Ietje Perfors

183 However, we chose to randomise on patient level to ensure optimal comparison of study arms. Therefore, we used a conventional RCT design. We found little contamination in the GRIP trial. Recently, action research is suggested in case the intervention under study is not yet optimal. 13 In action research, interventions are iteratively improved during the course of research, by continuous adaptations to local settings. In case a format is found that seems to include all the basic elements for success, a rigid but robust RCT design could be the next step. TheMRC framework also recommends to assess cost-effectiveness. As we did not find positive effects when considering the primary outcomes, the cost- effectiveness analysis was omitted. For future interventions, we think that cost-effectiveness analyses are important since they provide vital arguments to (not) adopt policy changes. For such analyses, we advise a combination of questionnaires and healthcare registry extractions, to complement each other for the assessment of healthcare use. We used the iMTA-PCQ questionnaire for productivity costs and medical records for healthcare use, and found that these sources of information complement each other. 4. Implementation Although the results do not allow large scale implementation of the GRIP intervention, some important lessons can be learned for future implementation of TOC and primary care involvement in clinical practice. If future implementation of primary care involvement in cancer care is aimed for, broad support should be created to change the healthcare pathway where necessary and to strive for a more integrated and collaborative approach between healthcare professionals. The MRC framework states that “Successful implementation depends on changing behaviour –often of awide range of people. This requires a scientific understanding of the behaviour that needs to change, the factors maintaining current behaviour and barriers and facilitators to change”. 6 In the GRIP RCT we aimed for integrated cancer care 7