Objectives Endometrial cancer (EC) represents the most common gynecological cancer mostly diagnosed at stage I. Sentinel lymph node (SLN) arised as a valuable option to lymph node dissection. We aim to determine negative predictive value (NPV),overall and bilateral detection rates of SLN in EC stage I.

Methods This was a cross-sectional prospective study including 38 patients with EC stage I treated at Salah Azaiz Institute over a period of 34 months from March 2018 to January 2021.

Results Endometrioid adenocarcinoma was reported in 89% of cases. The pelvic MRI showed IA and IB stages in 58% and 42% of cases, respectively.The detection techniques were combined (48%), colorimetric (34%) and radioisotope (18%). Lymphoscintigraphy was conducted in 66% of women demonstrating overall, bilateral and failed detection rates of 92%, 24% and 8%, respectively. The overall, bilateral and failed intra-operative detection rates were of 76%, 37% and 24% respectively. A micrometastasis (1%) was noted among a total of 87 SLNs. False negative rate (FNR) and NPV were of 0% and 100%.Factors affecting overall detection wereinitial histologic grade (p=0.01) and tumor size on MRI (p=0.04). Final histologic grade 1 (p=0.005), 2 (p=0.002) and myometrial invasion (p=0.04) were also significant contributors.No significant factors affecting bilateral detection were set.

Conclusions FNR and NPV were of 0% and 100% similarly to previous results through literature. We aim to continue this promising protocol toward including more patients that may helps us improve our overall and bilateral detection rates.