European Society for Medical Oncology (ESMO) 2018 Congress Twitter analysis: from ethics to results through the understanding of communication and interaction flows.

Twitter is a microblogging service providing a platform for social networking. For medical information, Twitter is an interesting channel for sharing and spreading information and as an engagement platform for different stakeholders. Benefits and caveats of uncontrolled medical information must be carefully pondered, considering the possible intended and unintended adverse outcomes of uncontrolled influencing. The aim of this study was to describe the non-commercial content shared on Twitter and to analyse the level of influence of commercial tweeters during the European Society of Medical Oncology (ESMO) 2018 annual meeting held in Munich. A retrospective analysis of the tweets shared in the period 19-23 October 2018 indexed with the hashtag #ESMO18 or #ESMO2018 was performed; methodology of systematic reviews was mirrored. Commercial tweeters (pharmaceutical and biotechnology companies, device manufacturers and spam tweeters) were excluded from the primary analysis, and only non-commercial tweets from and about the congress were included. Tweets were analysed using a network analytical tool (NodeXL). A total of 7100 tweets posted by 1334 tweeters were identified for the period of interest. Less than 10% of tweeters were identified as commercial, posting 15.7% of tweets and receiving almost one-quarter of retweets. However, pharmaceutical and biotech tweeters were substantially less likely to be mentioned by other tweeters. All of the top 10 retweeters of non-commercial content were clinicians and/or professional organisations, in stark contrast with the commercial content. The use of social networks in medical meetings, including oncology, is increasing for real-time communication and informed opinion-making. The uncontrolled spread of information on Twitter can both stimulate discussions on non-official and non-canonical channels of communication and provide uncontrolled influencing of diverse stakeholders. The disclosure of financial declarations of interest on Twitter could enhance the transparency of the information, as is already happening in medical journals