Milea Timbergen

246 Abstract Background Desmoid-type fibromatosis (DTF) is a rare, non-metastasising soft tissue tumour. Symptoms, unpredictable growth, lack of definitive treatments, and the chronic character of the disease can significantly impact health-related quality of life (HRQoL). We aimed to identify the most important HRQoL-issues according to DTF patients in two countries, in order to devise a specific HRQoL-questionnaire for this patient group. Methods DTF patients and health care providers (HCPs) from the Netherlands and the United Kingdom individually ranked 124 issues regarding diagnosis, treatment, follow-up, recurrence, living with DTF, healthcare and supportive care experiences, according to their relevance. Descriptive statistics were used to calculate priority scores. Results The most highly ranked issues by patients (n = 29) 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’ with mean (M) scores of 3.0, 2.9 and 2.8 respectively (Likert scale 1-4). British patients scored higher on most issues compared to Dutch patients (M 2.2 vs. M 1.5). HCPs (n = 31) gave higher scores on most issues compared to patients (M 2.3 vs. M 1.8). Conclusions This study identified the most relevant issues for DTF patients, which should be included in a DTF-specific HRQoL-questionnaire. Additionally, we identified differences in priority scores between British and Dutch participating 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. 9