The Effect of Nationwide Organized Cancer Screening Programs on Gastric Cancer Mortality: a Synthetic Control Study.

BACKGROUND & AIMS

Nationwide organized gastric cancer (GC) screening programs have been running for decades in South Korea and Japan. This study aimed to conduct a quasi-experimental analysis to assess the population impact of these programs on GC mortality.

METHODS

We used the flexible synthetic control method (SCM) to estimate the effect of the screening programs on age-standardized GC mortality and other upper gastrointestinal (UGI) diseases (esophageal cancer and peptic ulcer) among people aged 40 years or above. World Health Organization mortality data and country-level covariates from the World Bank and the Global Burden of Diseases study were used for the analyses. We compared post-intervention trends in outcome with the counterfactual trend of the synthetic control, and estimated average post-intervention rate ratios (RRs) with associated 95% confidence intervals (CIs). A series of sensitivity analyses were conducted.

RESULTS

The pre-intervention fits were acceptable for the analyses of South Korea and Japan's GC mortality but poor for Japan's other UGI disease mortality. The average post-intervention RRs are 0.83 (95% CI 0.71-0.96) for GC mortality and 0.72 (0.57-0.90) for other UGI disease mortality in South Korea. The RR reached 0.59 by the 15th year after the initiation of nationwide screening. For Japan, the average RRs were 0.97 (0.88-1.07) for GC mortality and 0.93 (0.68-1.28) for other UGI disease mortality. Sensitivity analysis reveals the result for Japan may potentially be biased.

CONCLUSION

South Korea's nationwide GC screening has apparent benefits while the Japanese program's effectiveness is uncertain. The experiences of South Korea and Japan could serve as a reference for other countries.

Informations de copyright

Copyright © 2023 AGA Institute. Published by Elsevier Inc. All rights reserved.