Endoscopy screening effect on stage distributions of esophageal cancer: A cluster randomized cohort study in China

Efficacy of endoscopic screening for esophageal cancer is not sufficiently definitive and lacks randomized controlled trial evidence. The present study proved short‐term screening efficacy through describing and comparing disease stage distributions of intervention and control populations. Villages from Linzhou and Cixian were cluster randomly allocated to the intervention or to the control group and the target population of 52 729 and 43 068 individuals was 40‐69 years old, respectively, and the actual enrolled numbers were 18 316 and 21 178, respectively. TNM stage information and study‐defined stage information of esophageal cases from 2012 to 2016 were collected. Stage distributions were compared between the intervention and control groups in the total target population, as well as in the subgroup populations in terms of enrolment and before or after intervention. There were a total of 199 and 141 esophageal cancer cases in the intervention and control groups, respectively. For the target population, distributions of TNM stage were borderline significant between the two groups after intervention (P = .093). However, subgroup analysis of the enrolled population during the after‐intervention period had statistical significance for both TNM and study‐defined stage. Natural TNM stage distributions were approximately 32%, 41%, 24% and 3% for stages I to IV vs 71%, 19%, 7% and 3% in the intervention population. The natural study‐defined stage distributions from early, middle to advanced stages were approximately 18%, 49% and 33% vs 59%, 33% and 8%. Early‐stage esophageal cancer cases accounted for a higher proportion after endoscopy screening, and the efficacy in the target population depends on the intervention compliance. Other than incidence and mortality as endpoints, in the present cluster randomized controlled study, we took distributions of disease stage (TNM stage) as the short‐term endpoint in order to evaluate the effect of esophageal cancer screening by endoscopy. The results provided real‐world data of stage distributions from the natural population. However, the change of stage distributions proved the short‐term efficacy of endoscopy screening from another perspective.