The Role of Completion Lymphadenectomy in Positive Regional Lymph Nodes in Melanoma: A Meta-analysis

Background: The optimal management of melanoma with positive sentinel lymph node (SLN) remains unclear. Completion lymph node dissection (CLND) only yields additional positive non-SLN in 20% of cases and its benefits on survival remains debatable. Methods: An online database search of Medline was performed; key bibliographies were reviewed. Studies comparing outcomes after CLND versus observation were included. Odds ratios (ORs) with the corresponding 95% confidence intervals (CIs) by random fixed effects models of pooled data were calculated. The primary endpoints were disease-free survival (DFS), melanoma-specific survival (MSS), and overall survival (OS). Results: Search strategy yielded 117 publications. Twelve studies were selected for inclusion, comprising 7966 SLN-positive patients. Among these patients, 5306 (66.6%) subjects underwent CLND and 2660 (33.4%) patients were observed. Median Breslow thickness and ulceration were similar between groups (2.8 ± 0.6 mm versus 2.5 ± 0.8 mm, P = 0.721; and 38.8% versus 37.2%, P = 0.136, CLND versus observation, respectively). CLND was associated with statistically significant improved 3-y (71.0% versus 66.2%, OR 0.82, 95% CI 0.69-0.97, P = 0.02) and 5-y DFS (48.3% versus 47.8%, OR 0.75, 95% CI 0.59-0.96, P = 0.02) compared with observation. However, no difference was demonstrated in 3-y MSS (83.7% versus 84.7%, OR 1.09, 95% CI 0.88-1.35, P = 0.41), 5-y MSS (68.4% versus 69.8%, OR 1.02, 95% CI 0.88-1.19, P = 0.78), or OS (68.2% versus 78.9%, OR 0.93, 95% CI 0.55-1.57, P = 0.78). Conclusions: Based on this large-scale analysis, CLND improved both 3- and 5-y DFS, possibly because of increased rates of local control; however, this did not translate in improved MSS or OS. Efforts toward the identification of molecular markers associated with poor outcomes in SLN-positive patients who undergo observation are warranted.