The Evaluation of Sentinel Lymph Node Biopsy Using Radiocolloid in First Stage Endometrial Cancer

Detection of a sentinel lymph node (SLN) in patients with endometrial cancer (EC) reduces the rate of unnecessary systemic lymph dissection. The aim of this study was to assess the SLN detection rate, accuracy of the method using Tc-99m-SENTI-SCINT and the rate of metastatic nodal involvement in patients with preoperative first stage EC.

A prospective study of SLN biopsy of 41 patients with stage I EC was conducted after cervical application of 4mCi Tc-99m-SENTI-SCINT. Planar lymphoscintigraphy and single-photon emission computed tomography/computed tomography (SPECT/CT) of the pelvis were performed, followed by site-specific lymphadenectomy in intermediate-risk patients if no SLN was detected per hemipelvis and pelvic lymphadenectomy in all high-risk patients.

Pre-operative detection rate of planar lymphoscintigraphy was 80.49 [95% confidence interval (CI): 68.36-92.62] and of SPECT/CT 95.12 (95% CI: 88.52-101.7). The total intraoperative SLN detection rate was 95.12 (95% CI: 88.52-101.7) per patient and 26.83 (95% CI: 19.91-33.75) bilaterally. The average number of SLNs removed was 1.6±0.8. The most common anatomical location of SLN was the right external iliac region. The SLN metastatic rate was 17%. Both sensitivity and negative predictive value regarding metastatic involvement were 100%.

The SLN detection rate, sensitivity and negative predictive value using Tc-99m-SENTI-SCINT in patients with EC in our study were high. The application of ultra-staging in the histopathological analysis of SLN increases the detection of nodal metastases and improves the staging in these patients.