Colonoscopy plays an important role in detecting colorectal neoplasms in patients with gastric neoplasms

Table 1 Baseline characteristics of included studies

Ref.	Country	Study date	Study type	Patients	Patients in the study group	Evaluation of outcomes	Conclusion	NOS
Chung et al[16], 2017	Korea	January 2009-December 2012	Retrospective case-control study	402	EGC	Colorectal neoplasm and advanced polyps	Colonoscopy plays an important role with respect to the detection of synchronous advanced colorectal neoplasm in patients with EGC	7
Imai et al[11], 2017	Japan	January 2010-December 2012	Retrospective case-control study	390	EGC	High-risk adenomas	Patients with EGC had a significant risk for colorectal cancer	6
Joo et al[12], 2010	Korea	January 2002-December 2008	Retrospective case-control study	372	GN	Adenomatous and cancerous colon polyps	Endoscopists should consider performing routine fiberoptic colonoscopy in patients undergoing endoscopic removal of GNs	7
Kim et al[13], 2022	Korea	January 2015-December 2016	Prospective case-control study	220	EGN	Colorectal adenoma	More stringent colonoscopy surveillance should be considered in elderly patients with EGN	6
Kim et al[17], 2013	Korea	September 2005-August 2010	Prospective case-control study	832	Gastric adenoma or cancer	Colorectal adenoma or cancer	Screening colonoscopy should be considered for gastric adenoma or cancer patients	8
Koh et al[20], 2022	Korea	January 2010-July 2018	Retrospective case-control study	1505	Gastric adenoma or cancer	Adenoma and cancerous colon polyps	Patients with GN are regarded as a high-risk group for colorectal cancer and are recommended for screening colonoscopy at the time of diagnosis	8
Lee et al[14], 2011	Korea	October 2008-September 2010	Prospective case-control study	214	GN	Colorectal neoplasm and high-risk colorectal neoplasm	A screening colonoscopy should be considered in patients with EGN undergoing endoscopic submucosal dissection	6
Lee et al[15], 2011	Korea	July 2005-June 2010	Retrospective case-control study	369	GC	Colorectal neoplasms	Patients with stomach cancer should be regarded as a high-risk group for colorectal neoplasms, and colonoscopy should be recommended for screening	7
Park et al[31], 2010	Korea	November 2004-October 2006	Prospective case-control study	1629	GC	Colorectal neoplasia including colorectal cancer and adenoma	There is a higher prevalence and risk of colorectal cancer in patients diagnosed with GC	9
Yoo et al[32], 2013	Korea	January 2009-December 2010	Prospective case-control study	990	GC	Colorectal neoplasm	Preoperative colonoscopy is strongly indicated in patients with GC	8

GC: Gastric cancer; EGC: Early gastric cancer; GN: Gastric neoplasm; EGN: Early gastric neoplasm; NA: Not applicable; NOS: Newcastle-Ottawa Scales.