Patterns of recurrence and survival after lymphadenectomy in melanoma patients: clarifying the effects of timing of surgery and lymph node tumor burden.

BACKGROUND: Melanoma patients with lymph node (LN) metastases have variable survival after lymphadenectomy. This study investigates whether lymphadenectomy at different times in the course of disease progression influences disease-free survival (DFS; time from primary diagnosis to first recurrence after lymphadenectomy), post recurrence survival (PRS; time from first recurrence after lymphadenectomy to death), and overall survival (OS; time from diagnosis to death).

METHODS: Between 1992 and 2010, a total of 1,704 patients underwent lymphadenectomy; 502 underwent immediate completion lymphadenectomy (ICL) after positive sentinel node biopsy (SNB), 214 had delayed completion lymphadenectomy (DCL) for regional recurrence after positive SNB with no ICL or after an earlier false-negative SNB, 709 had no SNB and later required delayed therapeutic lymphadenectomy (DTL) for clinically evident metastasis, and 279 had immediate therapeutic lymphadenectomy (ITL) for clinically positive LNs at primary melanoma diagnosis.

RESULTS: Median DFS for ICL, DCL, DTL, and ITL was 68, 48, 82, and 16 months, respectively (p < 0.001). Median PRS for ICL, DCL, DTL, and ITL was 14, 8, 9, and 9 months, respectively (p < 0.001). Median OS for ICL was not reached whilst for DCL, DTL, and ITL it was 71, 101, and 29 months, respectively (p < 0.001). Extranodal spread and tumor, node, metastasis classification system N stage were the only significant prognostic factors for OS within each group. ICL patients had significantly improved DFS (p = 0.005) and OS (p = 0.012) beyond 5 years compared to DTL patients.

CONCLUSIONS: Variable outcomes after lymphadenectomy were observed with different timing of surgery and LN tumor burden. ICL patients had the best outcome.