Therapeutic lymph node dissection in melanoma: different prognosis for different macrometastasis sites?

Background: The prognostic significance of primary tumor location, especially the poor prognosis for melanomas in the scalp and neck region, is well established. However, the prognosis for different sites of nodal macrometastasis has never been studied. This study investigated the prognostic value of the location of macrometastasis in terms of recurrence and survival rates after therapeutic lymph node dissection (TLND).
Methods: All consecutive FDG-PET-staged melanoma patients with palpable and cytologically proven lymph node metastases operated at our clinic between 2003 and 2011 were included. Disease-free survival and disease-specific survival (DSS) were compared for nodal metastases in the groin, axilla, and neck regions by multivariable analysis.
Results: A total of 149 patients underwent TLND; there were 70 groin (47 %), 57 axillary (38 %), and 22 neck (15 %) dissections. During a median follow-up of 18 (range 1-98) months, 102 patients (68 %) developed recurrent disease. Distant recurrence was the first sign of progressive disease in 78, 76, and 55 % of the groin, axilla, and neck groups, respectively (p = 0.26). Low involved/total lymph nodes (L/N) ratio (p < 0.001) and absence of extranodal growth pattern (p = 0.05) were independent predictors of a longer disease-free survival. For DSS, neck site of nodal metastasis (p = 0.02) and low L/N ratio (p < 0.001) were independent predictors of long survival. The estimated 5-year DSS for the groin, axilla, and neck sites was 28, 34, and 66 %, respectively.
Conclusions: There seems significantly longer DSS after TLND for nodal macrometastases in the neck compared to axillary and groin sites, although larger series should confirm this finding.