LAUSR

Simple Summary Nodular melanoma is associated with a higher locoregional recurrence rate and worse overall survival outcomes. Whether this histologic subtype affects the efficacy of immunotherapy or targeted therapy is unclear. The aim of our multi-center nationwide study is to identify the efficacy of immunotherapy and BRAF/MEKi therapy in metastatic nodular melanoma compared with the efficacy in metastatic superficial spreading melanoma. Our study results demonstrate no difference between the effectiveness of immunotherapy and BRAF/MEKi in metastatic nodular versus superficial melanoma patients. A shorter distant metastasis-free survival and reduced overall survival (measured as the time between primary melanoma up to death or last follow-up) was observed in the nodular melanoma patient group, suggesting worse overal survival of nodular melanoma is mainly driven by propensity of metastatic outgrowth of nodular melanoma after primary diagnosis. Abstract Nodular melanoma (NM) is associated with a higher locoregional and distant recurrence rate compared with superficial spreading melanoma (SSM); it is unknown whether the efficacy of systemic therapy is limited. Here, we compare the efficacy of immunotherapy and BRAF/MEK inhibitors (BRAF/MEKi) in advanced NM to SSM. Patients with advanced stage IIIc and stage IV NM and SSM treated with anti-CTLA-4 and/or anti-PD-1, or BRAF/MEKi in the first line, were included from the prospective Dutch Melanoma Treatment Registry. The primary objectives were distant metastasis-free survival (DMFS) and overall survival (OS). In total, 1086 NM and 2246 SSM patients were included. DMFS was significantly shorter for advanced NM patients at 1.9 years (CI 95% 0.7–4.2) compared with SSM patients at 3.1 years (CI 95% 1.3–6.2) (p < 0.01). Multivariate survival analysis for immunotherapy and BRAF/MEKi demonstrated a hazard ratio for immunotherapy of 1.0 (CI 95% 0.85–1.17) and BRAF/MEKi of 0.95 (CI 95% 0.81–1.11). A shorter DMFS for NM patients developing advanced disease compared with SSM patients was observed, while no difference was observed in the efficacy of systemic immunotherapy or BRAF/MEKi between NM and SSM patients. Our results suggests that the worse overall survival of NM is mainly driven by propensity of metastatic outgrowth of NM after primary diagnosis.