Table 2.
Volume, Conformity, Intermediate dose spillage and Mean Lung Dose characteristics
| Characteristic | No Radiation Pneumonitis (n = 85) | Symptomatic Radiation Pneumonitis (n = 8) | P value |
|---|---|---|---|
| Gross Tumor Volume (GTV), cm3 | |||
| Median | 3.0 | 15.2 | < 0.001 |
| Range | 0.3–24.3 | 3.4–41.7 | |
| Integrated Tumor Volume (ITV), cm3 | |||
| Median | 6.0 | 35.4 | < 0.001 |
| Range | 0.8–39.9 | 9.0–151.8 | |
| Planning Tumor Volume (PTV), cm3 | |||
| Median | 24.9 | 77.9 | < 0.001 |
| Range | 5.7–133.3 | 32.9–370.5 | |
| Prescription dose (RxV), cm3 | |||
| Median | 26.3 | 78.1 | < 0.001 |
| Range | 6.2–135.1 | 34.3–361.9 | |
| ITV minus GTV, cm3 | |||
| Median | 3.2 | 10.2 | 0.002 |
| Range | 0–25.8 | 5.6–33.0 | |
| Conformity Index (RxV / PTV) | |||
| Median | 1.05 | 1.00 | 0.04 |
| Range | 0.89–1.44 | 0.98–1.09 | |
| Intermediate Dose Spillagea (R50V/PTV) | |||
| No deviation (%) | 36 (42.4%) | 2 (28.6%) | 0.78† |
| Minor deviation (%) | 45 (52.9%) | 5 (71.4%) | |
| Major deviation (%) | 4 (4.7%) | 0 (0.0%) | |
| Total Mean Lung Dose, Gy | |||
| Median | 3.1 | 7.0 | < 0.001‡ |
| Range | 1.0–11.0 | 4.1–9.6 | |
| Contralateral Mean Lung Dose, Gy | |||
| Median | 1.1 | 2.0 | 0.001‡ |
| Range | 0.2–3.6 | 1.6–6.4 | |
| Ipsilateral Mean Lung Dose, Gy | |||
| Median | 4.7 | 9.1 | < 0.001‡ |
| Range | 1.8–10.7 | 7.0–13.2 | |
RxV Volume receiving prescription dose, R50V Volume receiving 50% of the prescription dose. Symptomatic Radiation Pneumonitis = RTOG G3+ or CTCAE G2+ RP
aOf the entire cohort, only one patient was not able to have Intermediate Dose Spillage calculated due to a large PTV size of 370 cm3. This patient developed symptomatic radiation pneumonitis
Bolded P-values indicate statistical significance
All P-values are from Wilcoxon Rank Sum test unless otherwise noted
†P-value from Fischer exact test
‡Bonferroni Adjusted P-value