Patterns of early recurrence after sentinel lymph node biopsy for melanoma

Background: Patterns of early recurrence after sentinel lymph node (SLN) biopsy for melanoma was determined from the Sunbelt Melanoma Trial, which includes patients with Breslow thickness ≥1.0 mm and nonpalpable regional lymph nodes. Methods: SLN were evaluated by routine histology and S-100 protein stain. Overall, there were 1,183 patients with a median follow-up of 16 months. Results: SLN were positive in 233 of 1,183 patients (20%). The recurrence rate was greater among patients with histologically positive SLN than those with negative SLN (15.5% versus 6.0%, respectively, P <0.05). Patients with positive SLN were more likely to have distant metastases (as opposed to locoregional recurrence) than those with negative SLN (67% versus 46%, respectively, P <0.05). By multivariate analysis, SLN status, Breslow thickness, Clark level, and ulceration were significant independent factors associated with early recurrence. Of patients with negative SLN, 14 of 950 (1.5%) experienced metastatic disease in lymph node basins which were staged as negative for tumor by SLN biopsy initially. Conclusions: Early regional lymph node recurrence was very uncommon after positive SLN biopsy and completion lymphadenectomy. Patients with positive SLN are more likely than those with negative SLN to develop both local/in-transit recurrence and distant metastases within a short follow-up period.