Milea Timbergen

254 Overall, British patients gave higher scores for each issue compared to Dutch patients (M-score 2.2 (UK) vs M-score 1.5 (NL)) (Supplemental Table 4). Differences in score of more than 1 point between Dutch and British patients are displayed in Supplemental Figure 1. Additionally, priority scores of Dutch and British HCPs, and scores of participating patients and HCPs from the Netherlands and the UK were compared (Supplemental Table 4). The total cohort of patients was too small to identify any differences between subgroups (e.g., initial treatment type, tumour location, and age at diagnosis). Health care providers In the Netherlands, HCPs were invited at six sarcoma centres. All HCPs from the UK were employees at the Royal Marsden Hospital, London. Twenty-one Dutch and ten British HCPs responded. Professional backgrounds included; surgical oncologist (n = 12), medical oncologist (n = 6), radiation oncologist (n = 5), specialized sarcoma nurse (n = 5), and other professions including a radiologist, physiotherapist and pain specialist (all n = 1). Seventeen professionals had more than 10 years of experience, three had 6-10 years of experience, and eleven had 5 or less years of experience working with desmoid patients. Frequency of contact with DTF patients varied between once a week (n = 9, 29%) to rarely (less than once every 3 months) (n = 1, 3%). Issues with the highest scores according to HCPs included; “worries about tumour growth” (M-score 3.4), “stress about the diagnosis” (M-score 3.2), “the experience of uncertainty during the course of the disease” (M-score 3.2), “pain” (M-score 3.2), “concerns about the future” (M-score 3.0), “stress around check-ups during the follow-up” (M-score 3.0), “fear of recurrence after treatment” (M-score 3.0), “fear of tumour growth/tumour growth into adjacent tissues or organs” (M-score 2.9) and “the feeling that patients do not have a clear prognosis” (M-score 2.9). Overall, HCPs from the UK gave higher scores, compared to Dutch HCPs with M-scores of 2.8 and 2.0 respectively (Supplemental Table 4). Participating patients versus health care providers There was considerable overlap between the highest ranked issues according to patients and HCPs, particularly regarding the unpredictable growth pattern of DTF tumours (Supplemental Table 4). HCPs scored significantly higher (p < 0.05) on 77 out of a total of 77 of 124 issues. HCPs also gave a higher mean overall score on the issues list (total M-score 2.3) compared to patients (total M-score 1.8) (Supplemental Table 4). 9