In an analysis of the Multicenter Selective Lymphadenectomy Trial II reported in JAMA Surgery, Crystal et al found that patients with melanoma with sentinel lymph node (SLN) metastasis who were randomly assigned to observation vs completion lymph node dissection (CLND) following SLN biopsy exhibited a high rate of long-term freedom from regional recurrence.
The previously reported primary analysis of the trial showed that CLND vs observation was associated with improved regional control but not disease-specific survival (primary endpoint) at 3 years.
In the international phase III trial, patients were randomly assigned to immediate CLND or nodal observation with clinical examination and ultrasonography. The current report provides long-term findings in 855 nodal basins in 823 patients assigned to observation.
Among 855 observed basins, 80.2% (95% confidence interval [CI] = 77%–83%) were free of regional nodal recurrence at 10 years.
On univariate analysis, factors significantly associated with freedom from recurrence were age < 50 years at diagnosis, nonulcerated melanoma, primary lesion thickness < 1.5 mm, axillary basin site, 1 vs ≥ 3 positive SLNs, SLN metastasis diameter < 1 mm, and SLN metastasis area < 5%.
On multivariate analysis, freedom from recurrence was associated with age < 50 years at diagnosis (hazard ratio [HR] = 0.57, 95% CI = 0.39–0.84, P = .004), primary lesion thickness < 1.5 mm (HR = 0.40, 95% CI = 0.22–0.70, P = .002), axillary basin site (HR = 0.55, 95% CI = 0.31–0.96, P = .03), SLN metastasis diameter < 1 mm (HR = 0.52, 95% CI = 0.33–0.81, P = .007), and metastasis area < 5% (HR = 0.58, 95% CI = 0.38–0.88, P = .01).
In analysis by number of risk factors among age ≥ 50 years, ulceration, Breslow thickness > 3.5 mm, nonaxillary basin site, metastasis diameter ≥ 1 mm, and metastasis area ≥ 5%, nodal basin disease-free rates at 5 years were: 96% (95% CI = 88%–100%) for presence of zero risk factors, 89% (95% CI = 82%–96%) for one risk factor, 86% (95% CI = 80%–93%) for two risk factors, 80% (95% CI = 71%–89%) for three risk factors, 61% (95% CI = 48%–74%) for four risk factors, and 54% (95% CI = 36%–72%) for five or six risk factors.
The investigators concluded: “This randomized clinical trial was the largest prospective evaluation of long-term regional basin control in patients with melanoma who had nodal observation after removal of a positive SLN. SLN biopsy without CLND cleared disease in the affected nodal basin in most patients, even those with multiple risk factors for in-basin recurrence. In addition to its well-validated value in staging, SLN biopsy may also be regarded as therapeutic in some patients.”
Mark B. Faries, MD, The Angeles Clinic and Research Institute, Department of Surgery, Cedars-Sinai Medical Center, is the corresponding author for the JAMA Surgery article.
Disclosure: The study was supported by a grant from the U.S. National Institutes of Health.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.