Purpose: We investigated whether the nonsentinel lymph node (NSLN) status in patients with melanoma improves the prognostic accuracy of common staging features; then we formulated a proposal for including the NSLN status in the current melanoma staging system.
Patients and methods: We retrospectively collected the clinicopathologic data of 1,538 patients with positive SLN status who underwent completion lymph node dissection (CLND) at nine Italian centers. Multivariable Cox regression survival analysis was used to identify independent prognostic factors. Literature meta-analysis was used to summarize the available evidence on the prognostic value of the NSLN status in patients with positive SLN.
Results: NSLN metastasis was observed in 353 patients (23%). After a median follow-up of 45 months, NSLN status was an independent prognostic factor for melanoma-specific survival (hazard ratio [HR] = 1.34; 95% CI, 1.18 to 1.52; P < .001). NSLN status efficiently stratified the prognosis of patients with two to three positive lymph nodes (n = 387; HR = 1.39; 95% CI, 1.07 to 1.81; P = .013), independently of other staging features. Searching the literature, this patient subgroup was investigated in other two studies. Pooling the results (n = 620 patients; 284 NSLN negative and 336 NSLN positive), we found that NSLN status is a highly significant prognostic factor (summary HR = 1.59; 95% CI, 1.27 to 1.98; P < .001) in patients with two to three positive lymph nodes.
Conclusion: These findings support the independent prognostic value of the NSLN status in patients with two to three positive lymph nodes, suggesting that this information should be considered for the routine staging in patients with melanoma.