Table 3. Treatment characteristics.

Variable	Total, n=77 (%)	PLLs, n=49 (%)	MLLs, n=28 (%)	P value* (level of significance)
Interval between the first diagnosis and the start of SABR (in days)
Median	48.0	48.0	52.0
Range	14–170	14–170	20–141
Mean	57.2	57.9	56.0	0.79
Interval dichotomized
≤48 days	39 [51]	26 [54]	13 [47]
>48 days	38 [49]	23 [46]	15 [53]	0.57
SABR duration (in days)
Median	9.0	9.0	7.0
Range	5–23	5–23	5–19
Mean	9.6	10.0	8.9	0.12
SABR duration dichotomized
<9 days	37 [48]	23 [46]	14 [50]
≥9 days	40 [52]	26 [54]	14 [50]	0.79
No. of fractions
Median	5.0	5.0	5.0
Range	3–10	3–10	3–8
Mean	5	5.4	4.3	0.03
No. of fractions dichotomized
<5 fractions	35 [45]	22 [45]	13 [47]
≥5 fractions	42 [55]	27 [55]	15 [53]	0.89
Dose per fraction in Gy
Median	12	12	12
Range	3.6–18	3.6–18	5–12.5
Mean	10.2	10.4	9.9	0.86
Dose per fraction dichotomized
≥12 Gy	46 [60]	30 [61]	16 [57]
<12 Gy	31 [40]	19 [39]	12 [43]	0.72
Total dose in Gy
Median	48	48	36
Range	25–60	30–60	25–60
Mean	47.9	52	40.5	0.001
Total dose dichotomized
≤48 Gy	49 [64]	26 [53]	23 [82]
>48 Gy	28 [36]	23 [47]	5 [18]	0.01
Prescription isodose line
80–95%	60 [78]	48 [98]	12 [43]
60–65%	17 [22]	1 [2]	16 [57]	0.0001
BED10 (peripheral)
Median	105	105	79
Range	37–151	48–151	37–132
Mean	97.2	105.8	82	0.0001
BED10 dichotomized
≥105 Gy	48 [62]	41 [84]	7 [25]
<105 Gy	29 [38]	8 [16]	21 [75]	0.0001
Treatment planning technique
3D conformal	50 [65]	33 [67]	17 [60]
IMRT	27 [35]	16 [33]	11 [40]	0.56
PTV volume in mL
Median	27	29	20
Range	4–147	5–147	4–98
Mean	33.8	37	28	0.12

*, pearson chi-square test for categorical and Mann-Whitney U test for continuous variables. PLLs, primary lung lesions; MLLs, metastatic lung lesions; SABR, stereotactic ablative radiotherapy; BED₁₀, biologic effective dose at α/β=10 Gy; 3D, three dimensional; IMRT, intensity-modulated radiation therapy; PTV, planning target volume.