Regression of primary melanoma without surgery in patients treated with anti-programmed cell death-1 inhibitor therapy: A case series

Summary: Abstract Body: The advent of immune checkpoint blockade has significantly improved survival outcomes and the prognosis of advanced melanoma. In the adjuvant setting, immune checkpoint inhibitors (ICIs) have improved recurrence-free and distant metastasis-free survival [1], and neoadjuvant systemic therapy (NAST) with ICIs has emerged as a promising option for patients with palpable stage III melanoma, with several studies demonstrating promising outcomes compared to surgery alone [2]. In this case series we report five cases of locally advanced or metastatic cutaneous melanoma that were treated with ICI monotherapy and demonstrated a full or near-complete resolution of their primary tumor, obviating the need for surgery. Pathologic evaluation of primary lesions demonstrated absence of any tumor in the four patients in which it was obtained. Our experience suggests that in select cases of simultaneous primary and metastatic melanoma, surgical excision of primary tumors may not be necessary, and ICI treatment alone may be sufficient to achieve complete regression of the primary lesion. References: 1. Johnson DB, Nebhan CA, Moslehi JJ, Balko JM. Immune-checkpoint inhibitors: long-term implications of toxicity. Nature Reviews Clinical Oncology 2022; 19 (4):254-267. 2. Amaria RN, Reddy SM, Tawbi HA, Davies MA, Ross MI, Glitza IC, et al. Neoadjuvant immune checkpoint blockade in high-risk resectable melanoma. Nature Medicine 2018; 24 (11):1649-1654. Elizabeth F. Sher¹, Michelle Juarez¹, Maya Dimitrova², Ian W. Tattersall^{1, 2} 1. Ronald O. Perelman Department of Dermatology, New York University Grossman School of Medicine, New York, NY, United States. 2. Perlmutter Cancer Center, NYU Langone Health, New York, NY, United States. Clinical Research: Epidemiology and Observational Research