Literature search strategy

A literature search of the following databases (from inception to December 2019) was performed by two authors to identify eligible studies: PubMed, Embase, Web of Science, ClinicalTrials.gov, the Cochrane Library, Chinese Biology Medicine, China National Knowledge Infrastructure and the Wanfang Data Knowledge Service Platform. Furthermore, a manual search using the reference lists of all the retrieved articles and relevant journals was conducted to identify additional eligible studies. Unpublished studies were retrieved from the System for Information on Grey Literature database to reduce publication bias. Combinations of Medical Subject Headings/Emtree terms and free-text terms were used to search the above databases. The location of the primary OC site included typical endoscopic measurements of each region from the incisors (range: from 15 to 42 cm), starting from the upper oesophageal sphincter to the proximal 2 cm of the cardia.²³ The following main search terms were used: ‘oesophageal neoplasms’, ‘epidermal growth factor receptor inhibitor’, ‘cetuximab’, ‘panitumumab’, ‘nimotuzumab’, ‘erlotinib’, ‘gefitinib’, ‘randomised controlled trial’ and ‘clinical trial’. The full search strategies used are presented in online supplemental data S1.

bmjopen-2020-046352supp001.pdf

Two authors independently screened the studies based on the selection criteria. Initially, each title and abstract were screened, and the full text of the eligible studies was retrieved. Any disagreements between the two authors during the selection process were settled by discussion and consensus with a third author.