Subserosal uterine injection of blue dye for the identification of the sentinel node in patients with endometrial cancer: a feasibility study

To define the detection rate, sensitivity, and negative predictive value (NPV) of the sentinel node technique in patients with endometrial cancer. Patients with endometrial cancer after informed consent underwent subserosal injection of blue dye during hysterectomy in a tertiary gynae/oncology department between 2010 and 2014. The procedure was performed in all cases by the same team including two gynae/oncologist consultants and one trainee. All relevant perioperative clinicopathological characteristics of the population were recorded prospectively. The identified sentinel nodes were removed separately and a completion bilateral pelvic lymphadenectomy followed in all cases. Simple statistics were used to calculate the sensitivity and NPV of the method on per patient basis. Fifty-four patients were included in this study. At least one sentinel node was mapped in 46 patients yielding a detection rate of 85.2%. Bilateral detection of sentinel nodes was accomplished in only 31 patients (57.4%). The mean number of sentinel nodes was 2.6 per patient and the commonest site of identification was the external iliac artery and vein area (66%). Six patients (11%) had a positive lymph node, and in five of them, this was the sentinel one yielding a sensitivity of 83.3% and an NPV of 97.5%. The overall detection rate improved significantly after the first 15 cases; however, this was not the case for the bilateral detection rate. Our study is in accordance with previous studies of sentinel node in endometrial cancer and further demonstrates and enhances the confidence in the technique. In the current era of an ongoing debate on whether a systematic lymphadenectomy in patients with endometrial cancer is still necessary, we believe that the sentinel node is an acceptable alternative and should be applied routinely in tertiary centres following a strict algorithm.