Cervical versus endometrial injection for sentinel lymph node detection in endometrial cancer: a randomized clinical trial

Abstract

Objective: To evaluate the relationship between pelvic/para-aortic sentinel lymph node status and two different injection sites of 99m-technetium (^99mTc)-labeled phytate in patients with endometrial cancer.

Methods: This was a randomized controlled trial involving 81 patients with endometrial cancer. In the cervical group (n=40), injections of ^99mTc were performed at the 3 and 9 o'clock positions of the uterine cervix. In the endometrial group (n=41), ^99mTc was injected into the fundal endometrium using a transcervical catheter. Sentinel lymph nodes were detected through pre-operative lymphoscintigraphy and intra-operatively using a handheld gamma probe. All patients underwent complete pelvic and para-aortic lymphadenectomy procedures. Pathologic ultra-staging was performed with immunostaining for cytokeratin in sentinel lymph nodes after routine hematoxylin and eosin histological examinations. The primary endpoint was the estimation of detection rates, sensitivity, false-negative rates, negative predictive value, and analysis of the distribution of pelvic and para-aortic sentinel lymph nodes.

Results: The rate of detection of at least one sentinel lymph node, sensitivity, and the negative predictive value was 80%, 66.6%, 96.6% for the cervical group and 85%, 66.6%, 96.9% for the endometrial group, respectively. False-negative sentinel lymph nodes were detected in one patient from each group . There was no significant difference between the groups in terms of total sentinel lymph node count, sentinel pelvic lymph node count, and pelvic bilaterality, but the para-aortic sentinel lymph node count was significantly higher in the endometrial group (p<0.001). Ultra-staging examination of the pelvic sentinel lymph nodes revealed isolated tumor cells in one patient from each group.

Conclusion: Transcervical endometrial tracer injection in endometrial cancer revealed similar pelvic but significantly higher para-aortic sentinel lymph node detection.

Keywords: endometrial neoplasms; lymphatic metastasis; sentinel lymph node.