Final Report From Multicenter Selective Lymphadenectomy Trial Supports Sentinel-Node Biopsy for Thick and Intermediate-Thickness Melanomas
The 10-year follow-up of the Multicenter Selective Lymphadenectomy Trial (MSLT), reported in The New England Journal of Medicine by Morton et al in the MSLT Group, provides support for use of sentinel-node biopsy for thick melanomas, as well as for intermediate-thickness melanomas. Current guidelines recommend use of sentinel-node biopsy for patients with intermediate-thickness melanomas and consideration of the procedure for patients with thick melanomas.
Study Details
In the MSLT, patients with primary cutaneous melanomas were randomly assigned to undergo wide excision and nodal observation with lymphadenectomy for nodal relapse (observation group) or wide excision and sentinel-node biopsy with immediate lymphadenectomy for nodal metastases detected on biopsy (biopsy group). The per-protocol analysis included 1,270 patients with intermediate-thickness melanomas (1.20–3.50 mm; 770 in the biopsy group and 500 in the observation group), 290 patients with thick melanomas (> 3.50 mm; 173 and 117), and 232 patients with thin melanomas (< 1.20 mm; 141 and 91). In the total population, 20.8% of patients had nodal metastases.
Improved Disease-Free Survival
There were no significant differences between the biopsy group and observation group in mean 10-year melanoma-specific survival among patients with intermediate-thickness melanomas (81.4% vs 78.3%, hazard ratio [HR] = 0.84, P = .18) or among patients with thick melanoma (58.9% vs 64.4%, HR = 1.12, P = .56). Mean 10-year disease-free survival was significantly improved in the biopsy group among patients with intermediate-thickness melanomas (71.3% vs 64.7%, HR = 0.76, P = .01) and among those with thick melanomas (50.7% vs 40.5%, HR = 0.70, P = .03).
The cumulative 10-year incidence of nodal metastases was 21.9% in the biopsy group and 19.5% in the observation group among patients with intermediate-thickness melanomas and 42.0% and 41.4% among those with thick melanomas. Among all patients, mean 10-year melanoma-specific survival was 62.1% for those with metastasis vs 85.1% for those without metastasis (HR = 3.09, P < .001) among patients with intermediate-thickness melanomas and 48.0% vs 64.6% (HR = 1.75, P = .03) among those with thick melanomas. In a multivariate analysis, positive vs negative sentinel-node status was the strongest predictor of disease recurrence (HR = 2.64, P < .001) or death from melanoma (HR = 2.40, P < .001).
Survival With Nodal Metastases
Mean 10-year melanoma-specific survival was significantly improved in the biopsy group (62.1% vs 41.5%, HR = 0.56, P = .006) among patients with nodal metastases from intermediate-thickness melanomas but not among patients with nodal metastases from thick melanomas (48.0% vs 45.88%, HR = 0.92, P = .78). There were no differences between the two groups in melanoma-specific survival for patients without nodal metastasis among either patients with intermediate-thickness melanomas or those with thick melanomas.
Distant disease-free survival was significantly improved in patients with nodal metastases from intermediate-thickness melanomas who received immediate vs delayed lymphadenectomy (HR = .62, P = .02), but no benefit was observed among those with metastases from thick melanomas (HR = 0.96, P = .88).
The investigators concluded, “Biopsy-based staging of intermediate-thickness or thick primary melanomas provides important prognostic information and identifies patients with nodal metastases who may benefit from immediate complete lymphadenectomy. Biopsy-based management prolongs disease-free survival for all patients and prolongs distant disease-free survival and melanoma-specific survival for patients with nodal metastases from intermediate-thickness melanomas.”
Mark B Faries, MD, of the John Wayne Cancer Institute at Saint John's Health Center, is the corresponding authors for The New England Journal of Medicine article. The article was dedicated to the memory of Donald L. Morton, MD, who died shortly before its publication.
The study was supported by the National Cancer Institute and Australia and New Zealand Melanoma Trials Group.
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