Table 2.

Patient factors related to grade ≥ 2 radiation pneumonitis (chi-square test)

Patient characteristics		No. of patients with grade ≤ 1 pneumonitis	No. of patients with grade ≥ 2 pneumonitis	p value
Age	≥ 68 years old	11	4	0.742
	< 68 years old	11	3
Sex	Female	19	5	0.362
	Male	3	2
Performance status	0	8	1	0.271
	1–3	14	6
ICI	Pembrolizmab	13	4	0.996
	Nivolumab	6	2
	Atezolizmab	3	1
Interval between RT and ICI	≥ 25 days	12	3	0.590
	< 25 days	10	4
History of ICI before RT	Yes	8	4	0.331
	No	14	3
Obstructive pneumonia	Yes	6	5	0.036
	No	16	2

ICI: immune checkpoint inhibitors; RT: radiotherapy.