The Argument for Performing Sentinel Lymph Node Biopsy in Thick Primary Melanomas

Excerpt

Prospectively maintained national, population-based registries such as the Swedish Melanoma Registry (SweMR) may offer valuable real-world data to address emerging questions in the field. Specifically, the dilemma of performing sentinel lymph node biopsy (SLNB) in thick primary melanomas has become even more relevant with the advent of adjuvant immunotherapy for stages IIB and IIC melanoma. In the recent study authored by Bagge et al., the prognostic value of sentinel node biopsy for thick melanomas is convincingly confirmed.¹ This retrospective study queried the SweMR from 2007 to 2020 to determine the prognostic value of SLNB in patients with T4 melanoma. A multivariate Cox proportional hazard model for melanoma-specific survival (MSS) was performed with the readout of hazard ratio (HR) for death on the basis of Breslow thickness. Standardizing the data to the AJCC 8th edition, 10,491 patients with melanoma of Breslow thickness > 1 mm who underwent SLNB were identified and 1943 patients from this group had thick melanomas (Breslow thickness > 4 mm or pT4). In this cohort of pT4 patients, 34% had a positive SLNB. The prognosis for patients with a positive SLNB was consistently worse compared with negative SLNB status across Breslow thickness subgroups. Statistically significant differences in MSS were noted for positive patients with SLNB compared with negative patients with hazard ratio (HR) of 2.4 for pT4a and 2.0 for pT4b. Prognostic factors for MSS included SLNB status, age > 80 years, tumor ulceration, and tumor thickness. The study noted the magnitude of the HR for MSS in thick melanomas was similar to that of intermediate thickness melanomas, with a reduction in absolute MSS of 23% for positive SLNB versus negative SLNB status (92% versus 69%, respectively). …