Milea Timbergen

249 identified using the website Orphanet, which provides information on centres of expertise dedicated to the medical management for rare diseases (https://www.orpha.net/consor/cgi- bin/Clinics_Search.php?lng=EN). In the UK, HCPs of the aforementioned disciplines were identified using the sarcoma network group of the Royal Marsden Hospital, London, UK. Every HCP received an invitation email with a token and link to the e-survey. A reminder was sent after one week if the HCP had not responded. Sociodemographic and clinical characteristics Age at time of diagnosis was either stated by the patient or calculated using the date of birth and date of the first pathology report. Age at the time of questionnaire completion was either stated by the patient or calculated using the date of informed consent and the date of birth. Education levels were categorized into “high” (PhD, university, higher education postgraduate/undergraduate degree), “intermediate” (professional qualification, vocational work, work related qualification, general secondary education, further/intermediate education), and “low” (primary education [with a higher, but not completed education] and secondary education). Continuous variables were presented as a mean with a standard deviation (SD) or as a median with an interquartile range (IQR). Categorical variables were presented as numbers ( n ) using frequencies and percentages. Presentation of issues to patients and health care providers A total of 124 issues were presented to patients and health care providers (HCPs) in a random order (Supplemental Table 1). Patients and HCPs scored 124 issues by relevance on a Likert scale from 1 to 4 ((1) not at all, (2) a little, (3) quite a bit, and (4) very much) and ranked the top ten most important issues. The frequency that each issue appeared in the top ten most important issues was converted into the mean priority score (M-score) per issue. The frequency of top ten priority score of each issue was calculated and ranked in overall priority score. Where questions were left blank by the participant, they were coded as a “missing value” and not incorporated in the total score. Space for general remarks was available at the end of the questionnaire. EORTC QLQ-C30 questionnaire In addition to the issue list, patients were asked to fill out the 30-item EORTC QLQ- C30 questionnaire (version 3) to assess HRQoL 15 . Norm data was obtained from the EORTC, which recently collected data from the general population in Europe and North America 16 . Only data from the general population in the Netherlands and the UK were used for the current study. The EORTC QLQ-C30 questionnaire contains five functional 9