Table 4.
Receiver operating characteristics (ROC) analysis for G2 alopecia at the end of radiotherapy.
| Dosimetric variable | AUC | p-value for AUC | Cut-off value | Sensitivity, % | Specificity, % | Incidence of acute G2 alopecia | Fisher exact test p-value | |
|---|---|---|---|---|---|---|---|---|
| Low risk, % | High risk, % | |||||||
| D0.1cc | 0.740 | 0.008 | 36.2 Gy | 87.1 | 68.7 | 50.0% | 93.7% | 0.0000 |
| Mean dose | 0.714 | 0.02 | 6.9 Gy | 87.1 | 56.2 | 55.0% | 91.3% | 0.0006 |
| V16Gy | 0.776 | 0.001 | 16.7 cc | 92.9 | 62.5 | 37.5% | 92.9% | 0.0000 |
| V20Gy | 0.792 | 0.0003 | 5.2 cc | 100.0 | 56.2 | 0% | 91.4% | 0.0000 |
| V25Gy | 0.768 | 0.002 | 5.5 cc | 85.9 | 68.7 | 52.2% | 93.5% | 0.0000 |
| V30Gy | 0.756 | 0.003 | 2.3 cc | 85.9 | 68.7 | 52.2% | 93.6% | 0.0000 |
| V35Gy | 0.736 | 0.005 | 0.7 cc | 82.4 | 68.7 | 57.7% | 93.3% | 0.0005 |
| V40Gy | 0.685 | 0.02 | 0.6 cc | 72.9 | 75.0 | 65.7% | 93.9% | 0.0004 |
| V43Gy | 0.670 | 0.04 | 0.1 cc | 70.6 | 68.7 | 69.4% | 92.3% | 0.004 |
D0.1 cc, Dose to 0.1 cc of the scalp volume; VxGy, percentage of the scalp volume receiving ≥ x Gy; AUC, area under curve at ROC analysis.
Bold text indicates statistical significance.