Mariken Stegmann

making a decision. 2 Most research concerning SDM in patients with cancer has focused on improving advanced care planning and documentation. 35 However, evidence about clinical outcomes in this patient group is scarce. In a systematic review summarising the effects of SDM on distress and health care utilisation for patients with lung cancer, 36 studies were only found in which SDM was part of broader supportive care interventions. This made it impossible to draw conclusions about the effect of SDM alone. Nevertheless, positive effects were reported in favour of the intervention groups in studies using anxiety ‐ specific measures or depression ‐ specific measures. 36 Evidence for reductions in health care utilisation were also found in five studies. 36 SDM in primary care To date, most research into the effects of SDM for patients with cancer has been performed in secondary care. The OPTion study (Chapters 2 to 5), which was based in primary care, therefore adds valuable information. For example, we showed that an OPT conversation with the GP had no significant effect on patient empowerment, but that it did improve symptoms of anxiety. This may have occurred because patients who are more engaged in the treatment decision felt more in control and less anxious. It is also possible that the conversation itself helped to reduce anxiety by giving the patient an opportunity to share feelings and receive emotional support from the GP. This is consistent with the observation in NFK GP/nurse survey that 82% of patients wanted their GP to listen to their worries and fears. 14 No negative effects of SDM were identified in the OPTion study (Chapter 4). However, a recent study in primary care detected that there was less perceived SDM in the intervention group after a time ‐ out consultation with the GP in which treatment goals were discussed. 30 According to the authors, this could be explained by the timing of the conversation, which due to logistical problems, was typically after the treatment decision had made. Literature about the effects of SDM on health care professionals is scarce. One systematic review concluded that decision aids can improve a health care provider’s satisfaction with medical decision ‐ making and provide helpful information. 37 In the OPTion study (Chapter 4), one ‐ third of participating GPs indicated that the OPT conversation had given them new insights into the patient, including their treatment goals and preferences for end ‐ of ‐ life care (advance care planning). In another study with a similar intervention, GPs experienced more appreciation and information from the hospital, leading to greater involvement in guiding the patient. 29 Methodological Challenges Although the strengths and limitations specific to the study are presented in each Chapter, I would like to draw the reader’s attention to some important methodological challenges that should be considered in greater detail. Chief among these are the challenges in research among patients with non ‐ curable cancer, as well as the challenges specific to research about medical communication. Research among patients with non ‐ curable cancer Patients with non ‐ curable cancer will probably die because of their cancer, but new therapies mean that some patients can survive for many years. Nevertheless, as shown in the OPTion study (Chapter 4), many of the 145 included patients deteriorated (n = 12) or died (n = 8) within only a few weeks. It is therefore unsurprising that 44 of the 268 patients 112 Chapter 8