Table 2. Univariable and multivariable Cox proportional hazards models.

Variable	Progression-free survival				Overall survival
	Univariable		Multivariable		Univariable		Multivariable
	HR (95% CI); P value		HR (95% CI); P value		HR (95% CI); P value		HR (95% CI); P value
Age	1.00 (0.98–1.02); 0.87		1.01 (0.98–1.03); 0.48		1.01 (0.98–1.03); 0.73		1.02 (0.99–1.05); 0.23
Gender	0.94 (0.56–1.56); 0.81		1.56 (0.89–2.73); 0.12		0.84 (0.48–1.48); 0.55		1.17 (0.64–2.12); 0.61
Metastases	1.92 (1.07–3.44); 0.03		1.63 (0.89–2.98); 0.11		2.11 (1.06–4.17); 0.03		1.88 (0.94–3.76); 0.08
EGFR tissue genotype	1.29 (0.90–1.85); 0.17		1.44 (0.96–2.17); 0.08		1.39 (0.93–2.09); 0.11		1.62 (1.04–2.52); 0.03
Previous EGFR TKI therapy	1.00 (0.82–1.22); 0.99		1.04 (0.84–1.29); 0.70		1.16 (0.93–1.46); 0.19		1.26 (0.99–1.61); 0.06
ctDNA	4.26 (2.55–7.10); <0.0001		4.87 (2.81–8.44); <0.0001		3.23 (1.80–5.78); <0.0001		3.49 (1.88–6.50); <0.0001

ctDNA, circulating tumor DNA; EGFR, epidermal growth factor receptor; HR, hazard ratio; 95% CI, 95% confidence interval.