Completion Lymph Node Dissection for Melanoma Before and After the Multicenter Selective Lymphadenectomy Trial-II in the United States

Background: The Multicenter Selective Lymphadenectomy Trial-II (MSLT-II) revealed completion lymph node dissection (CLND) after positive sentinel lymph node biopsy (SLNB) did not improve melanoma-specific survival compared with surveillance. Given these findings and the morbidity associated with CLND, this study investigated trends in rates and predictors of CLND after MSLT-II. Methods: Analysis of the National Cancer Database was performed for all patients aged ≥18 years with melanoma and a positive SLNB for 2012–2019. Rates of CLND before and after publication of MSLT-II were identified and logistic regression used to identify factors associated with CLND. Results: Patients undergoing CLND declined from 55.9% pre-MSLT-II (n = 9725) to 19.5% post-MSLT-II (n = 9419) (odds ratio [OR] 0.32, 95% confidence interval [CI] 0.29–0.35). CLND was less likely in females (OR 0.83; 95% CI 0.78–0.89), older patients (vs. 18–39 yr; 40–64 yr OR 0.80, 95% CI 0.65–0.98; 65–79 yr OR 0.67, 95% CI 0.53–0.84; >80 yr OR 0.38, 95% CI 0.30–0.49), sicker patients (Deyo category ≥2 OR 0.85, 95% CI 0.73–0.99), thinner primary lesions (vs. 0.01–0.79 mm; 1.01–4.00 mm OR 1.16, 95% CI 1.01–1.33; ≥4.01 mm OR 1.31, 95% CI 1.08–1.59), patients from metro areas (Rural OR 1.31, 95% CI 1.00–1.70; Urban OR 1.15, 95% CI 1.03–1.29), and those treated at lower-volume centers (vs. lowest-volume; highest-volume OR 1.31, 95% CI 1.14–1.50; high-volume OR 1.40, 95% CI 1.24–1.57). Conclusions: MSLT-II has impacted clinical care; however, male gender, thicker lesions, rural/urban residence, younger age, fewer comorbidities, and treatment at higher-volume centers confer a greater likelihood of undergoing CLND. Further investigations should focus on whether these populations benefit from more aggressive surgical care.