Mortality reduction from gastric cancer by endoscopic and radiographic screening

Abstract

To evaluate mortality reduction from gastric cancer by endoscopic screening, we undertook a population-based cohort study in which both radiographic and endoscopic screenings for gastric cancer have been carried out. The subjects were selected from the participants of gastric cancer screening in two cities in Japan, Tottori and Yonago, from 2007 to 2008. The subjects were defined as participants aged 40-79 years who had no gastric cancer screening in the previous year. Follow-up of mortality was continued from the date of the first screening to the date of death or up to December 31, 2013. A Cox proportional hazards model was used to estimate the relative risk (RR) of gastric cancer incidence, gastric cancer death, all cancer deaths except gastric cancer death, and all-causes death except gastric cancer death. The number of subjects selected for endoscopic screening was 9950 and that for radiographic screening was 4324. The subjects screened by endoscopy showed a 67% reduction of gastric cancer compared with the subjects screened by radiography (adjusted RR by sex, age group, and resident city = 0.327; 95% confidence interval [CI], 0.118-0.908). The adjusted RR of endoscopic screening was 0.968 (95%CI, 0.675-1.387) for all cancer deaths except gastric cancer death, and 0.929 (95%CI, 0.740-1.168) for all-causes death except gastric cancer death. This study indicates that endoscopic screening can reduce gastric cancer mortality by 67% compared with radiographic screening. This is consistent with previous studies showing that endoscopic screening reduces gastric cancer mortality.

Keywords: Cohort study; gastric cancer screening; mortality reduction; upper gastrointestinal X-ray; upper gastrointestinal endoscopy.

Figure 1

Flowchart of the selection process for the study target group to compare endoscopic and radiographic screening for gastric cancer. A total of 52 535 subjects participated in gastric cancer screening in Tottori and Yonago (Japan) from 2007 to 2008, of which 5720 participants were not within the target age for the analysis (aged more than 80 years at the time of first screening). A total of 14 394 subjects were selected as they had no gastric screening history of the previous year. Three patients who had duplication on the participant list of gastric cancer screening were excluded from 2007 to 2008 the target group of the analysis. There were 117 subjects who were identified as having a history of gastric cancer by linkage to a local cancer registry and they were also excluded from the target group. The remaining 14 274 subjects were divided into two groups according to the first screening procedure: endoscopic screening group (n = 9950), and radiographic screening group (n = 4324).

Figure 2

Cumulative hazard values of gastric cancer incidence (a) and mortality (b) in follow‐up years, estimated by the Nelson–Aalen method. Cumulative hazard values were compared between the endoscopic and radiographic screening groups.