Malignant melanomas (MMs) originate from melanocytes in the basal layer of the epidermis, and they are characterized by high malignancy, early metastasis, poor prognosis, and high mortality. Depending on their location, MMs can be classified as cutaneous, uveal or mucosal. Previous studies suggest that average morbidity rates are 16.2 per 100 000 in the United States and 0.383 per 100 000 in Japan. 1 However, MMs incidence increased continuously worldwide. 2,3 MMs were the fifth most common cancer in men and the sixth most common cancer in women in 2018. According to the American Association of Cancer (AJCC) TNM staging system, the 5-year overall survival (5-y OS) rates are approximately 98.2% in patients at stages I/II, 61.7% at stage III, and 15.2% at stage IV. 4 Although stage I MMs are typically associated with good prognoses after surgical treatment only, achieving negative margins in all patients was difficult. Currently available treatment options for patients with MM include radiotherapy (RT), chemotherapy, targeted therapy, and immunotherapy. Adjuvant therapies were