Table 4.

Subset analyses, by tumor histology, on the impact of smoking on long-term overall, cancer-specific, and recurrence-free survival following transthoracic esophagectomy for esophageal cancers

	No. of patients	Median survival, months	Univariable HR (95% CI)	Multivariable HR (95% CI)
Adenocarcinoma
Overall survival
Current	205	37.9 (28.9–56.0)	REF	REF
Ex-smoker	428	42.0 (36.9–52.6)	0.89 (0.73–1.09), p = 0.260	0.94 (0.75–1.18), p = 0.585
Never	258	40.1 (33–56.2)	0.87 (0.70–1.09), p = 0.232	1.00 (0.78–1.29), p = 1.000
Cancer-specific survival
Current	205	55.0 (38.5–81.5)	REF	REF
Ex-smoker	428	68.5 (49.7–170.5)	0.83 (0.65–1.05), p = 0.115	0.86 (0.66–1.12), p = 0.272
Never	258	86.8 (45.1–NR)	0.81 (0.62–1.05), p = 0.110	0.86 (0.64–1.16), p = 0.315
Recurrence-free survival
Current	204	51.1 (42.7–NR)	REF	REF
Ex-smoker	424	NR (49.0–NR)	0.89 (0.69–1.15), p = 0.373	0.91 (0.69–1.22), p = 0.540
Never	258	NR (36.6–NR)	0.88 (0.66–1.18), p = 0.401	0.97 (0.70–1.33), p = 0.844
Squamous cell carcinoma
Overall survival
Current	77	33.8 (28.6–47.2)	REF	REF
Ex-smoker	102	51.6 (28.8–85.7)	0.73 (0.51–1.04), p = 0.082	0.91 (0.60–1.38), p = 0.648
Never	98	96.2 (58.3–NR)	0.48 (0.32–0.70), p < 0.001	0.77 (0.48–1.24), p = 0.278
Cancer-specific survival
Current	77	46.7 (33.8–NR)	REF	REF
Ex-smoker	102	68.2 (40.9–NR)	0.81 (0.53–1.25), p = 0.342	1.10 (0.65–1.86), p = 0.711
Never	98	153.6 (96.2–NR)	0.55 (0.35–0.88), p = 0.013	1.09 (0.60–1.98), p = 0.780
Recurrence-free survival
Current	77	97.2 (48.2–NR)	REF	REF
Ex-smoker	102	NR (37.0–NR)	0.91 (0.56–1.49), p = 0.716	1.04 (0.59–1.86), p = 0.882
Never	97	NR (NR–NR)	0.73 (0.43–1.22), p = 0.224	1.42 (0.75–2.68), p = 0.280

HR hazard ratio, CI confidence interval, NR not reached