TABLE 3.

Univariate analysis of risk factors for symptomatic pneumonitis

Factors	Univariate analysis
	OR (95% CI)	p value
Sex
Male	0.75 (0.29–1.92)	0.547
Female
Age
<65	1.96 (0.80–4.80)	0.142
≥65
Histologic type		0.861
Adeno (ref.)
Squamous	1.06 (0.41–2.77)	0.901
Small cell	0.81 (0.30–2.19)	0.682
Disease stage
III	0.68 (0.22–2.14)	0.509
IV
ECOG PS
0	1.54 (0.53–4.48)	0.423
1
Smoking history
<40	3.18 (1.22–8.30)	0.018
≥40
Pulmonary emphysema
Yes	4.99 (1.66–14.98)	0.004
No
Interstitial pneumonia/fibrosis
Yes	2.8 (0.52–15.19)	0.233
No
Treatment line of PD‐(L)1 inhibitor
1	0.52 (0.22–1.21)	0.128
≥2
PD‐(L)1 inhibitor type
PD‐1 inhibitor	1.29 (0.36–4.54)	0.694
PD‐L1 inhibitor
Cycles of PD‐(L)1 inhibitor before TRT (%)
<4	0.85 (0.34–2.11)	0.724
≥4
BED10 (Gy)
<62.45	0.61 (0.27–1.37)	0.228
≥62.45
Time from the initiation of PD‐(L)1 inhibitor treatment to TRT (months)
<4.8	0.49 (0.22–1.13)	0.095
≥4.8
GTV (cm3)
<58	1.84 (0.81–4.22)	0.148
≥58
PTV (cm3)
<223	2.42 (1.04–5.59)	0.039
≥223
PTV/LV
<0.08	2.65 (1.14–6.15)	0.024
≥0.08
Total lung V5 (%)
<32.3	3.2 (1.36–7.53)	0.008
≥32.3
Total lung V20 (%)
<16.7	3.57 (1.51–8.45)	0.004
≥16.7
MLD (Gy)
<9.1	2.48 (1.06–5.77)	0.036
≥9.1

Abbreviations: BED10, biologically effective doses; CIs, confidence intervals; ECOG PS, Eastern Cooperative Oncology Group performance status; GTV, gross tumor volume; LV, total lungs volume; MLD, median lung dose; OR, Odds ratio; PD‐(L)1, programmed death 1/programmed death ligand 1; PTV, planning target volume; ref, reference; TRT, thoracic radiotherapy; Vx, percentage of the total lung volume receiving no less than x Gy of radiation.