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World J Gastrointest Endosc. Feb 16, 2017; 9(2): 55-60
Published online Feb 16, 2017. doi: 10.4253/wjge.v9.i2.55
Overdiagnosis of gastric cancer by endoscopic screening
Chisato Hamashima
Chisato Hamashima, Division of Cancer Screening Assessment and Management, Center for Public Health Science, National Cancer Center, Tokyo 104-0045, Japan
Author contributions: Hamashima C designed and performed the recently published research studies cited in this minireview.
Supported by Grant-in-Aid for Scientific Research, Japan by the Japanese Society for the Promotion of Science, Tokyo, Japan, No. 26460620.
Conflict-of-interest statement: The author has no conflicts of interest to report.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Chisato Hamashima, Division of Cancer Screening Assessment and Management, Center for Public Health Science, National Cancer Center, 5-1-1 Tsukiji Chuo-ku, Tokyo 104-0045, Japan. chamashi@ncc.go.jp
Telephone: +81-3-35475305 Fax: +81-3-35478587
Received: August 19, 2016
Peer-review started: August 21, 2016
First decision: September 28, 2016
Revised: November 22, 2016
Accepted: December 7, 2016
Article in press: December 9, 2016
Published online: February 16, 2017
Processing time: 179 Days and 1.5 Hours
Abstract

Gastric cancer screening using endoscopy has recently spread in Eastern Asian countries showing increasing evidence of its effectiveness. However, despite the benefits of endoscopic screening for gastric cancer, its major harms include infection, complications, false-negative results, false-positive results, and overdiagnosis. The most serious harm of endoscopic screening is overdiagnosis and this can occur in any cancer screening programs. Overdiagnosis is defined as the detection of cancers that would never have been found if there is no cancer screening. Overdiagnosis has been estimated from randomized controlled trials, observational studies, and modeling. It can be calculated on the basis of a comparison of the incidence of cancer between screened and unscreened individuals after the follow-up. Although the estimation method for overdiagnosis has not yet been standardized, estimation of overdiagnosis is needed in endoscopic screening for gastric cancer. To minimize overdiagnosis, the target age group and screening interval should be appropriately defined. Moreover, the balance of benefits and harms must be carefully considered to effectively introduce endoscopic screening in communities. Further research regarding overdiagnosis is warranted when evaluating the effectiveness of endoscopic screening.

Keywords: Gastric cancer; Cancer screening; Upper gastrointestinal endoscopy; Overdiagnosis; Harm

Core tip: Overdiagnosis is the most serious harm of cancer screening and this can occur in any cancer screening programs. It is defined as the detection of cancers that would never have been found if there is no screening. Despite the lack of standardization of the estimation method for overdiagnosis, its estimation is necessary in endoscopic screening for gastric cancer. To minimize overdiagnosis, the target age group and screening interval should be appropriately defined. Consideration of the balance of benefits and harms of endoscopic screening is imperative for its effective introduction in communities.