Recently, there has been increasing interest in methodological aspects of advanced imaging, including the role of guidelines, recommendations, and experts' consensus, the practice of self-referral, and the risk of diagnostic procedure overuse. In a recent Delphi study of the European Association for Nuclear Medicine (EANM), panelists were asked to give their opinion on 47 scientific questions about imaging in prostate cancer. Nine additional questions exploring the experts' attitudes and opinions relating to the procedure of consensus building itself were also included. The purpose was to provide insights into the mechanism of recommendation choice and consensus building as seen from the experts' point of view. Results: Regarding the factors likely to influence the willingness to refer a patient for imaging, the most voted were incorporation into guidelines and data from scientific literature, while personal experience and personal relationship were chosen by a small minority. Regarding the recommendations more relevant to prescribe an imaging procedure, it resulted the incorporation into guidelines promoted by scientific societies (59% of votes); these guidelines also resulted the more trusted. With respect to patients' preferences considered when prescribing an imaging procedure, the most voted was accuracy, resulted more important than easy access and time to access to the procedure. The majority of the experts expressed the opinion that there is a scarce use of imaging procedures in prostate cancer. With respect to the most relevant factor to build consensus, it resulted the transparency of the process (52% of votes), followed by multidisciplinarity of contributors. The main obstacle to incorporation of modern imaging procedures into guidelines resulted the lack of primary literature on clinical impact. Conclusions: Firstly, the panelists portray themselves as having Evidence-Based Medicine oriented and scientifically inclined attitudes and preferences. Secondly, guidelines and recommendations from scientific societies, especially clinical ones, are positively taken into account as factors influencing decisions, but panelists tend to consider their own appraisal of the scientific literature as more relevant. Thirdly, in respect of overuse, panelists do not think that advanced diagnostic procedures are overutilized in the specific case of Prostate Cancer, but rather they are underutilized.
Keywords: consensus; epistemology; guidelines; nuclear medicine; overutilization; prostate cancer.