The investigators decided to terminate the study early because there were no patient candidates available for registration in the center.

Endoscopic submucosal dissection (ESD) is an advanced technique that enables en bloc resection of superficial tumors in the gastrointestinal tract. ESD, however, is a time-consuming procedure that requires a high level of endoscopic skill to achieve a desirable oncologic outcome. Especially, ESD for the lesion which is located in the antrum of lesser curvature side is difficult. Because the antrum of lesser curvature side is dependent position, irrigated water and blood may prevent visual field of ESD.

Generally, whole precutting around the lesion during the ESD is performed prior to dissection. However, it is expected that partial precutting method for the lesion located in the antrum of the lesser curvature may improve the visibility of ESD because it can help us the flap of the lesion evaginated easily. Therefore, we aimed to evaluate the procedure time of ESD for the lesion located in the antrum of the lesser curvature according to the precutting methods (whole precutting vs. partial precutting).

Inclusion Criteria:

1. Over 19 years old
2. Patients with gastric adenoma or early gastric cancer

Exclusion Criteria:

1. Patients who has undergone subtotal gastrectomy
2. Patients who has undergone gastrostomy
3. Patients with local recurred gastric adenoma or early gastric cancer