Table 3.
Univariate comparison of symptomatic RP positive and negative groups
| Parameter | RP (−) N = 159 Median (IQR) |
RP (+) N = 16 Median (IQR) |
Absolute difference | Percentage difference | P-value |
|---|---|---|---|---|---|
| Tumor size and dose | |||||
| Tumor diameter (cm) | 2.8 (2.0–4.2) | 3.1 (2.1–5.0) | +0.3 | 8.5 | .48 |
| GTV diameter (cm) | 2.2 (1.6–3.1) | 2.5 (1.6–4.0) | +0.3 | 12.8 | .40 |
| GTV volume (cm3) | 5.8 (2.1–15.0) | 8.5 (2.1–34.2) | +2.7 | 37.2 | .41 |
| PTV diameter (cm) | 3.9 (3.2–5.0) | 4.4 (3.3–5.4) | +0.5 | 12.0 | .35 |
| PTV volume (cm3) | 31.5 (17.5–62.0) | 44.9 (19.7–84.8) | +13.4 | 35.1 | .37 |
| Prescription BED3 | 240.0 (216.7–258.3) | 257.5 (216.7–258.3) | +17.5 | 7.0 | .50 |
| PTV-to-GTV ratio | 5.5 (3.6–9.0) | 4.9 (2.8–8.7) | −0.6 | 11.6 | .86 |
| PTV Dmax (Gy) | 62.5 (56.3–62.5) | 62.5 (62.5–68.4) | 0.0 | 0.0 | .06 |
| Total Lung | |||||
| MLD (Gy) | 3.0 (2.2–4.0) | 4.0 (3.1–5.4) | +1.0 | 27.3 | .02 |
| V2.5 Gy (%) | 22.8 (15.4–30.3) | 28.3 (21.9–36.8) | +5.5 | 21.6 | .06 |
| V5 Gy (%) | 13.6 (9.4–18.2) | 16.2 (12.7–22.4) | +2.6 | 17.2 | .09 |
| V10 Gy (%) | 8.3 (5.6–12.2) | 10.7 (8.0–16.1) | +2.5 | 25.9 | .04 |
| V13 Gy (%) | 6.3 (4.1–9.0) | 8.9 (5.9–12.7) | +2.6 | 33.6 | .03 |
| V20 Gy (%) | 3.6 (2.2–5.3) | 5.8 (3.2–8.5) | +2.2 | 47.0 | .02 |
| V30 Gy (%) | 1.8 (1.1–2.9) | 3.3 (1.7–4.4) | +1.5 | 60.0 | .02 |
| V40 Gy (%) | 1.0 (0.7–1.6) | 1.7 (1.0–2.6) | +0.7 | 49.3 | .03 |
| V50 Gy (%) | 0.5 (0.4–0.9) | 0.8 (0.6–1.4) | +0.2 | 32.6 | .03 |
| VP Gy (%) | 0.6 (0.4–0.9) | 0.7 (0.5–1.4) | +0.1 | 22.2 | .05 |
| Ipsilateral lung | |||||
| MLD (Gy) | 5.3 (3.7–7.2) | 8.0 (5.4–10.4) | +2.8 | 42.3 | <.01 |
| V2.5 Gy (%) | 31.8 (23.3–42.8) | 39.7 (35.3–50.9) | +7.9 | 22.0 | <.01 |
| V5 Gy (%) | 24.6 (18.1–34.1) | 33.8 (27.6–44.1) | +9.3 | 31.8 | <.01 |
| V10 Gy (%) | 16.6 (10.8–23.8) | 24.3 (17.0–32.3) | +7.7 | 37.5 | .01 |
| V13 Gy (%) | 12.8 (8.1–19.0) | 20.4 (13.2–26.8) | +7.5 | 45.5 | .01 |
| V20 Gy (%) | 7.3 (4.3–11.4) | 13.4 (7.5–18.1) | +6.1 | 58.5 | .01 |
| V30 Gy (%) | 3.8 (2.3–6.8) | 7.5 (3.6–10.8) | +3.7 | 65.4 | .02 |
| V40 Gy (%) | 2.4 (1.4–4.2) | 4.2 (2.2–6.7) | +1.8 | 53.8 | .02 |
| V50 Gy (%) | 1.5 (0.9–2.7) | 2.5 (1.5–4.1) | +1.1 | 53.3 | .03 |
| VP Gy(%) | 1.4 (0.9–2.6) | 2.1 (1.5–4.1) | +0.7 | 39.1 | .05 |
| Heart | |||||
| Mean dose (Gy) | 0.4 (0.1–2.1) | 1.2 (0.4–3.3) | +0.7 | 89.3 | .10 |
| Max dose (Gy) | 6.0 (0.5–17.4) | 12.5 (1.6–32.2) | +6.5 | 69.9 | .03 |
| Airway | |||||
| Mean dose (Gy) | 3.1 (1.0–6.2) | 4.9 (2.3–8.4) | +1.9 | 46.6 | .13 |
| Max dose (Gy) | 12.4 (6.3–20.4) | 17.9 (9.6–25.4) | +5.4 | 35.9 | .10 |
Abbreviations: BED3 = biologically effective dose at an alpha:beta ratio of 3 Gy; GTV = gross tumor volume; IQR = interquartile range; MLD = mean lung dose; PTV = planning target volume; RP = radiation pneumonitis.