Table 4.

Comparison of the mean operation time by tumor size, location, and depth

	Classification	Number	Time cost (mean ± deviation) minutes	P -value
Size	Small tumor (≤10 mm)	8	31.9 ± 5.9	0.005
	Large tumor (>10 mm)	6	46.7 ± 8.2
Location in the esophagus	Distal part (>32 cm)	8	40.6 ± 10.5	0.316
	Proximal part (≤32 cm)	6	35.0 ± 9.5
Depth of the tumor origin	Submucosal layer	8	41.3 ± 11.3	0.181
	Muscularis mucosa layer	6	34.2 ± 7.4
Total		14	38.2 ± 10.1