TABLE 2.

Recurrence-free survival (RFS) and overall survival (OS) analysis by clinicopathologic variables and pre- and post-operative ctDNA status.

		Univariate analysis		Multivariate analysis
Variable and RFS/OS	Num	HR (95% CI)	p	HR (95% CI)	p
Variable and RFS
Gender, male vs. female	56 vs. 21	0.534 (0.233–1.225)	0.139
Age, <=60 vs. >60	38 vs. 39	1.126 (0.579–2.190)	0.728
Smoker, ever vs. never	28 vs. 49	0.329 (0.363–1.405)	0.714
BMI, <25 vs. >=25	55 vs. 22	0.532 (0.232–1.219)	0.136
Sidedness of primary tumor, left vs. Right	31 vs. 46	1.362 (0.678–2.738)	0.386
Position, peripheral vs. central	54 vs. 23	2.014 (1.022–3.972)	0.043		0.173
Pathology, adenocarcinoma vs. SCC	40 vs. 30	0.674 (0.313–1.450)	0.313
Visceral invasion, present vs. absent	28 vs. 49	0.542 (0.279–1.053)	0.071		0.816
Stage, I/II vs. III/IV	59 vs. 18	3.491 (1.764–6.912)	0.000	2.759 (1.301–5.851)	0.008
Preoperative ctDNA status, negative vs. positive	42 vs. 35	3.858 (1.681–8.855)	0.001	3.401 (1.360–8.507)	0.009
Postoperative ctDNA status, negative vs. positive	30 vs. 41	3.108 (1.474–6.553)	0.003		0.078
Variable and OS
Gender, male vs. female	56 vs. 21	0.693 (0.277–1.738)	0.435
Age, <=60 vs. >60	38 vs. 39	1.162 (0.527–2.562)	0.709
Smoker, ever vs. never	28 vs. 49	0.865 (0.382–1.959)	0.728
BMI, <25 vs. >=25	55 vs. 22	0.524 (0.197–1.397)	0.196
Sidedness of primary tumor, left vs. Right	31 vs. 46	1.433 (0.618–3.322)	0.401
Position, peripheral vs. central	54 vs. 23	1.947 (0.873–4.339)	0.103
Pathology, adenocarcinoma vs. SCC	40 vs. 30	0.671 (0.271–1.665)	0.390
Visceral invasion, present vs. absent	28 vs. 49	0.525 (0.239–1.151)	0.108
Stage, I/II vs. III/IV	59 vs. 18	4.578 (2.068–10.138)	0.000	3.784 (1.540–9.300)	0.004
Preoperative ctDNA status, negative vs. positive	42 vs. 35	5.055 (1.731–14.756)	0.003	4.035 (1.346–12.102)	0.013
Postoperative ctDNA status, negative vs. positive	30 vs. 41	3.223 (1.348–7.707)	0.009		0.144

SCC, squamous cell carcinoma.