Table 2 Univariate and multivariate analyses of factors associated with grade ≥ 2 radiation pneumonitis

Age (years)

< 62

18/51

–

NE

≥62

17/57

Sex

Male

24/80

–

NE

Female

11/28

ECOG-PS ^a

0

24/64

–

NE

1–2

11/43

Smoking history (Brinkmann Index)^a

< 760

17/49

–

NE

≥760

16/55

Lobe

Lower lobe

15/27

3.75

0.004

Upper/Middle lobe

20/81

(1.39–10.5)

Laterality

Right

21/62

–

Left

14/46

Surgery

Lobectomy

26/86

–

NE

Bilobectomy

7/14

Pneumonectomy

2/8

FEV1 (L)^a

< 2.5

13/48

–

NE

≥2.5

20/53

Tumor size (mm)

< 44

22/54

–

NE

≥44

13/54

GTV volume (cc)

< 66

20/53

–

NE

≥66

15/55

Number of lymph

< 2

10/44

–

NE

Nodes

≥2

25/64

Resected lung

< 730

16/53

–

NE

volume (cc)

≥730

19/55

Residual lung

< 2500

22/53

–

NE

volume (cc)

≥2500

13/55

V5 (%)

< 32

13/55

–

NE

≥32

22/53

V20 (%)

< 21

11/55

3.27

0.349

≥21

24/53

(1.31–8.62)

MLD (Gy)

< 10

9/51

3.86

0.026

≥10

26/57

(1.50–10.8)