(P 391) VISCERAL ANGIOSARCOMA: A NATIONWIDE STUDY WITH LONG-TERM FOLLOW-UP

Objective: Angiosarcoma originate from vascular cells, and rarely lymphatic endothelial cells, hence Angiosarcoma can arise at any anatomic site. Visceral angiosarcoma are predominantly located in the liver and spleen, and are aggressive high-grade tumors with considerable risk of local recurrence, metastasis and poor overall survival. Nationwide studies reporting complete and long-term follow-up of patients with visceral angiosaroma are scarce, but aid to existing evidence for this aggressive sarcoma type. The aim of our study was (1) to describe a consecutive national cohort of patients diagnosed with visceral angiosarcoma; (2) to estimate long term overall survival, risk of local recurrence, and metastasis; and (3) to analyze risk factors for overall survival, local recurrence, and metastasis.

Methods: We included all adult patients in Denmark with a histologically proven visceral angiosarcoma diagnosed between 2000 - 2017. Data were provided through the unique Danish Pathology Register and the Danish Sarcoma Database, which provide nationwide and complete data on visceral angiosarcoma. We obtained data on age, sex, comorbidity, symptoms, diagnosis, location, treatment, complications, recurrence and survival from the registries and health journals.

Results: We identified 17 patients with visceral angiosarcoma during a 17-year period, which equals to an incidence of 1 patient /5.5 million inhabitants per year. Extracted data will be presented. Recurrence- and metastasis free survival as well as disease-specific death were calculated as well as survival curves, and will be presented.

Conclusion: We performed a nationwide study on visceral angiosarcoma identifying only 17 patients during a 17-year period in a population of 5.5 million inhabitants (1 patient/ 5.5 million inhabitants per year). By obtaining data from the Danish Pathology and The Danish Sarcoma Registries we were able to perform a complete nationwide study with complete long-term follow-up for patients suffering from this rare aggressive disease. This data can add to existing knowledge regarding incidence, treatment and prognosis.