Table 5. Follow-up results of the two groups.

	Ex-adenoma group (n = 202)	De novo group (n = 1,086)	P value
Follow-up duration, median (IQR)	45.1 (24.3–60.9)	45.4 (24.3–61.0)	0.913
Synchronous gastric neoplasiaa	44 (21.8)	133 (12.2)	< 0.001
Synchronous gastric adenoma	30 (14.9)	85 (7.8)	0.001
Synchronous gastric carcinoma	14 (6.9)	48 (4.4)	0.126

Values are presented as median (interquartile range) or n (%)

IQR, interquartile range

^aSynchronous gastric neoplasia was defined as a gastric adenoma or cancer developed in areas other than the site of primary gastric cancer within 1 year of endoscopic submucosal dissection