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 [ClinicalTrials.gov].).

Background Sentinel-node biopsy, a minimally invasive procedure for regional melanoma staging, was evaluated in a phase 3 trial. Methods We evaluated outcomes in 2001 patients with primary cutaneous melanomas 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). Results No significant treatment-related difference in the 10-year melanoma-specific survival rate was seen in the overall study population (20.8% with and 79.2% without nodal metastases). Mean (±SE) 10-year disease-free survival rates were significantly improved in the biopsy group, as compared with the observation group, among patients with intermediate-thickness melanomas, defined as 1.20 to 3.50 mm (71.3±1.8% vs. 64.7±2.3%; hazard ratio for recurrence or metastasis, 0.76; P = 0.01), and those with thick melanomas, defined as >3.50 mm (50.7±4.0% vs. 40.5±4.7%; hazard ratio, 0.70; P = 0.03). Among patients with intermediate-thickness melanomas, the 10-year melanoma-specific survival rate was 62.1±4.8% among those with metastasis versus 85.1±1.5% for those without metastasis (hazard ratio for death from melanoma, 3.09; P<0.001); among patients with thick melanomas, the respective rates were 48.0±7.0% and 64.6±4.9% (hazard ratio, 1.75; P = 0.03). Biopsy-based management improved the 10-year rate of distant disease–free survival (hazard ratio for distant metastasis, 0.62; P = 0.02) and the 10-year rate of melanoma-specific survival (hazard ratio for death from melanoma, 0.56; P = 0.006) for patients with intermediate-thickness melanomas and nodal metastases. Accelerated-failure-time latent-subgroup analysis was performed to account for the fact that nodal status was initially known only in the biopsy group, and a significant treatment benefit persisted. Conclusions 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. (Funded by the National Cancer Institute, National Institutes of Health, and the Australia and New Zealand Melanoma Trials Group; ClinicalTrials.gov number, NCT00275496.)

Lymphatic mapping and sentinel lymphadenectomy can be successfully learned and applied in a standardized fashion with high accuracy by centers worldwide. Successful SN identification rates of 97% can be achieved, and the incidence of nodal metastases approaches that of the organizing center. A multidisciplinary approach (surgery, nuclear medicine, and pathology) and a learning phase of > or =30 consecutive cases per center are sufficient for mastery of LM/SL in cutaneous melanoma. Lymphatic mapping performed using blue dye plus radiocolloid is superior to LM using blue dye alone.

ObjectiveA prospective multi-institutional randomized surgical trial involving 740 stage and 11 melanoma patients was conducted by the Intergroup Melanoma Surgical Program to determine whether elective (immediate) lymph node dissection (ELND) for intermediate-thickness melanoma (1-4 mm) improves survival rates compared with clinical observation of the lymph nodes. A second objective was to define subgroups of melanoma patients who would have a higher survival with ELND. MethodsThe eligible patients were stratified according to tumor thickness, anatomic site, and ulceration, and then were prerandomized to either ELND or nodal observation. Femoral, axillary, or modified neck dissections were performed using standardized surgical guidelines. ResultsThe median follow-up was 7.4 years. A multifactorial (Cox regression) analysis showed that the following factors independently influenced survival: tumor ulceration, trunk site, tumor thickness, and patient age. Surgical treatment results were first compared based on randomized intent. Overall 5-year survival was not significantly different for patients who received ELND or nodal observation. However, the 552 patients 60 years of age or younger (75% of total group) with ELND had a significantly better 5-year survival. Among these patients, 5-year survival was better with ELND versus nodal observation for the 335 patients with tumors 1 to 2 mm thick, the 403 patients without tumor ulceration, and the 284 patients with tumors 1 to 2 mm thick and no ulceration. In contrast, patients older than 60 years of age who had ELND actually had a lower survival trend than those who had nodal observation. When survival rates were compared based on treatment actually received (i.e., including crossover patients), the patients with significantly improved 5-year survival rates after ELND included those with tumors 1 to 2 mm thick, those without tumor ulceration, and those 60 years of age or younger with tumors 1 to 2 mm thick or without ulceration. 255

These long-term survival rates from patients treated at 77 institutions demonstrate that ulceration and tumor thickness are dominant predictive factors that should be used in the staging of stages I and II melanomas, and confer a survival advantage for these subgroups of prospectively defined melanoma patients.