Parameter No. of patients 2-year overall-survival rate (%) p-value Surgery :SR Yes No 7 11 71.4 45.5 0.6650 Immunotherapy:IT Yes No 9 9 55.6 56.6 0.2838 Radiotherapy:RT Yes No 16 2 62.5 0 0.0001 Chemotherapy:CH Yes No 13 5 61.5 40.0 0.0969 SR+IT Both Others 3 15 66.7 53.3 0.6315 SR+RT Both Others 7 11 71.4 45.5 0.6398 SR+CH Both Others 5 13 80.0 46.2 0.4134 IT+RT Both Others 8 10 62.5 50.0 0.5893 IT+CH Both Others 4 14 75.0 50.0 0.7952 RT+CH Both Others 12 6 66.7 33.3 0.0275

Table 1: Treatment analysis of various prognostic factors for 2-year overall-survival rate in patients with scalp angiosarcoma. Significance between survival curves of populations was evaluated using log-rank testing and shown as p-value. SR: Surgery, IT: Immunotherapy, RT: Radiotherapy, CH: Chemotherapy.