Publication bias does not play a role in the reporting of the results of endoscopic ultrasound staging of upper gastrointestinal cancers

Background and study aim: An overestimation of the accuracy of endoscopic ultrasound (EUS) results in rectal cancer staging has been reported recently, which was found to be caused by the selective reporting of more positive results. In this study, we assessed whether publication bias was also present in the reporting of EUS staging results in upper gastrointestinal cancer. Methods: A Medline literature search was performed. English-language articles containing information on the accuracy of EUS for T staging and/ or N staging of esophageal, gastric, and pancreatic cancer were included. Articles published in abstract form only, case reports, and reviews were excluded. Studies reporting EUS results of patients who had undergone preoperative radiation and/or chemotherapy were also excluded. EUS results were plotted against numbers of patients, year of publication, journal type, and journal impact factor. Results: The plots of the numbers of patients against accuracies for T stage and N stage and the statistical analyses showed no evidence of publication bias with regard to upper gastrointestinal cancer. The reported accuracy of EUS for the T stage of esophageal, gastric, and pancreatic cancer declined slightly over the years, but this was statistically significant only in the case of esophageal cancer (P = 0.01). No statistically significant correlations were found for N staging for any of the three types of cancer. In addition, no correlations were found between EUS results and journal type or journal impact factor. Conclusion: No evidence was found for the selective reporting of more positive EUS results for esophageal, gastric, and pancreatic cancer staging, which suggests that publication bias was not present.