National Practice Patterns of CLND for Sentinel Node-Positive Melanoma

Background: Melanoma incidence is increasing faster than any other malignancy. Melanoma may spread to the lymph nodes, but early detection and treatment improves melanoma-specific survival. Spread to the regional lymph nodes is tested with a sentinel lymph node (SLN) biopsy. Current recommended management of a positive SLN biopsy is removal of the remaining lymph nodes with a completion lymph node dissection (CLND). However, recent evidence suggests close observation may be an appropriate alternative to CLND for patients with low SLN disease burden. In addition, a multi-institutional randomized trial is currently investigating the necessity of CLND in select patients with low SLN disease burden. We examined current practice patterns and factors associated with the utilization of CLND in patients with sentinel-node positive melanoma, particularly those with low SLN disease burden. Methods: The National Cancer Database (NCDB) collects demographic, staging, treatment, and oncologic outcomes data from over 1,500 Commission on Cancer (CoC)-accredited hospitals capturing approximately 70% of newly diagnosed cancer cases in the United States. Using the NCDB, we examined use of CLND in SLN positive patients ≥ 18 years and diagnosed with stage I-III melanoma in 2013 or 2014. Multivariable logistic regression models were developed to examine factors associated with CLND utilization after a positive SLN biopsy. Results: Of the 38,176 patients identified, 51.4% (19,610) received a SLN biopsy and 8.6% (1,677) were found to have at least one positive SLN. Over half of the patients with a positive SLN biopsy underwent a CLND (58.9%; 988). Over two-thirds (70.7%; 699) of these patients underwent the CLND during a subsequent operation. Patients less frequently underwent a CLND for a positive SLN if the primary tumor was located on the lower extremity (Odds Ratio [OR]=0.68; 95% Confidence Interval [CI] 0.51-0.92; p=0.012), were older (age 76-85 OR=0.48; 95% CI 0.31-0.74; p < 0.001 and age ≥ 86 OR=0.33; 95% CI 0.17-0.66; p=0.002), or were treated at a hospital with low melanoma-specific surgical volume (<13 cases per year; OR=0.57; 95% CI 0.42-0.77; p<0.001). In subgroup analysis limited to patients with only 1 positive SLN on final pathology (i.e., to assess management of those with low nodal disease burden), the same four factors (lower extremity [OR = 0.61; 95% CI 0.43-0.86; p=0.005], age 76-85 [OR=0.50; 95% CI 0.30-0.84; p=0.008], age ≥ 86 [OR=0.35; 95% CI 0.15-0.79; p=0.011], and lowest hospital volume [OR=0.58; 95% CI 0.41-0.83; p=0.003] were associated with a lower likelihood of undergoing a CLND. Conclusions: CLND was performed in 58.9% of SLN-positive melanoma patients. As growing evidence supports close observation in selected patients with low nodal disease burden, improved surveillance measures are needed to ensure that CLND is withheld in the correct patient population, but still offered to patients with more than minimal nodal disease burden.