Table 3.
Dose–volume statistics of VBSipCSI, which were actually used, and those of ipCSI without VBS, which were calculated for simulation but not used, in the same four AYA patients
| AYA patients VBSipCSI Mean (95% CI) | AYA patients ipCSI without VBS Mean (95% CI) | P-value | ||
|---|---|---|---|---|
| ∗CTV for CSI | Homogeneity index | 0.047 (0.024–0.070) | 0.055 (0.031–0.079) | P = 0.116 |
| Conformity index | 1.776 (0.789–2.763) | 2.058 (0.429–3.686) | P = 0.135 | |
| Total vertebral bodies | Mean dose, Gy (RBE) | 14.7 (10.5–18.9) | 26.7 (19.7–33.8) | P = 0.001 |
| Cervical region | Mean dose, Gy (RBE) | 23.1 (17.2–29.0) | 26.4 (18.0–34.7) | P = 0.012 |
| Thoracic region | Mean dose, Gy (RBE) | 16.3 (11.4–21.2) | 26.9 (20.1–33.6) | P = 0.001 |
| Lumbar region | Mean dose, Gy (RBE) | 11.3 (7.4–15.2) | 26.7 (19.4–33.9) | P = 0.002 |
| Heart | Mean dose, Gy (RBE) | 0.0 (0.0–0.0) | 0.8 (0.1–1.5) | P = 0.019 |
| V20 (%) | 0.0 (0.0–0.0) | 0.3 (−0.1–0.7) | P = 0.058 | |
| V10 (%) | 0.0 (0.0–0.0) | 2.2 (0.2–4.2) | P = 0.020 | |
| V5 (%) | 0.0 (0.0–0.0) | 5.0 (0.6–9.3) | P = 0.018 | |
| Lung | Mean dose, Gy (RBE) | 0.8 (0.3–1.4) | 1.6 (0.3–2.8) | P = 0.092 |
| V20 (%) | 0.4 (−0.3–1.0) | 2.7 (−1.0–6.4) | P = 0.053 | |
| V10 (%) | 2.8 (0.4–5.2) | 5.8 (1.3–10.3) | P = 0.072 | |
| V5 (%) | 5.7 (1.9–9.5) | 8.5 (2.9–14.1) | P = 0.156 | |
| Abdominal cavity | Mean dose, Gy (RBE) | 0.1 (0.0–0.2) | 0.5 (0.1–0.8) | P = 0.011 |
| V20 (%) | 0.1 (0.0–0.2) | 0.4 (−0.1–0.8) | P = 0.097 | |
| V10 (%) | 0.5 (0.3–0.6) | 1.4 (0.1–2.7) | P = 0.047 | |
| V5 (%) | 1.0 (0.6–1.4) | 2.6 (0.7–4.4) | P = 0.024 |
∗Whole brain and whole thecal sac, except one patient of whom CTV was only whole thecal sac. VBSipCSI = vertebral-body-sparing intensity-modulated proton craniospinal irradiation, AYA = adolescent and young adult, CI = confidence interval, CTV = clinical target volume, RBE = relative biological effectiveness.