Prognostic Factors of Survival for Grade 3 Solitary Fibrous Tumor/Hemangiopericytoma: A Population-Based Retrospective Surveillance, Epidemiology, and End Results Database Analysis.

INTRODUCTION: Grade 3 solitary fibrous tumor, previously known as anaplastic hemangiopericytoma, is a rare and highly malignant intracranial tumor with a limited understanding of its natural history and treatment outcomes. METHODS: We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database spanning 2000-2019 to evaluate the clinical characteristics and treatment modalities that influence overall survival in this tumor entity. A cohort of 249 patients with intracranial grade 3 solitary fibrous tumors was identified. Univariate and multivariable Cox proportional hazard models were employed to determine significant prognostic factors for overall survival. Kaplan-Meier models were used to visualize survival curves, and a nomogram was constructed to predict survival probabilities at 6- and 12-month following diagnosis. RESULTS: Our findings indicated that patient age (<65 years), localized or regional disease burden, surgical resection, and radiation therapy were significant predictors of better overall survival. Combination therapies showed improved survival, with surgery and radiation therapy having the most significant impact. However, chemotherapy alone or in combination did not demonstrate a significant survival benefit, likely due to the limited sample size. The nomogram provided personalized prognostic predictions based on significant clinical factors. CONCLUSIONS: These data emphasize the importance of surgical resection and radiation therapy in the management of grade 3 solitary fibrous tumors, supporting the use of combination therapies to improve overall survival in this rare and aggressive intracranial neoplasm.

A review of solitary fibrous tumor/hemangiopericytoma tumor and a comparison of risk factors for recurrence, metastases, and death among patients with spinal and intracranial tumors.

Meningeal solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) had been combined into a single classification until 2016. Recurrence and metastases rates are still understudied, especially for spinal SFT/HPCs. Here, we describe CNS SFT/HPCs and predictors for recurrence, metastases, and death, in spinal and intracranial SFT/HPCs, separately. We collected data from studies with patient-level data available on primary SFT/HPCs from multiple online databases. Clinico-demographic data, surgical outcomes, recurrence, metastases, and death rates were abstracted. We used logistic and Cox regression models to identify predictors for recurrence, metastases, and death for spinal and intracranial SFT/HPCs. Twenty-nine studies (368 patients) were included. Higher histological grade and subtotal resection were associated with recurrence (p values < 0.05), while higher histological grade and recurrence (p values < 0.005) were associated with metastases formation. Time to recurrence (p < 0.005) and metastases (p < 0.001) formation were shorter for spinal SFT/HPCs. Death rates were higher among intracranial SFT/HPC patients (p value = 0.001). Among patients with higher histological grade, rates of metastases formation were different between intracranial and spinal SFT/HPCs. Risk of metastases was higher in the first 5 years from surgery for both intracranial and spinal SFT/HPCs. Meningeal SFT/HPCs patients have high rates of recurrence and metastasis, which occur mostly within the first 5 years after diagnosis. Spinal and intracranial SFT/HPCs show similar behavior, but spinal SFT/HPCs tend to develop metastases and recurrences in a shorter interval of time. Careful follow-up for spinal SFT/HPCs should be considered because spinal cases seem to be slightly more aggressive and require more attention.

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.

BACKGROUND: Solitary fibrous tumor (SFT) is a rare mesenchymal malignancy. Although surgery is potentially curative, the local relapse risk is high after marginal resections. Given the lack of prospective clinical trial data, the objective of the current study was to better define the role of perioperative radiotherapy (RT) in various SFT presentations by location. METHODS: This was retrospective study performed across 7 sarcoma centers. Clinical information was retrieved from all adult patients with extrameningeal, primary, localized SFT who were treated between 1990 and 2018 with surgery alone (S) compared with those who also received perioperative RT (S+RT). Differences in treatment characteristics between subgroups were tested using analysis of variance statistics and propensity score matching. Local control and overall survival rates were calculated from the start of treatment until progression or death from any cause. RESULTS: 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. CONCLUSIONS: The results from this retrospective study investigating perioperative RT in patients with primary extrameningeal SFT suggest that combining RT with surgery in the management of this patient population is significantly associated with a reduced risk of local failures, especially in patients who have less favorable resection margins and in those who have tumors with a high mitotic count.

Clinicopathological review of solitary fibrous tumors: dedifferentiation is a major cause of patient death.

