Who participates in the gastric cancer screening and on-time rescreening in the National Cancer Screening Program? A population-based study in Korea.

Gastric cancer (GC) screening is a major challenge in countries where the disease is highly prevalent. This study was conducted to identify the factors associated with participation in GC screening and on-time rescreening among the average-risk population in Korea. The study population was derived from the National Cancer Screening Program database. The population for this study was 22 913 618 individuals aged ≥40 years who had been invited to participate in a GC screening program from 2005 to 2006. We determined whether these individuals had attended the GC screening program and which method - an upper gastrointestinal series (UGIS) or endoscopy-they underwent. We followed the participants to determine whether they had a second GC screening after 2 years. The overall participation rate in the GC screening was 20.5%. More people underwent UGIS than endoscopy. Individuals who had been screened by endoscopy rather than UGIS were more likely to be younger, male, or those who were National Health Insurance (NHI) beneficiaries with a higher premium rate. Of those who underwent baseline screening, 59.4% participated in a rescreening program 2 years later. NHI beneficiaries with a higher premium rate were significantly more likely to be rescreened than medical aid recipients. The results from this study showed that the UGIS were more commonly used in organized GC screenings in Korea, and those who underwent UGIS were more likely to return for subsequent screening compared to those who underwent an endoscopy.