Enrico Martin

91 Oncological treatment considerations Study population Several national and international surgical societies were asked to distribute the survey among their members with an accompanying text explaining the purpose of the research. Surgeons involved in the surgical management of MPNSTs were asked to fill out the survey. A reminder email was sent thereafter. The survey was sent to the members of the Dutch Society of Surgical Oncology (NVCO), the Dutch Society for Surgery of the Hand (NVVH), the peripheral nerve section of the Dutch Society for Neurosurgery (NVVN), the American Society for Peripheral Nerve (ASPN), the peripheral nerve section of the European Association of Neurosurgical Societies (EANS), and the Soft Tissue and Bone Sarcoma Group of the European Organization for Research and Treatment of Cancer (EORTC). Survey responses were filled out anonymously and no person identifying data was inquired. Statistical analysis Responses were summarized per surgical subspecialty: oncologic surgery, neurosurgery, plastic surgery, and other surgical subspecialties. Differences were calculated with χ 2 -tests for categorical data. P-values <0.05 were considered statistically significant. Statistical analyses and data visualization were conducted using R version 3.6.0 (R Core Team, 2019). Results Demographics of survey responders In total, 174 respondents filled out the survey: 30 surgical oncologists, 30 neurosurgeons, 85 plastic surgeons, and 29 surgeons from other surgical subspecialties. Most respondents were European ( Figure 1 ). The ‘other’ surgical subspecialty group consisted mainly of non-oncologic orthopedic surgeons and general surgeons with a hand surgery subspecialization. The largest proportion of surgeons had less than 10 years of experience as a consultant surgeon (38%, Table 1 ). Fellowship experience differed between subspecialties (p<0.001); surgical oncologists commonly had completed a sarcoma fellowship (85%), while other respondents more commonly did a fellowship in peripheral nerve surgery (32-56%). Highest caseloads were performed by surgical oncologists (p<0.001). The majority of respondents operated extremity site tumors (87%, p>0.05), but most other tumor sites differed between surgical subspecialties. 5