Table 2.
Univariate comparison of LC versus local recurrence groups
| Parameter | LC (+) N = 167 Median (IQR) |
LC (−) N = 8 Median (IQR) |
Absolute difference | Percentage difference | P-value |
|---|---|---|---|---|---|
| Tumor diameter (cm) | 2.8 (2.0–4.2) | 5.1 (3.6–5.7) | +2.3 | 58.6 | <.01 |
| GTV diameter (cm) | 2.2 (1.6–2.9) | 4.0 (2.9–4.8) | +1.8 | 44.3 | <.01 |
| GTV volume (cm3) | 5.7 (2.0–12.6) | 33.8 (13.4–57.9) | +28.1 | 83.2 | <.01 |
| PTV diameter (cm) | 3.9 (3.2–4.8) | 6.0 (4.8–6.2) | +2.1 | 35.0 | <.01 |
| PTV volume (cm3) | 31.1 (17.3–57.7) | 115.0 (57.9–121.4) | +83.9 | 72.9 | <.01 |
| Prescription BED10 | 105.6 (100.0–112.5) | 100.0 (79.0–112.5) | −5.6 | 5.6 | .21 |
| PTV Dmax (Gy) | 62.5 (60.0–62.5) | 62.5 (42.5–62.5) | 0 | 0 | .43 |
| PTV-to-GTV ratio | 5.7 (3.6–9.2) | 3.3 (2.3–4.6) | −2.4 | 72.7 | .04 |
Abbreviations: BED10 = biologically effective dose at an alpha:beta ratio of 10 Gy; Dmax = maximum point dose within the PTV; GTV = gross tumor volume; IQR = interquartile range; LC = local control; PTV = planning target volume.