Radiation pneumonitis in patients with non-small-cell lung cancer receiving chemoradiotherapy and an immune checkpoint inhibitor: a retrospective study

Table 4 Dosimetric factors predicting radiation pneumonitis ≥ grade 2 for patients treated with concurrent chemoradiotherapy using ICI

Variable	ICI (n = 51)		Non-ICI (n = 55)		p for interaction^†
Variable	HR (95% CI)	p	HR (95% CI)	p	p for interaction^†
Total dose, > 60 Gy	1.098 (0.507–2.377)	0.813	1.124 (0.480–2.634)	0.787	0.967
PTV volume, ≥ 280 cm³	1.001 (0.456–2.198)	0.997	1.968 (0.819–4.729)	0.130	0.260
MLD, ≥ 16 Gy	5.030 (1.886–13.416)	0.001	1.485 (0.601–3.671)	0.392	0.074
V5, ≥ 28%	3.212 (0.773–13.345)	0.108	1.741 (0.438–6.925)	0.431	0.546
V10, ≥ 23%	1.921 (0.652–5.662)	0.237	1.907 (0.561–6.488)	0.301	0.993
V20, ≥ 19%	2.177 (0.739–6.411)	0.158	3.231 (1.071–9.748)	0.037	0.615
V30, ≥ 18%	2.533 (1.155–5.557)	0.020	2.054 (0.882–4.783)	0.095	0.721
V40, ≥ 14%	2.754 (1.249–6.070)	0.001	1.964 (0.851–4.533)	0.114	0.566

ICI Immune checkpoint inhibitor, HR Hazard ratio, CI Confidence interval, PTV Planning target volume, MLD Mean lung dose, VD (V5, V10, V20, V30, V40) The percentage of lung volume receiving more than a threshold radiation dose (5, 10, 20, 30, 40 Gy)
^†Interaction effect; the effect of each variable is significantly different between ICI and non-ICI group

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