Initial results from a multi-center population-based cluster randomized trial of esophageal and gastric cancer screening in China

Background: We initiated the first multi-center cluster randomized trial of endoscopic screening for esophageal cancer and gastric cancer in China. The objective of the study was to report the baseline screening findings in this trial. Methods: We recruited a total of 345 eligible clusters from seven screening centers. In the intervention group, participants from high-risk areas were screened by endoscopy; in non-high-risk areas, high-risk individuals were identified using a questionnaire and advised for endoscopy. Lugol's iodine staining in esophagus and indigo carmine dye in stomach were performed to aid in the diagnosis of suspicious lesions. The primary outcomes of this study were the detection rate (proportion of positive cases among individuals who underwent endoscopic screening) and early detection rate (the proportion of positive cases with stage 0/I among all positive cases). Results: A total of 149,956 eligible subjects were included. The detection rate was 0.7% in esophagus and 0.8% in stomach, respectively. Compared with non-high-risk areas, the detection rates in high-risk areas were higher, both in esophagus (0.9% vs. 0.1%) and in stomach (0.9% vs. 0.3%). The same difference was found for early-detection rate (esophagus: 92.9% vs. 53.3%; stomach: 81.5% vs. 33.3%). Conclusions: The diagnostic yield of both esophagus and stomach were higher in high-risk areas than in non-high-risk areas, even though in non-high-risk areas, only high-risk individuals were screened. Our study may provide important clues for evaluating and improving the effectiveness of upper-endoscopic screening in China.