Table 1.

Background characteristics of patients, n (%)

Characteristics
Sex
Male	9 (64)
Female	5 (36)
Age in yr, mean (range)	62.1 (45-75)
Tumor location
Cervical esophagus	0 (0)
Upper thoracic esophagus	1 (7)
Middle thoracic esophagus	7 (50)
Lower thoracic esophagus	6 (43)
Macroscopic type
0-IIa	13 (93)
0-IIc	1 (7)
Tumor size in mm, mean (range)	51.7 (43.8-60.7)
Resection size in mm, mean (range)	55.5 (47.5-65.0)
Transverse extension of mucosal defect
≥ 3/4 and < 7/8 circumference	11 (79)
≥ 7/8 circumference	1 (7)
The entire circumference	2 (14)
Longitudinal extension of the mucosal defect
< 50 mm	3 (21)
≥ 50 mm	11 (79)
Depth of tumor invasion
M1 or M2	12 (86)
M3	2 (14)

M1: Tumor limited to the epithelium; M2: Tumor invading the lamina propria; M3: Tumor invading the muscularis mucosa.