518 chapter 13 Diagnostic misconception and misestimation The primary motivation to participate in a clinical trial is often the patients’ hope to benefit themselves. The second motivation is likely altruism – the desire to help other patients by contributing to medical research [769]. In therapeutic oncology trials, patients are frequently offered trial participation in a palliative setting when other established therapy options have failed, leaving them feeling helpless and distressed. The possibility of trial participation then offers hope, although research may also be misinterpreted as therapy by these patients [769]. This is defined as therapeutic misconception and may be distinguished from therapeutic misestimation, i.e., underestimating the risks and/or overestimating the benefits of clinical trial participation, and therapeutic optimism, i.e., hoping for the best personal outcome [770-772]. In light of research ethics, both therapeutic misconception and therapeutic misestimation can be considered problematic, although it is widely assumed that both do facilitate trial recruitment. Recognition of one’s own therapeutic misconception at a later stage during trial participation may even result in trial dropout [773]. With similar definitions, diagnostic misconception and diagnostic misestimation may apply to diagnostic trials [774, 775]. During informed consent procedures, investigators have the obligation to adequately inform potential trial participants about the scientific purpose of the trial and the risk-benefit ratio. The latter for example also includes openly informing the patients about any study procedures that solely serve research purposes and the possibility of any uncertainty caused by limited knowledge of the test or treatment under investigation [769-771]. The effects of diagnostic misconception and misestimation in combination with the suspense of blinding have also been observed during the EfFECTS trial. As discussed in the previous section on selection bias, patients hoping for a negative [18F]FDG-PET/CT scan and active surveillance were probably more likely to participate in the trial, potentially underestimating the chance of having an [18F]FDG positive nodule. We have experienced discontent about trial participation in several patients when they were informed after the [18F]FDG-PET/CT scan that their recommended management was not what they had hoped for: diagnostic surgery. To clearly illustrate what one could expect from trial participation prior to recruitment, the EfFECTS trial patient information contained a simplified infographic (Figure 1). This was used to explain that six out of seven patients with a diagnostic surgery advice would receive this advice because of an [18F]FDG positive nodule (based on a 63% [18F]FDG positive rate [38]) with a consequent 39% risk of malignancy, as compared to only one in seven of these patients who would receive this advice because he/she was randomized to the control arm with an [18F]FDG negative nodule. From personal experience, without exception, all patients who were discontented about their diagnostic surgery advice believed that they were the unlucky latter. This even resulted in a small number of angry patients demanding to see the results of their randomization and/or [18F]FDG-PET/CT
RkJQdWJsaXNoZXIy MTk4NDMw