Table 3.
Results of ROC analysis for threshold values of BMI, PTV, CCD, lung volume at FB above which all patients achieved the relative benefit of 20% or 50% in analyzed dose metrics; threshold values for which p value was <0.05 are shown in bold.
| Parameter | Threshold values for relative benefit ≥20% of improvement of dose metric |
Threshold values for relative benefit ≥50% of improvement of dose metric |
||||
|---|---|---|---|---|---|---|
| Δ MHD | Δ V20Heart | ΔLADmax | Δ MHD | Δ V20Heart | ΔLADmax | |
| BMI (kg/m2) Threshold value |
22.3 | 22.3 | 24.8 | 27.6 | 22.3 | 26.0 |
| AUC (95% CI) | 0.88 (0.75–1.0) | 0.80 (0.66–0.94) | 0.73 (0.50–0.96) | 0.76 (0.58–0.93) | 0.80 (0.66–0.94) | 0.63 (0.43–0.83) |
| CCD (cm) Threshold value |
2.9 | 2.9 | 3.8 | 5.7 | 2.9 | 3.0 |
| AUC (95% CI) | 0.99 (0.96–1.0) | 0.95(0.87–0.91) | 0.61 (0.26–0.97) | 0.76 (0.57–0.94) | 0.95 (0.87–1.0) | 0.45 (0.22–0.67) |
| PTV (cm3) Threshold value |
577.7 | 445.6 | – | 703.4 | 445.64 | – |
| AUC (95% CI) | 0.81 (0.63–0.99) | 0.90 (0.79–1.00) | 0.85 (0.71–0.98) | 0.90 (0.79–1.00) | ||
| FB lung volume (cm3) Threshold value |
2485.7 | 2589.6 | 2377.2 | 2909.6 | 2589.6 | 2804.8 |
| AUC (95% CI) | 0.58 (0.24–0.91) | 0.65 (0.48–0.82) | 0.54 (0.31–0.78) | 0.74 (0.55–0.93) | 0.65 (0.48–0.82) | 0.56 (0.35–0.76) |
MHD – mean heart dose; V20Heart – volume of heart receiving 20 Gy; LADmax – maximum dose for LAD; FB – free breathing; LAD – left anterior descending artery; AUC – area under the curve; CI – confidence interval.