Sentinel-node biopsy or nodal observation in melanoma

Background: We evaluated the contribution of sentinel-node biopsy to outcomes in patients with newly diagnosed melanoma. Methods: Patients with a primary cutaneous melanoma were randomly assigned to wide excision and postoperative observation of regional lymph nodes with lymphadenectomy if nodal relapse occurred, or to wide excision and sentinel-node biopsy with immediate lymphadenectomy if nodal micrometastases were detected on biopsy. Results: Among 1269 patients with an intermediate-thickness primary melanoma, the mean (+/-SE) estimated 5-year disease-free survival rate for the population was 78.3+/-1.6% in the biopsy group and 73.1+/-2.1% in the observation group (hazard ratio for death, 0.74; 95% confidence interval [CI], 0.59 to 0.93; P=0.009). Five-year melanoma-specific survival rates were similar in the two groups (87.1+/-1.3% and 86.6+/-1.6%, respectively). In the biopsy group, the presence of metastases in the sentinel node was the most important prognostic factor; the 5-year survival rate was 72.3+/-4.6% among patients with tumor-positive sentinel nodes and 90.2+/-1.3% among those with tumor-negative sentinel nodes (hazard ratio for death, 2.48; 95% CI, 1.54 to 3.98; P < 0.001). The incidence of sentinel-node micrometastases was 16.0% (122 of 764 patients), and the rate of nodal relapse in the observation group was 15.6% (78 of 500 patients). The corresponding mean number of tumor-involved nodes was 1.4 in the biopsy group and 3.3 in the observation group (P < 0.001), indicating disease progression during observation. Among patients with nodal metastases, the 5-year survival rate was higher among those who underwent immediate lymphadenectomy than among those in whom lymphadenectomy was delayed (72.3+/-4.6% vs. 52.4+/-5.9%; hazard ratio for death, 0.51; 95% CI, 0.32 to 0.81; P=0.004). Conclusions: The staging of intermediate-thickness (1.2 to 3.5 mm) primary melanomas according to the results of sentinel-node biopsy provides important prognostic information and identifies patients with nodal metastases whose survival can be prolonged by immediate lymphadenectomy. (ClinicalTrials.gov number, NCT00275496.)