Accuracy of sentinel lymph node detection following intra-operative cervical injection for endometrial cancer: A prospective study

Objective: The objective of this study is to evaluate the detection rate and diagnostic accuracy of sentinel lymph node (SLN) mapping using intra-operative cervical injection of filtered 99mTc-sulfur colloid (99mTc-SC) and patent blue in patients with endometrial cancer. Methods: Prospective evaluation of the first 100 endometrial cancer patients undergoing SLN mapping using cervical injection of patent blue combined with filtered 99mTc-SC in the operating room was done. Patients underwent robotic-assisted lymphatic mapping with frozen section, hysterectomy, BSO, and completion bilateral lymphadenectomy (including para-aortic nodes in grade 2 and 3 tumors). Results: At least one SLN was detected in 92% of patients; in 66 of these (72%) bilateral SLN were detected, and in 15 cases the SLN was in the para-aortic area. Eleven percent of all patients had lymph node metastases, and 4 of which had pre-operative grade 1 tumor. The SLN was the only positive node in 44% of the cases with positive nodes. Sensitivity was 89% with 1 false negative result, yielding a negative predictive value of 99% (95% CI 93-100). Specificity was 100% (95% CI 94-100), and positive predictive value was 100% (95% CI 60-100). No complications or anaphylactic reactions were noted. Conclusions: Intra-operative SLN biopsy, using cervical injection of patent blue and filtered 99mTc-SC in endometrial cancer patients is feasible and yields adequate detection rates.