Proportion of esophageal keratinized area ≥ 30% reduces accuracy of preoperative endoscopic evaluation in early esophageal squamous cell carcinoma

Table 1 Comparison of baseline clinical characteristics of early esophageal squamous cell carcinoma with and without esophageal keratosis, n (%)

Variable		Esophageal keratosis (n = 41)	Nonesophageal keratosis (n = 65)	P value
Alcohol consumption history		26 (63.41)	20 (30.77)	0.001
Smoking history		27 (65.85)	22 (33.85)	0.001
Family history		3 (7.32)	6 (9.23)	0.199
Age (year)	> 60	32 (78.05)	38 (58.46)	0.038
	≤ 60	9 (21.95)	27 (41.54)
Sex	Female	8 (19.51)	14 (21.54)	0.802
	Male	33 (80.49)	51 (78.46)

One patient had two independent lesions simultaneously in the middle and lower parts of the esophagus; one of which was early esophageal squamous cell carcinoma with keratinization and the other early nonkeratinizing squamous cell carcinoma. This patient was not included in the statistical comparison of the baseline clinical characteristics between the two groups.