H. Kakish1, T. Lal1, L. Rothermel1, R. Hoehn1 1University Hospitals Cleveland Medical Center, Division Of Surgical Oncology/Department Of Surgery, Cleveland, OH, USA
Introduction:
Sentinel lymph node biopsy (SLNB) is an area of debate for Lentigo Maligna Melanoma (LMM) due to the lower likelihood of nodal metastasis. The utility of SLNB and its prognostic value in LMM has not been studied with large databases.
Methods:
This is a retrospective review of the National Cancer Database (NCDB) and the Surveillance, Epidemiology, and End Results (SEER) database for clinically node negative, Breslow thickness (BT) >1.0 mm LMM patients. Multivariable logistic regression identified factors associated with sentinel lymph node biopsy (SLNB) performance and nodal positivity. Univariable and multivariable analysis assessed overall survival (OS) and melanoma-specific survival (MSS) based on SLNB.
Results:
The NCDB included 3,552 LMM patients who fit our inclusion criteria, of whom 2,365 (66.6%) underwent SLNB (versus 80.0%-84.0% in nodular, superficial spreading, and acral lentiginous tumors) and 263 (11.3%) were node-positive (versus 18.6%-34.2% in the other subtypes). The SEER cohort identified 1,233 patients, of whom 672 (54.5%) underwent SLNB and 53 (8.0%) were node-positive. Nodal positivity was independently associated with Breslow depth (>4 mm; OR= 3.8; 95% CI= 2.52-5.57), lymphovascular invasion (OR= 3.0; 95% CI= 1.81-5.02), mitosis (OR= 2.3; 95% CI= 1.28-3.99), and ulceration (OR= 1.5; 95% CI= 1.08-2.02). Age was not a significant predictor of nodal positivity. Univariable (Figure 1) and multivariable analyses showed improved OS for patients who underwent SLNB, regardless of results (positive: HR= 0.64, 95% CI= 0.55-0.76; negative: HR= 0.68; 95% CI= 0.49-0.94). However, MSS similar between non-SLNB and SLNB-negative patients, and worse only for those with positive SLNB (HR= 3.93, 95% CI= 2.09-7.37).
Conclusion:
In this study of two national cancer registries, SLNB performance and node-positivity are less common among LMM than other melanoma subtypes. While improved OS in patients undergoing SLNB may imply surgical selection bias, analysis of MSS suggests appropriate patient selection and important prognostic value associated with SLNB. These results support continued SLNB for LMM patients according to standard melanoma guidelines.
