The prognostic significance of non-sentinel lymph node metastasis in cutaneous and acral melanoma patients—A multicenter retrospective study

Background:Whether non-sentinel lymph node(SLN)-positive melanoma patients can benefit from completion lymph node dissection(CLND)is still unclear.The current study was performed to identify the prognostic role of nonSLN status in SLN-positive melanoma and to investigate the predictive factors of non-SLN metastasis in acral and cutaneous melanoma patients.Methods:The records of 328 SLN-positive melanoma patients who underwent radical surgery at four cancer centers from September 2009 to August 2017 were reviewed.Clinicopathological data including age,gender,Clark level,Breslow index,ulceration,the number of positive SLNs,non-SLN status,and adjuvant therapy were included for survival analyses.Patients were followed up until death or June 30,2019.Multivariable logistic regression modeling was performed to identify factors associated with non-SLN positivity.Log-rank analysis and Cox regression analysis were used to identify the prognostic factors for disease-free survival(DFS)and overall survival(OS).Results:Among all enrolled patients,220(67.1%)had acral melanoma and 108(32.9%)had cutaneous melanoma.The 5-year DFS and OS rate of the entire cohort was 31.5%and 54.1%,respectively.More than 1 positive SLNs were found in 123(37.5%)patients.Positive non-SLNs were found in 99(30.2%)patients.Patients with positive non-SLNs had significantly worse DFS and OS(log-rank P<0.001).Non-SLN status(P=0.003),number of positive SLNs(P=0.016),and adjuvant therapy(P=0.025)were independent prognostic factors for DFS,while non-SLN status(P=0.002),the Breslow index(P=0.027),Clark level(P=0.006),ulceration(P=0.004),number of positive SLNs(P=0.001),and adjuvant therapy(P=0.007)were independent prognostic factors for OS.The Breslow index(P=0.020),Clark level(P=0.012),and number of positive SLNs(P=0.031)were independently related to positive non-SLNs and could be used to develop more personalized surgical strategy.Conclusions:Non-SLN-positive melanoma patients had worse DFS and OS even after immediate CLND than those with non-SLN-negative melanoma.The Breslow index,Clark level,and number of positive SLNs were independent predictive factors for non-SLN status.