Table 4.

Univariable and Multivariable Cox Proportional Hazard Regression Analyses of Factors Associated With PFS.

Characteristic	OR (95% CI)	P
Univariate analysis
Age (<72 vs ≥72 years)	1.391 (0.725 to 2.669)	.321
Sex (female vs male)	1.513 (0.746 to 3.066)	.251
ECOG (0-1 vs 2)	1.170 (0.576 to 2.379)	.664
Smoker (No vs others)	1.159 (0.607 to 2.214)	.655
Underlying respiratory system disease (No vs others)	1.168 (0.608 to 2.242)	.642
Tumor diameter (<22.5 vs ≥22.5 mm)	2.228 (1.154 to 4.302)	.017
Tumor location (Peripheral vs central)	1.323 (0.624 to 2.805)	.465
GTV (<8.2 vs ≥8.2 cm3)	2.074 (1.024 to 4.200)	.043
PTV (<32 vs ≥32 cm3)	2.138 (1.115 to 4.101)	.022
Fractionation (50 Gy/5 fractions vs 60 Gy/10 fractions)	3.396 (1.413 to 8.160)	.006
Pre-SBRT TLCs (<1600 vs ≥1600 cells/µL)	0.709 (0.367 to 1.370)	.306
Post-SBRT TLCs (lymphopenia vs ≥non-lymphopenia)	0.440 (0.228 to 0.851)	.015
LR (non-LR vs LR)	0.683 (0.342 to 1.361)	.278
Dynamic pattern of lymphocytes (G0 patients with LR vs others)	4.591 (1.408 to 14.969)	.011
Multivariate analysis without dynamic pattern of lymphocytes
Age (<72 vs ≥72 years)	2.194 (1.111 to 4.336)	.024
Fractionation (50 Gy/5 fractions vs 60 Gy/10 fractions)	3.567 (1.456 to 8.741)	.005
Post-SBRT TLCs (lymphopenia vs ≥non-lymphopenia)	2.406 (1.213 to 4.772)	.012
Multivariate analysis with dynamic pattern of lymphocytes
Age (<72 vs ≥72 years)	2.101 (1.086 to 4.067)	.028
Fractionation (50 Gy/5 fractions vs 60 Gy/10 fractions)	2.941 (1.204 to 7.183)	.018
Dynamic pattern of lymphocytes (G0 patients with LR vs others)	4.415 (1.315 to 14.823)	.016

Abbreviations: PFS, progression-free survival; OR, odds ratio; CI, confidence interval; ECOG, Eastern Cooperative Oncology Group; GTV, gross tumor volume; PTV, planning target volume; SBRT, stereotactic body radiation therapy; TLCs, total lymphocyte counts; LR, lymphocyte counts recovery.