Finding the sentinel lymph node in early cervical cancer: When is unusual not uncommon?

To report our institutional experience with sentinel lymph node (SLN) detection using indocyanine green for cervical cancer, in terms of detection rates, detection of SLN at unusual locations, and factors associated with unusual SLN locations. In addition, we performed a systematic review of the literature to identify factors associated with unusual SLN localizations.

This is a retrospective cohort study of women with early-stage cervical cancer undergoing sentinel lymph node mapping between 2015 and 2019. Outcome measures were SLN detection rates, detection rates of unusual locations for SLN and risk factors for aberrant lymphatic drainage pathways. In addition, studies evaluating factors associated with unusual SLN locations in cervical cancer were assessed in a systematic review.

A total of 100 patients were included. The unilateral SLN detection rate was 88%, whereas the bilateral detection rate was 75%. In 37% of all patients, SLN were found in unusual locations, and in 10% of patients SLN were solely found in unusual locations. Body mass index (BMI) was associated with finding SLN in unusual locations, with unusual nodes detected in 52% of patients with BMI <25 kg/m² and in 28% of patients with BMI ≥25 kg/m². The systematic review identified three studies, identifying lower BMI, nulliparity and tumor size of >20 mm as factors associated with finding SLN at unusual locations.

Aberrant drainage sites represent a significant proportion of SLN detected in cervical cancer. Factors associated with increased rates of unusual nodal locations are a lower BMI, with a possible association with nulliparity and tumor size of >20 mm.