Excluding PTV from lung volume may better predict radiation pneumonitis for intensity modulated radiation therapy in lung cancer patients

Table 3 Difference of dosimetric factors between RP2 and non-RP2 groups

Factors	Non-RP2		RP2		P Value*
Factors	Median	Range	Median	Range	P Value*
Lung-PTV method
V5 Lung-PTV (%)	48	23–76	50.5	31–78	0.046
V20 Lung-PTV (%)	18	8–26	19	15–31	0.035
MLD Lung-PTV (Gy)	10.3	6.0–15.1	11.3	7.9–15.6	0.016
Lung-PGTV method
V5 Lung-PGTV (%)	51	26–76	52.5	33–80	0.085
V20 Lung-PGTV (%)	22	11–31	24	18–34	0.046
MLD Lung-PGTV (Gy)	12.1	7.0–17.0	13.1	9.7–18.1	0.076
Total Lung Method
V5 Total Lung (%)	52	27–77	53	36–80	0.091
V20 Total Lung (%)	23	11–31	24	20–36	0.080
MLD Total Lung (Gy)	12.6	7.2–17.3	13.7	10.1–19.6	0.097

Abbreviation: RP2 radiation pneumonitis≥ grade 2, PTV planning target volume, PGTV planning gross tumor volume, V5/20 volume of lung receiving a dose ≥5/20 Gy, MLD mean lung dose
*By Mann-Whitney U test

ISSN: 1748-717X