Solitary Fibrous Tumor - Short Description

1. Solitary Fibrous Tumor
Kiron G

2. Solitary fibrous tumors (SFTs)
• Solitary fibrous tumors (SFTs), also known as localized fibrous tumors
or fibrous mesotheliomas, are rare spindle cell neoplasms first
reported as arising from the pleura.
• Solitary fibrous tumors from all anatomic sites usually follow a benign
clinical course; however, SFTs can recur and metastasize after surgical
resection.
• with equal frequency in men and women.
Gold, J.S., Antonescu, C.R., Hajdu, C., Ferrone, C.R., Hussain, M., Lewis, J.J., Brennan, M.F. and Coit, D.G. (2002), Clinicopathologic correlates of solitary fibrous tumors.
Cancer, 94: 1057-1068. https://doi.org/10.1002/cncr.10328

3. • incidence of about 0.2 in 100,000 per year
• seen in patients of all ages but predominantly in the fifth and sixth
decades of life
• usually present as slowly growing masses causing symptoms owing to
local compression and/or metastatic disease that can also affect the
bone
Radiation Therapy as Sole Management for Solitary Fibrous Tumors (SFT): A Retrospective Study From the Global SFT Initiative in Collaboration With the Sarcoma
Patients EuroNet

4. Histologically, SFTs can be subdivided into
• Typical - mitotic count < 4),
• Malignant - mitotic count >5, and
• Dedifferentiated variants
• SFT is consistently associated with NAB2-STAT6 gene fusions arising
from recurrent intrachromosomal rearrangements on chromosome
12q
Radiation Therapy as Sole Management for Solitary Fibrous Tumors (SFT): A Retrospective Study From the Global SFT Initiative in Collaboration With the Sarcoma
Patients EuroNet

5. • Lesions tend to present as slowly growing painless masses or may
generate symptoms due to mass or pressure effects on adjacent
structures.
• Uncommonly, FT can present with symptoms of hypoglycemia due to
secretion of insulin-like growth factors.
• The etiology of SFT remains unknown, and no association has been
demonstrated with environmental factors such as tobacco
consumption or asbestos exposure.

6. Radiology
• these are often large, well-defined, lobulated, solid, and vascular
masses, often with prominent feeding vessels or sometimes a visible
fatty component, which displace adjacent structures.
• Radiologic features correlating better with malignancy have included
tumor size, heterogeneous signal intensity, and heterogeneous
contrast uptake on magnetic resonance imaging

8. • While the majority of SFTs with classical morphologic features behave
in an indolent manner, the behavior of SFT is unpredictable.
• SFTs that have overtly malignant histologic features tend to be
aggressive neoplasms that behave as high-grade sarcomas.
• Dedifferentiation in SFT is associated with a worse prognosis

9. TREATMENT
• standard treatment of primary localized SFTs is wide surgical
resection.
• estimated recurrence rates for malignant SFTs are around 30%.

10. Radiotherapy
• surgery plus postoperative RT revealed a significant benefit favoring
RT in local control.
• no significant benefit was seen for OS.
• SFT cases at the limit of resectability, or those cases in which a
marginal resection is foreseen, especially those cases with a high
mitotic rate, could benefit from neoadjuvant RT

11. The Role of Postoperative Radiotherapy in Intracranial
Solitary Fibrous Tumor/Hemangiopericytoma: A Multi-
institutional Retrospective Study (KROG 18-11)
• A total of 133 patients with histologically confirmed HPC were included from
eight institutions.
• Gross total resection (GTR) and subtotal resection (STR) were performed in 86
and 47 patients, respectively. PORT was performed in 85 patients (64%)
• The 10-year PFS, and OS rates were 45%, and 71%, respectively. The multivariate
analysis suggested that PORT significantly improved LC (p < 0.001) and PFS (p <
0.001).
• The PFS benefit of PORT was maintained in the subgroup of GTR (p=0.001), WHO
grade II (p=0.001), or STR (p < 0.001). In the favorable subgroup of GTR and WHO
grade II, PORT was also significantly related to better PFS (p=0.028). WHO grade
III was significantly associated with poor DMFS (p=0.029).
• In the PORT subgroup, the 0–0.5 cm margin of the target volume showed an
inferior LC to a large margin with 1.0–2.0 cm (p=0.021). Time-dependent Cox
proportion analysis showed that distant failures were significantly associated with
poor OS (p=0.003).

12. Extrameningeal solitary fibrous tumors—surgery alone or
surgery plus perioperative radiotherapy: A retrospective study
from the global solitary fibrous tumor initiative in collaboration
with the Sarcoma Patients EuroNet
• Of all 549 patients, 428 (78%) underwent S, and 121 (22%)
underwent S+RT. The median follow-up was 52 months. After
correction for mitotic count and surgical margins, S+RT was
significantly associated with a lower risk of local progression (hazard
ratio, 0.19: P = .029), an observation further confirmed by propensity
score matching (P = .012); however, this association did not translate
into an overall survival benefit.

13. Chemotherapy
• Chemotherapy has typically been used in the advanced or metastatic
setting of SFT patients. However, very limited prospective evidence on
the activity of standard cytotoxic drugs is available in SFT

15. • While the prognosis is usually excellent for most SFT without
malignant histologic features, in view of the unpredictable nature of
this disease, long-term follow-up is mandatory.
• SFT with malignant features are predictive of poorer outcomes with
overall median survival ranging from 59 to 94 months.
• Tumor size (>10 cm) and high mitotic rates have been reported as
predictive of a higher incidence of metastatic disease.
• Common metastatic sites include the lungs, bones, and liver.

16. Thank you