Predictive factors of preoperative sentinel lymph node detection in intermediate and high-risk endometrial cancer

BACKGROUND: In endometrial cancer (EC), sentinel lymph node (SLN) mapping has emerged as an alternative to systematic lymphadenec-tomy. Little is known about factors that might influence SLN preoperative detection. The aim of our study was to evaluate the clinical and techni-cal variables that may influence on the success of SLN detection in preoperative lymphatic mapping in patients with intermediate and high-risk EC when performing transvaginal ultrasound-guided myometrial injection of radiotracer (TUMIR).METHODS: Between March 2006 and March 2017, we prospectively enrolled patients with histologically confirmed EC with intermediate or high-risk of lymphatic involvement. All women underwent SLN detection by using TUMIR approach. After radiotracer injection, pelvic and abdominal planar and SPECT/CT images were acquired to obtain a preoperative lymphoscintigraphic mapping. Pattern of drainage was regis-tered and analyzed to identify the factors directly involved in drainage. Sonographer learning curves to perform TUMIR approach were created following Cumulative Sum and Wright methods. Univariate and multivariate analyses were performed using logistic regression.RESULTS: During study period, 123 patients were included. SLN preoperative detection rate was 70.7%. Age under 75 years at diagnosis (P<0.01), radiotracer injection above 4 mL -high-volume-(P<0.01), and tumoral size below 2 cm (P=0.04) were associated with higher SLN preoperative detection rate. Twenty-five procedures were necessary to attain an adequate performance in TUMIR approach.CONCLUSIONS: The higher SLN preoperative detection rate in women with intermediate and high-risk endometrial cancer after TUMIR ap-proach was related with younger age, smaller tumors and high-volume injection of radiotracer. Sonographers are required to perform 25 proce-dures before acquiring an expertise in radiotracer injection.

Automated summary

A study on preoperative lymphatic mapping in patients with intermediate and high-risk endometrial cancer found that younger age, high-volume injection of radiotracer (above 4 mL), and smaller tumor size were associated with a higher success rate of sentinel lymph node preoperative detection.