Table 1.
Patient characteristics of the training and the validation cohort.
| Factor | Training | Validation | p Value | ||
|---|---|---|---|---|---|
| N | Rate | N | Rate | ||
| N | 250 | 108 | |||
| Histology | |||||
| Adenocarcinoma | 47 | 18.8% | 18 | 16.7% | 0.98 |
| Squamous cell carcinoma | 10 | 4.0% | 4 | 3.7% | |
| Others | 15 | 6.0% | 7 | 6.5% | |
| None | 178 | 71.2% | 79 | 73.1% | |
| Location | |||||
| Central | 39 | 15.6% | 12 | 11.1% | 0.26 |
| Peripheral | 211 | 84.4% | 96 | 88.9% | |
| Site | |||||
| Right upper lobe | 72 | 28.8% | 40 | 37.0% | 0.31 |
| Right middle lobe | 20 | 8.0% | 7 | 6.5% | |
| Right lower lobe | 57 | 22.8% | 21 | 19.4% | |
| Left upper lobe | 65 | 26.0% | 20 | 18.5% | |
| Left lower lobe | 36 | 14.4% | 20 | 18.5% | |
| C/T ratio | |||||
| ≥50% | 200 | 80.0% | 89 | 82.4% | 0.66 |
| <50% | 50 | 20.0% | 19 | 17.6% | |
| Maximum tumor diameter | |||||
| Mean (mm) | 20.5 | 20.8 | 0.85 | ||
| SD | 10.5 | 9.3 | |||
| Age | |||||
| Mean (y.o.) | 77.1 | 77.8 | 0.47 | ||
| SD | 8.9 | 8.1 | |||
| KPS | |||||
| Mean (%) | 89.0 | 88.5 | 0.52 | ||
| SD | 5.8 | 6.4 | |||
| SUV-max | |||||
| Mean | 5.9 | 5.5 | 0.59 | ||
| SD | 5.1 | 4.2 | |||
| Total radiation dose | |||||
| Mean (Gy) | 52.5 | 51.5 | 0.11 | ||
| SD | 4.6 | 7.6 | |||
| Sex | |||||
| Male | 169 | 67.6% | 76 | 70.4% | 0.60 |
| Female | 81 | 32.4% | 32 | 29.6% | |
| RT technique | |||||
| VMAT | 171 | 68.4% | 70 | 64.8% | 0.23 |
| Fixed multi-port | 75 | 30.0% | 33 | 30.6% | |
| Both | 4 | 1.6% | 5 | 4.6% | |
| Salvage treatment | |||||
| Systemic therapy | 15 | 6.0% | 9 | 8.3% | 0.45 |
| Radiotherapy | 9 | 3.6% | 3 | 2.8% | |
| Chemoradiotherapy | 3 | 1.2% | 0 | 0.0% | |
| Surgery | 3 | 1.2% | 0 | 0.0% | |
| Other treatment | 2 | 0.8% | 0 | 0.0% | |
| None | 29 | 11.6% | 11 | 10.2% | |
| Unknown | 1 | 0.4% | 3 | 2.8% | |
| No recurrence | 188 | 75.20% | 82 | 75.9% | |
C/T―consolidation/tumor; KPS―Karnofsky performance status; SUV-max―maximum standard uptake value; RT―radiotherapy; VMAT―volumetric modulated arc therapy.