Table 1. Characteristics of the included studies in this meta-analysis.

Author	Esophageal stenosis definition	Comparisons	Number	Disease stage	Treatment modalities (number)	Age (years)	Follow-up time	Study design	Quality assessment
Morgan 2008	Failure to cross at endoscopic ultrasonography.	Patients with esophageal stenosis	12	NA	Surgery: 2; dCRT: 6; palliative therapy: 4	Median: 64 (range, 50–83)	NA	Cohort	NOS: 6
		Patients without	399	NA	Surgery: 127; dCRT: 145; palliative therapy: 127	Median: 68 (range, 47–89)	NA
Clavier 2014	Non-traversable esophageal stricture by a conventional endoscope	Patients with esophageal stenosis	40	NA	dCRT: 40	Median for all patients: 65 (range, 42–81)	Median follow-up for all patients: 20.8 months	Cohort	NOS: 7
		Patients without	103	NA	dCRT: 103
Cho 2017	Endoscopic ultrasonography non-traversable	Patients with esophageal stenosis	26	Clinical stage II: 9; clinical stage III: 17	Multimodality therapy: 26	Median: 61.0	Median follow-up for all patients: 29.9 months	Cohort	NOS: 7
		Patients without	63	Clinical stage II: 39; clinical stage III: 24	Multimodality therapy: 63	Median: 62.0
Yang 2017	Significant stenosis allowing endoscopic passage with remarkable resistance or severe stenosis preventing passage of the endoscope through the tumor site	Patients with esophageal stenosis	139	T1–2 disease: 16; T3–4 disease: 123	Surgery with adjuvant therapy: 99; surgery without adjuvant therapy: 40	Mean: 59.3 (range, 41–78)	Median follow-up for all patients: 37.5 months	Cohort	NOS: 7
		Patients without	369	T1–2 disease: 154; T3–4 disease: 215	Surgery with adjuvant therapy: 236; surgery without adjuvant therapy: 133	Mean: 59.8 (range, 31–80)
Okuno 2017	Patients who experienced dysphagia or patients whose primary lesions were too narrow for an endoscopy to be performed	Patients with esophageal stenosis	61	NA	CRT: 61	NA	NA	Cohort	NOS: 6
		Patients without	70	NA	CRT: 61	NA	NA

NA, not available; dCRT, definitive chemoradiotherapy; CRT, chemoradiotherapy; NOS, the Newcastle-Ottawa Scale.