(P 386) SOLITARY FIBROUS TUMOUR: A DANISH SAMPLE FROM 2013 – 2018

Objective: Solitary fibrous tumour (SFT) is a rare soft tissue tumour with malignant potential that can arise throughout the body. Around 10 – 30% of patients diagnosed with SFT experience relapse despite successful surgical treatment and risk of recurrence is notoriously difficult to predict. In order to collect a complete and high-quality case-series on SFT patients, we identified all Danish patients operated for extra-meningeal SFT from 2013 – 2018.

Methods: We included all Danish adults with a histologically proven extra-meningeal SFT diagnosed between 2013 - 2018. Data was provided through the unique Danish Pathology Register and the Danish Sarcoma Database. An experienced sarcoma pathologist evaluated the histological reports and histological mimics were excluded. We chose to focus on patients with localized SFT who had an intended curable resection in order to estimate the risk of recurrence. Complete follow-up was achieved and clinical data was retrieved through the patients’ medical reports.

Results: Sixty-two patients were operated for SFT in various anatomic regions of the body. Forty-eight percent were male, median age at diagnosis was 59 and the majority of patients were ASA-score 2 (63%). Most SFTs were situated in the head and neck region (21%) and in the chest/thorax (21%) followed by extremities (19%), abdomen (16%), retroperitoneum (15%) and the pelvis (8%). Most patients had successful resection performed, however one patient died due to respiratory failure after thoracotomy. Sixty percent had R0 resection, 21% had R1 resection and 19% could not be estimated. Risk of recurrence was estimated with both the Demicco-revised score and the G-score. The G-score seemed to perform better in terms of predicting recurrence. Twelve patients (19%) developed local recurrence or metastasis 10 of these died due to tumour spread after receiving either palliative chemo- or radiotherapy.

Conclusion: We hereby present a Danish cohort of 62 patients operated for extra-meningeal SFT from 2013 -2018. Total recurrence-rate was 19%, however this number is expected to rise since recurrence may occur later than the follow-up time of this study. Surgery is the only potentially curable treatment of localized SFT, even though radical resection may be difficult to achieve.