Evolution of the sentinel lymph node procedure following the approval of adjuvant anti-PD-1 therapy for stage IIB and IIC melanoma: A multicenter study from RICMEL database.

[INTRODUCTION] Programmed cell death protein (PD)-1 inhibitors can be initiated for stage IIB-IIC melanomas after complete surgical resection following marketing authorization, to reduce the risk of recurrence later in the disease course. A year after this significant change to our therapeutic arsenal in France, we reflect on how this earlier initiation of immunotherapy may influence the practice of the sentinel lymph node biopsy (SLNB) and the overall staging of melanomas, particularly in an era where SLNB is increasingly considered outdated. The aim of this study is to compare the incidence of de novo IIB-IIC-III melanoma between 2021/2022 and 2023, and to examine the relationship between the stage III incidence and the number of SLN procedures to determine whether this therapeutic change has impacted melanoma staging practices.

[MATERIALS AND METHODS] We conducted a retrospective cohort study of 1158 de novo melanomas stage IIB-IIC and III diagnosed between 2021 and 2023. Data were extracted from the RICMEL database, a French, multicenter melanoma registry.

[RESULTS] The incidence of SLNB dropped significantly following the marketing authorization of adjuvant anti-PD-1 therapy, decreasing from 59.1 % in 2021/2022 to 38.1 % in 2023 (p < 0.0001). This decline was accompanied by a significant shift in the staging of IIB-IIC-III melanomas.

[CONCLUSION] Although prognostic scores or new marketing authorization could suggest performing fewer SLNBs, the reduced use of SLNB due to earlier access to immunotherapy may result in inaccurate melanoma staging, potentially affecting prognosis and treatment decisions.