Patient characteristics and treatment parameters
| Variable | SRS and ipilimumab | SRS and nivolumab | |
|---|---|---|---|
| N = 45 | N = 35 | p | |
| Sex (F/M) | 17/28 | 14/21 | 1.0 |
| Age (years) | |||
| median | 54 | 56 | 0.2 |
| range | 23–78 | 26–80 | |
| KPS | 0.8 | ||
| median | 80 | 80 | |
| 60–70 | 13 | 9 | |
| 80–100 | 32 | 26 | |
| BRAF mutation | 0.8 | ||
| present | 15 | 13 | |
| absent | 30 | 22 | |
| undetermined | |||
| Extracranial disease | 0.7 | ||
| present | 34 | 25 | |
| absent | 11 | 10 | |
| Number of metastases | 0.4 | ||
| single | 8 | 9 | |
| multiple | 37 | 26 | |
| DS-GPA | 0.3 | ||
| 0–1 | 9 | 6 | |
| 1.5–2.5 | 22 | 16 | |
| 3–4 | 14 | 13 | |
| Type of SRS | 0.76 | ||
| Single-fraction SRS | 153 | 132 | |
| Fractionated SRS | 22 | 19 | |
| Size of metastases | 0.8 | ||
| < 2 cm | 99 | 84 | |
| 2–3 cm | 46 | 38 | |
| ≥ 3 cm | 30 | 29 | |
| Total tumor volume (cm3) | 0.1 | ||
| median | 7.4 | 9.2 | |
| range | 0.5–33.1 | 0.7–33 | |
| GTV (cm3) | 0.6 | ||
| median | 1.12 | 1.2 | |
| range | 0.05–27.9 | 0.4–31.2 | |
| PTV (cm3) | 0.3 | ||
| median | 1.71 | 1.83 | |
| range | 0.1–39.1 | 0.09–42.6 | |
| Conformity indexa | 0.5 | ||
| median | 1.43 | 1.41 | |
| range | 1.10–1.91 | 1.12–1.85 | |
SRS stereotactic radiosurgery, KPS Karnofsky Performance Status
DS-GPA Diagnosis-Specific Graded Prognostic Factors, GTV Gross Target Volume
PTV Planning Target Volume, acalculated as prescribed isodose volume/tumor volume
encompassed by the prescription isodose volume