Treatment of over 20 mm gastric cancer by endoscopic submucosal dissection using an insulation-tipped diathermic knife

Table 1 Characteristics and results of clinical data of patients in the over and under 20 mm groups

	Over 20 mmgroup(21-40 mm)	Under 20 mmgroup(11-20 mm)	P
Number of patients	40	72
Mean age (yr)	70.6 ± 5.7	70.1 ± 8.7	NS
Mean size of the lesion (mm)	27.6 ± 5.7	14.9 ± 3.2	< 0.001
Frequency of the cardiopulmonary underlying disease (%)	5.0	5.6	NS
Frequency of the anticoagulant therapy (%)	10	11	NS
One piece resection rate (%)	95	96	NS
Complete resection rate (%)	85	89	NS
Operation time (min)	72.3 ± 46.8	66.5 ± 59.7	NS
Complications
Rate of bleeding (%)	5	4.2	NS
Rate of perforation (%)	0	1.4	NS
Depth of invasion (mucosa:submucosa)	37:3	69:3

NS: not significant.