Milea Timbergen

235 to the preferred tool, as a DTF specific tool has not been developed yet. One could argue that a combination of the aforementioned scores could be sufficient to get a clear view of relevant issues of DTF patients. A downside to this might be that patients are exposed to a large number of questions, which could be non-relevant and give patients an additional burden. A carefully developed DTF-specific tool could be effective in measuring HRQoL. There are limitations to the current systematic literature review. Since DTF is a rare soft tissue tumour, included studies comprise retrospective, small sized studies with low methodologic quality. Additionally, risk of bias could not be assessed properly. To create a HRQoL-tool which is suitable for DTF patients and to achieve at least satisfying content validity, focus groups were used which encouraged participants to discuss their views on HRQoL-issues 46 . Our focus group results suggest that patients with DTF often face problems with recognition and management because of the lack of diagnostic awareness, as a result of its rarity, and because of the striking discrepancy between its benign histological appearance and its local aggressive behaviour. This study identified key issues in six themes; 1) diagnosis, 2) treatment, 3) follow-up and recurrence, 4) physical domain, 5) psychological and emotional domain and 6) social domain, which will be the basis of a future DTF- specific tool. The first three themes (diagnosis, treatment and follow-up) can be clustered as ‘the process of healthcare’ and the last three themes (physical domain, psychological and emotional domain and social domain) can be clustered as ‘symptoms and function’. We do acknowledge the overlap that can occur between themes. The need to gain more insight into HRQoL of DTF patients is reflected by several attempts made around the world. In the USA, the Desmoid Tumor Research Foundation (DTRF) patient registry opened recently (September 2017) to register clinical, pathological and geographical variables of DTF patients. Additionally, a survey, based on both validated and non-validated HRQoL-questionnaires, was put together to gain more insight in HRQoL of DTF patients 47 . The latter, a PRO specific DTF-tool, was presented on the Annual Meeting of the American Society of Clinical Oncology of 2017 48 . In the Royal Marsden UK, two focus group sessions took place in March 2017 23 . This resulted in four key themes (diagnostic pathway; treatment pathway; living with DTF; supportive care). We found an interesting difference in the impact of DTF between the Dutch and UK focus group participants. Apart from the selection bias, which could be explained by the selection of patients and the willingness of patients to participate in such a study, and differences in the way patients had been treated with more often chemotherapy (Caelyx) in the UK focus 8