Adjuvant PD-1 Checkpoint Inhibition in Early Cutaneous Melanoma: Immunological Mode of Action and the Role of Ultraviolet Radiation

• Published in: Cancers Vol. 16; no. 8; p. 1461
• Main Authors: Brandlmaier, Matthias, Hoellwerth, Magdalena, Koelblinger, Peter, Lang, Roland, Harrer, Andrea
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 11.04.2024
• Subjects: Adjuvant therapy; Antibodies; Apoptosis; Cancer therapies; Cytotoxicity; Disease prevention; Immune checkpoint inhibitors; Immunogenicity; Immunosuppression; Immunosurveillance; Immunotherapy; Lymphocytes T; Medical prognosis; Melanoma; Metastasis; PD-1 protein; Risk factors; Skin cancer; Toxicity; Tumors; Ultraviolet radiation; ultraviolet radiation; UVR exposure; lymph nodes; PD-1 checkpoint inhibition; melanomagenesis; skin; immune surveillance
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers16081461

Melanoma ranks as the fifth most common solid cancer in adults worldwide and is responsible for a significant proportion of skin-tumor-related deaths. The advent of immune checkpoint inhibition with anti-programmed death protein-1 (PD-1) antibodies has revolutionized the adjuvant treatment of high-risk, completely resected stage III/IV melanoma. However, not all patients benefit equally. Current strategies for improving outcomes involve adjuvant treatment in earlier disease stages (IIB/C) as well as perioperative treatment approaches. Interfering with T-cell exhaustion to counteract cancer immune evasion and the immunogenic nature of melanoma is key for anti-PD-1 effectiveness. Yet, the biological rationale for the efficacy of adjuvant treatment in clinically tumor-free patients remains to be fully elucidated. High-dose intermittent sun exposure (sunburn) is a well-known primary risk factor for melanomagenesis. Also, ultraviolet radiation (UVR)-induced immunosuppression may impair anti-cancer immune surveillance. In this review, we summarize the current knowledge about adjuvant anti-PD-1 blockade, including a characterization of the main cell types most likely responsible for its efficacy. In conclusion, we propose that local and systemic immunosuppression, to some extent UVR-mediated, can be restored by adjuvant anti-PD-1 therapy, consequently boosting anti-melanoma immune surveillance and the elimination of residual melanoma cell clones.