Evaluating Variation in Lymph Node Sampling During Sentinel Lymph Node Biopsy for Melanoma

The operative standard for melanoma, implemented by the Commission on Cancer (CoC), addresses margin width and excision depth, but does not collect information on sentinel lymph node biopsy (SLNB). However, SLNB, an implemented technical standard in breast cancer, is also critical in the management of melanoma through its impact on nodal staging. This study aimed to characterize the current facility-level variation in nodal yield and nodal positivity to determine if there is an opportunity for improvement through standardization.

Using the National Cancer Database, we identified patients with T1b-T4 melanoma of the trunk and upper extremities who underwent SLNB from 2018 to 2022. Reliability-adjusted estimates for nodal yield and nodal positivity were calculated using Poisson regression and logistic regression with random intercepts for hospitals.

We identified 48,653 melanoma patients from 1167 facilities. SLNB median nodal yield was 2.4 (IQR 2.2-2.7), ranging from 1.4 to 7.0. SLNB median nodal positivity was 18.0% (IQR 17.1-19.5%), ranging from 11.6 to 40.5%. A weak correlation between nodal yield and nodal positivity was observed (Spearman correlation coefficient = 0.08, p = 0.009).

Facility-level variation in nodal yield was minimal and weakly correlated with nodal positivity. This suggests that SLNB performed for melanoma of the trunk and upper extremities is well standardized across CoC hospitals in the absence of a defined operative standard. Future efforts to improve the quality of melanoma nodal surgery may be best focused on technical elements of other procedures, such as lymphadenectomy or more novel lymph node dissection approaches following neoadjuvant therapy.