Table 1.
Patient characteristics.
| Characteristics | All | Chordoma | Non-Chordoma |
|---|---|---|---|
| Number | 53 | 32 | 21 |
| Age, years, median (range) | 67 (14–84) | 67 (27–84) | 54 (14–83) |
| Sex, number (%) | |||
| Male | 32 (60.4%) | 24 (75%) | 8 (38.1%) |
| Female | 21 (39.6%) | 8 (25%) | 13 (61.9%) |
| Performance status | |||
| 0–1 | 47 (88.7%) | 30 (93.7%) | 17 (81.0%) |
| 2–3 | 6 (11.3%) | 2 (6.3%) | 4 (19.0%) |
| Histology, number (%) | |||
| Chordoma | 32 (60.4%) | 32 (100%) | None |
| Chondrosarcoma | 9 (17.0%) | None | 9 (42.9%) |
| Osteosarcoma | 8 (15.1%) | None | 8 (38.1%) |
| Undifferentiated pleomorphic sarcoma | 3 (5.6%) | None | 3 (14.3%) |
| Sclerosing epithelioid fibrosarcoma | 1 (1.9%) | None | 1 (4.7%) |
| Tumor site, number (%) | |||
| Pelvis | 49 (92.5%) | 30 (93.7%) | 19 (90.6%) |
| Shoulder | 1 (1.9%) | None | 1 (4.7%) |
| Spine | 3 (5.6%) | 2 (6.3%) | 1 (4.7%) |
| Prior treatment of C-ion RT | |||
| Chemotherapy | 6 (11.3%) | None | 6 (28.6%) |
| Surgery | 7 (13.2%) | 5 (15.6%) | 2 (9.5%) |
| Treatment naïve | 40 (75.5%) | 27 (84.4%) | 13 (61.9%) |
| Tumor size, mm, median (range) | 95 (15–175) | 87.5 (15–175) | 100 (16–160) |
| Minimum distance of tumor from GI, mm, median | 3.4 (0.1–96.0) | 2.3 (0.1–67.5) | 4.0 (0.1–96.0) |
| GTV volume, cm3, median (range) | 215.6 (1.6–2074.3) | 205.7 (1.6–2074.3) | 225.4 (2.2–1551.2) |
| Dose of C-ion RT, Gy (RBE) | |||
| 64.0 | 3 (5.6%) | 2 (6.3%) | 1 (4.7%) |
| 67.2 | 30 (56.6%) | 30 (93.7%) | None |
| 70.4 | 20 (37.8%) | None | 20 (95.3) |
| GTV D98, Gy (RBE), median (range) | 66.15 (43.77–70.60) | 64.24 (43.77–66.80) | 68.94 (62.77–70.60) |
| GTV D95, Gy (RBE), median (range) | 66.73 (58.36–70.70) | 66.48 (58.36–64.27) | 69.36 (63.54–70.70) |
| GTV V64, %, median (range) | 99.5 (47.1–100) | 98.3 (47.1–100) | 100 (53.7–100) |
| GTV V60, %, median (range) | 99.9 (82.4–100) | 99.7 (82.4–100) | 100 (98.7–100) |
| GTV V<64, cm3, median (range) | 0.9 (0–144.0) | 2.5 (0–144.0) | 0 (0–62.9) |
| GTV V<60, cm3, median (range) | 0.1 (0–32.3) | 0.6 (0–32.3) | 0 (0–19.4) |
Abbreviations: C-ion RT, carbon ion radiotherapy; D95 and D98, the minimum dose that covered 95% and 98% of the target volume; GTV, gross tumor volume; RBE, relative biological effectiveness; V60 and V64, percentage of the GTV volume that received at least 60 and 64 Gy (RBE); V<60 and V<65, the target volume that received less than 60 and 65 Gy (RBE).