Is there publication bias in the reporting of cancer risk in Barrett's esophagus?

Background & Aims: The published risk of adenocarcinoma in the setting of B arrett's esophagus (BE) varies. Publication bias, the selective reporting o f studies featuring positive or extreme results, may result in overestimati on of this cancer risk in the literature. The aim of this study was to asse ss those publications reporting a cancer risk in BE for evidence of publica tion bias. Methods: A MEDLINE search for all published estimates between 19 66 and 1998 of cancer risk in BE was performed. All studies reporting a can cer risk expressible in cancers per patient-year of follow-up were retrieve d. Bibliographies of these studies were surveyed for additional estimates. All publications that required an initial endoscopy with histologic confirm ation of BE and any cancer were included. The relationship of reported canc er risk to size of the study was assessed, Multivariable regression control ling for differences in definition of BE, as well as other study characteri stics, was performed. The data were also analyzed by means of a funnel diag ram, an epidemiologic method to assess publication bias. Results: Five hund red fifty-four abstracts were reviewed. Twenty-seven publications met the s tated criteria for inclusion. There was a strong correlation between cancer risk and the size of the study, with small studies reporting much higher r isks of cancer than larger studies. This association persisted when differe nces in the definition of BE, retrospective vs. prospective nature of the s tudy, surveillance interval, and the effect of cancer detected in the first year were considered. The funnel diagram analysis suggested publication bi as. Conclusions: The cancer risk in BE may be overestimated in the literatu re due to publication bias.