive SN, three of the four women with a grade 1 tumour at biopsy had grade 2-3 disease on final histology. Seven of the ten women with a positive SN underwent external pelvic radiotherapy, based solely on their SN involvement. Conclusions: The SN procedure can reliably determine lymph node status in women with endometrial cancer. Given the limited capacity of MR imaging to detect myometrial invasion, and of biopsy to determine histological grade, our results support the systematic use of the SN procedure in women with endometrial cancer, including those with presumed early-stage disease and/or well-differentiated tumours.