Milea Timbergen

337 In Chapter 9 , we used the results of chapter 8 and the corresponding study from the United Kingdom (UK) of Husson et al. (2018, Support Care Cancer) to create a list of issues regarding diagnosis, treatment, follow-up, recurrence, living with DTF, healthcare and supportive care experiences. DTF patients and health care providers (HCPs) from the Netherlands and the UK individually ranked 124 issues according to their relevance. The most highly ranked issues by 29 patients were issues concerning “tumour growth”, “feeling that there is something in the body that does not belong there”, and “fear of tumour growth into adjacent tissues or organs”. British patients scored higher on most issues compared to Dutch patients and 31 HCPs gave higher scores on most issues compared to patients. Field- testing in a large, international cohort is needed to confirm these findings and to devise a comprehensive and specific HRQoL-questionnaire for DTF patients. Chapter 10 describes the protocol of the QUALIFIED study (The evaluation of health- related quality of life issues experienced by patients with desmoid-type fibromatosis), an international, multicentre, cross-sectional, observational cohort study. The DTF-specific questionnaire, the DTF-QOL supplements existing questionnaires such as the European Organization for Research and Treatment for Cancer Quality of Life Questionnaire (EORTC QLQ-C30), and the EuroQol 5D (EQ-5D) and questionnaires compiled specifically for this study to gather sociodemographic and clinical characteristics. All adult (≥18 years) patients diagnosed between January 1990 and October 2019, with pathologically proven, sporadic DTF and a recent (between October 2014 and October 2019) visit to the hospital for their DTF are eligible for inclusion. Questionnaires will be completed using PROFILES (Patient Reported Outcomes Following Initial treatment and Long term Evaluation of Survivorship), a system to electronically capture questionnaire responses. It aims to gain insight into DTF-specific HRQoL-problems, to compare HRQoL-scores of DTF patients in the general Dutch and British population; and to identify subgroups at risk for impaired HRQoL. 13