Empty node packet in endometrial cancer: predictors and clinical significance in the sentinel lymph node era

This study aimed to evaluate clinical and pathological factors associated with the occurrence of empty node packets during sentinel lymph node mapping in patients with endometrial cancer.

We performed a retrospective cohort study including patients with histologically confirmed endometrial carcinoma who underwent sentinel lymph node mapping between November 2012 and December 2023. An empty node packet was defined as the intra-operative removal of a presumed sentinel node with no lymphoid tissue identified on final pathological examination. Logistic regression models were used to identify independent predictors.

Of 489 patients who had sentinel lymph node mapped, 23 (4.7%) had an empty node packet. In the univariate analysis, body mass index and myometrial invasion were significantly associated (p < .05). In the multi-variable analysis, only body mass index remained independently associated (odds ratio 1.075, 95% confidence interval 1.01 to 1.14, p = .022) with an empty node packet. Tumor histology, grade, type of tracer, and surgical approach were not associated. No nodal recurrences occurred in patients with an empty node packet.

Empty node packets are uncommon but clinically relevant during sentinel lymph node mapping for endometrial cancer. Higher body mass index was the only independent predictor, underscoring the influence of patient-related factors on mapping accuracy.