Sentinel lymph node biopsy for melanoma: an important risk-stratification tool

In reply: We thank Zagarella and colleagues for their comments and the opportunity to correct some misconceptions about the Multicenter Selective Lymphadenectomy Trial-1 study.1

It is unclear why they have taken exception to the reporting of disease-specific survival as this is a more robust end point than overall survival and, in this patient cohort (median age, 52 years), the two outcomes are likely equivalent.

The subgroup analysis of patients with lymph node involvement was preplanned, and the novel and robust statistical method (latent subgroup analysis) showed improved outcomes with early intervention for node-positive patients. This finding is intuitive, and Zagarella and colleagues provide no evidence as to why they consider this “unreliable”.

Sentinel lymph node biopsy (SLNB) has repeatedly been shown to be the most significant independent predictor of survival in clinically lymph node-negative patients, including by Mitra et al,2 also cited by Zagarella and colleagues. The use of ultrasound or other clinicopathological algorithms have not been reproducible and cannot be used a surrogate.3

Until a better test is developed, SLNB remains the gold standard staging test for clinically lymph node-negative patients with intermediate thickness melanoma.