Pazopanib As First Line Treatment for Solitary Fibrous Tumours: the Royal Marsden Hospital Experience

Background: Solitary Fibrous Tumour (SFT) is a rare soft tissue neoplasm, described in several locations in the body. It is classified as intermediate malignant potential with low risk of metastasis and has a low tendency to recur after primary surgery.

Methods: We performed a prospective data collection of the patients with SFT presented to the Royal Marsden Hospital from January to December 2013, and treated with pazopanib in first line. Demographics, anatomic primary sites, treatment and survival outcomes were collected from patients' electronic records.

Results: 13 patients (54% females) were identified with a median age of 51 years (range 37-77). Most of the patients (77%) were diagnosed with extra-thoracic SFT. All the patients received first line treatment with pazopanib for metastatic disease. Median overall survival (OS) was 13.3 months. Median progression free survival (PFS) was 4.7 months. No statistically significant difference was found in OS and PFS between primary thoracic SFT and primary extra-thoracic SFT. According to RECIST, one partial response (9%) and eight disease stabilizations (73%) were found as best responses. Using Choi criteria, there were 5 partial responses (46%) and 4 stabilizations (36%).

Conclusion: Our prospective data confirm that anti-angiogenic drugs are active in SFT. PFS and overall response do not appear significantly lower than other reported series on the same disease. Furthermore, pazopanib is a drug already licensed in soft tissue sarcomas and these data suggest its activity also in this particular subtype of sarcomas.