Milea Timbergen

327 (Inter)national Case Registration In order to increase the availability of biomaterials accurate identification and registration of patients is a necessity. As the disease is not classified as a cancer 7 , cases are not registered in the Dutch national cancer registry. Currently, our research is depending on the Dutch national pathology database: Pathologisch-Anatomisch Landelijk Geautomatiseerd Archief (PALGA) 8 . This registry provides pathology reports, but contains little clinical information, and results can be distorted due to the use of general terms like “fibrosis”. Furthermore, obtaining clinical data is challenging as patients are often referred to their local hospitals for initial diagnosis before referral to one of the seven Dutch sarcoma-expertise clinics. This could lead to fragmentation of patient data, as the first diagnostic specimen remains in the local hospital, whilst data of additional molecular analysis and the clinical data are localized in the expert clinic. Currently, both pathological analysis (first diagnosis and additional molecular analyses) are registered separately in PALGA, and patient linkage is not always possible. This type of registration leads to missing data or incorrect data interpretation. Especially due to the rarity of the disease, a complete registration system to identify patients and their diagnostic pathways on a national level must be possible. This national registry could be complemented by an imaging database, such as the radiomics platform, in order to recognize patters on imaging, to predict clinical behaviour. Several worldwide initiatives have been made to improve the registration process of DTF cases. For example, the American patient association, the Desmoid Tumor Research Foundation (DTRF), developed the DTRF registry 9 . This patient registry is an online system completed by patients, and designed to understand patients’ experiences and the natural history of DTF. The French sarcoma network has also made tremendous efforts to improve registration by including DTF patients in the national sarcoma registry 10 . This effort decreased the number of misdiagnosis, shortened the diagnostic delay, and increased the number of patients treated in an expert centre 11 . Accurate case registration would aid translational research projects by identification of biomaterial available for research purposes. Clinical research would benefit by quick identification of eligible patients for both retrospective and prospective studies. Additionally, such a registration would be helpful for quick and clear communication about important research updates and it will assist international collaborations. Therefore, a national DTF registration system is advised. 12