Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma

Abstract

Background: Sentinel-lymph-node biopsy is associated with increased melanoma-specific survival (i.e., survival until death from melanoma) among patients with node-positive intermediate-thickness melanomas (1.2 to 3.5 mm). The value of completion lymph-node dissection for patients with sentinel-node metastases is not clear.

Methods: In an international trial, we randomly assigned patients with sentinel-node metastases detected by means of standard pathological assessment or a multimarker molecular assay to immediate completion lymph-node dissection (dissection group) or nodal observation with ultrasonography (observation group). The primary end point was melanoma-specific survival. Secondary end points included disease-free survival and the cumulative rate of nonsentinel-node metastasis.

Results: Immediate completion lymph-node dissection was not associated with increased melanoma-specific survival among 1934 patients with data that could be evaluated in an intention-to-treat analysis or among 1755 patients in the per-protocol analysis. In the per-protocol analysis, the mean (±SE) 3-year rate of melanoma-specific survival was similar in the dissection group and the observation group (86±1.3% and 86±1.2%, respectively; P=0.42 by the log-rank test) at a median follow-up of 43 months. The rate of disease-free survival was slightly higher in the dissection group than in the observation group (68±1.7% and 63±1.7%, respectively; P=0.05 by the log-rank test) at 3 years, based on an increased rate of disease control in the regional nodes at 3 years (92±1.0% vs. 77±1.5%; P<0.001 by the log-rank test); these results must be interpreted with caution. Nonsentinel-node metastases, identified in 11.5% of the patients in the dissection group, were a strong, independent prognostic factor for recurrence (hazard ratio, 1.78; P=0.005). Lymphedema was observed in 24.1% of the patients in the dissection group and in 6.3% of those in the observation group.

Conclusions: Immediate completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not increase melanoma-specific survival among patients with melanoma and sentinel-node metastases. (Funded by the National Cancer Institute and others; MSLT-II ClinicalTrials.gov number, NCT00297895 .).

Figure 1. Trial Design, Enrollment, and Outcomes

RT-PCR denotes reverse-transcriptase polymerase chain reaction.

Figure 2. Melanoma-Specific Survival, According to Trial Group and Method of Detection of Metastasis

Panel A shows melanoma-specific survival according to trial group (completion lymph-node dissection or observation) in the per-protocol analysis. Panel B shows melanoma-specific survival according to the method of detection of sentinel-node metastasis (RT-PCR or pathological assessment). Subgroup 1 comprised patients in the dissection group with pathologically detected metastases; subgroup 2, patients in the observation group with pathologically detected metastases; subgroup 3, those in the dissection group with RT-PCR–detected metastases; and subgroup 4, those in the observation group with RT-PCR–detected metastases. P values were calculated with the use of log-rank tests.

Figure 3. Disease-free Survival, Survival without Nodal Recurrence, and Distant Metastasis–free Survival, According to Trial Group, and the Cumulative Rate of Nonsentinel-Node Metastasis

Panel A shows disease-free survival, Panel B shows survival without nodal recurrence, and Panel C shows distant metastasis–free survival according to trial group (completion lymph-node dissection or observation). Subgroup 1 comprised patients in the dissection group with pathologically detected metastases; subgroup 2, patients in the observation group with pathologically detected metastases; subgroup 3, those in the dissection group with RT-PCR–detected metastases; and subgroup 4, those in the observation group with RT-PCR–detected metastases. Panel D shows the cumulative rate of nonsentinel-node metastasis among patients in the dissection group who had positive findings on pathological assessment or nodal recurrence and among patients in the observation group who had nodal recurrence. P values were calculated with the use of log-rank tests.