This study addressed the prognostic impact of distinct patterns of metastasis and its relevance for individual target lesions (TLs) in advanced melanoma patients. Clinical and radiological data from 934 stage III and IV melanoma patients treated with anti-PD-1 monotherapy (PD1, n=421), combined immune checkpoint inhibition (COMBI, n=216), or targeted therapy (TT, n=297) at 13 skin cancer centers in Austria, Germany, and Switzerland were analyzed. Overall survival (OS), objective response rates, and individual TLs (n=2310) were compared in relation to metastatic sites. Presence of bone metastasis was a negative predictor of OS independent of treatment (PD1: p=0.0077, COMBI: p<0.0001, TT: p=0.00018). Interestingly, the strong negative impact of liver metastasis in the PD1 and TT groups was negligible in the COMBI group (HR 1.24, 95% CI 0.80-1.91, p=0.33). Brain metastasis also did not influence OS significantly in the COMBI group (p=0.53) but seriously affected OS in the PD1 group (p<0.0001) and in the TT group (p=0.015). Lymphocyte-to-monocyte-ratio was significantly lower in patients with bone (p<0.0001) or liver metastasis (p=0.0010). Comparing patients with or without liver or bone metastasis, respectively, revealed a strong impact on non-liver TLs and non-bone TLs in the PD1 group (liver: p=0.00044, bone: p=0.00048), a smaller impact in the COMBI group (p=0.314, p=0.012), and no impact in the TT group (p=0.571, p=0.989). Special sites of metastasis, especially liver, bone, and brain, deserve particular attention to select the best treatment as they distinctly influence local and systemic response.

ESDR277 - Site-Specific Tumor Response and Impact on Therapy Outcomes in Advanced Melanoma Patients

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING