Baseline characteristics
| N (%) | |
| Age (years) | |
| Median (range) | 75 (64 to 91) |
| Sex | |
| Male | 18 (78) |
| Female | 5 (22) |
| ECOG Performance Status | |
| 0 | 8 (35) |
| 1 | 12 (52) |
| 2 | 3 (13) |
| Ethnicity | |
| Caucasian | 19 (83) |
| Mediterranean | 3 (13) |
| Pacific Islander | 1 (4) |
| Site of primary tumor | |
| Head and neck | 6 (26) |
| Upper limb | 5 (22) |
| Lower limb | 4 (17) |
| Trunk | 1 (4) |
| Unknown | 7 (30) |
| ICI | |
| Avelumab (PD-L1 inhibitor) | 15 (65) |
| Pembrolizumab (PD-1 inhibitor) | 5 (22) |
| Tislelizumab (PD-1 inhibitor) | 3 (13) |
| MCPyV status | |
| Positive | 7 (30) |
| Negative | 16 (70) |
| Presence of visceral disease | 17 (74) |
| Prior platinum-based chemotherapy | 10 (43) |
| Prior immunosuppression | 2 (9) |
| History of autoimmune disease | 2 (9) |
ECOG, Eastern Cooperative Oncology Group; ICI, immune checkpoint inhibitor; MCPyV, Merkel cell polyomavirus.