Solitary fibrous tumor (SFT) is a soft-tissue neoplasm of intermediate malignant potential, presenting a wide histopathological spectrum. Poorer prognosis of hemangiopericytoma of the central nervous system (CNS), hypoglycemic SFT, and dedifferentiation are well-known characters of SFT, but their clinical significance were not demonstrated enough by large-sized study. Here, the clinicopathological features of SFTs are reviewed and the relationship between genetics and clinicopathological features is examined using 145 SFT cases. All cases were STAT6 IHC-positive and/or NAB2-STAT6 fusion gene-positive. Tumor location was classified into three categories: 30 pleuropulmonary, 96 non-pleuropulmonary/non-central nervous system (CNS), and 18 CNS tumors. The tumor developed recurrence in 21 of 93 available cases (22.5%), metastasis in 11 of 93 (11.8%), and tumor death in 9 of 93 (9.6%). Hypoglycemia occurred in 2 primary tumors and 1 metastatic tumor among 63 reviewable cases, and dedifferentiation occurred in 10 cases (6.8%) including 6 primary tumors, 2 recurrent tumors, and 2 metastatic tumors. Recurrence was positively associated with CNS location (p = 0.0109) and hypoglycemia (p = 0.001); metastasis was positively associated with CNS location (p = 0.0231), hypoglycemia (p < 0.0001), and dedifferentiation (p < 0.0001), while metastasis was negatively correlated with pleural location (p = 0.0471). Tumor death was positively associated with male sex (p = 0.0154), larger size (p = 0.0455), hypoglycemia (p < 0.0001), and dedifferentiation (p < 0.0001). Multivariate analysis revealed independent statistical significance of dedifferentiation for overall survival (p = 0.0467). Exon variant of the fusion gene had no statistical correlation with clinical outcome. In conclusion, dedifferentiation is a major prognostic factor of SFT, and specific location such as cerebromeningeal and intra-abdominal site and hypoglycemia also had a high risk for unfavorable prognosis.

Spinal location is prognostic of survival for solitary-fibrous tumor/hemangiopericytoma of the central nervous system.

BACKGROUND: Prior studies have highlighted infratentorial tumor location as a prognostic factor for solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) of the central nervous system (CNS), and spinal location is considered a positive prognostic factor for other tumors of the CNS. While SFT/HPC of the CNS is known to frequently arise from the spinal meninges, there are no case series that report outcomes for spinally located CNS tumors, and their prognosis in relation to intracranial and other CNS-located tumors is unknown. OBJECTIVE: To investigate outcomes for patients with SFT/HPC of the spinal meninges. METHODS: The Surveillance, Epidemiology, and End-Results Program was used to identify patients with SFT/HPC within the CNS from 1993-2015. We retrospectively analyzed the relationship between tumor location (spinal vs. Brain and other CNS) and survival. RESULTS: We identified 551 cases of CNS SFT/HPC, 64 (11.6%) of which were primary tumors of the spinal meninges. Spinal tumors were more likely than brain and other CNS tumors to be SFT vs. HPC (37.5 vs. 12%, p < 0.001), benign (42.2 vs. 20.3%, p < 0.001), and less than 5 cm (53.1 vs. 35.7%, p < 0.001). The 10-year survival rates for spinal and brain/other CNS tumors were 85 and 58%, respectively. Median survival time was significantly longer for spinal tumors (median survival not reached vs. 138 months, p = 0.03, HR = 0.41 [95% CI 0.18-0.94]). On multivariable analysis, spinal tumor location was associated with improved survival over tumors located in the brain and other CNS (HR = 0.36 [95% CI 0.15-0.89], p = 0.03). CONCLUSION: Spinal tumor location is associated with improved survival in patients with SFT/HPC of the CNS. Larger institutional studies are necessary to characterize the relationship between tumor location and other relevant factors such as presentation and amenability to gross-total resection and adjuvant radiotherapy. Future studies exploring optimal management of spinally located tumors are also needed.

Activity of axitinib in progressive advanced solitary fibrous tumour: Results from an exploratory, investigator-driven phase 2 clinical study.

BACKGROUND: To explore the activity of axitinib in advanced solitary fibrous tumour (SFT). PATIENTS AND METHODS: In this investigator-driven phase II study on axitinib in advanced and progressive SFT, patients received axitinib, 5 mg bis in day (BID), until progression or limiting toxicity. Pathologic diagnosis was centrally reviewed, distinguishing malignant SFT (M-SFT) and high-grade/dedifferentiated SFT (HG/D-SFT) subtypes. The primary end-point was the overall response rate (ORR) by Choi criteria (Choi). Secondary end-points were response by Response Evaluation Criteria in Solid Tumours (RECIST), progression-free survival (PFS) and overall survival (OS). RESULTS: From April 2015 and October 2017, 17 eligible patients entered the study (metastatic: 17; SFT subtype: 13 M-SFT, 4 HG/D-SFT; prior treatment: 9 antiangiogenics, 5 cytotoxics). All patients were evaluable for response. The best Choi response was seven partial response (PR) (ORR, 41.2%), six stable disease (SD) and four progressions. Choi-ORR was 54% (7/13) when only M-SFTs were considered. Four of seven responsive patients were pretreated with pazopanib. No responses were detected in HG/D-SFT. Best RECIST response was one PR (5.9%), 14 SD and two progressions. Toxicity was as expected. Median Choi-PFS was 5.1 (interquartile range [IQR]: 2.5-14.8) months. Median Choi-PFS was 14.8 (IQR: 5.1-18.0) and 2.8 (IQR: 2.0-5.9) months for patients responsive and non-responsive by Choi, respectively (p = 0.0416). At a 14.4-month median follow-up, median OS was 25.3 months. CONCLUSION: This study showed that axitinib is active in progressive advanced SFT. One-half of patients carrying the malignant variant of the disease responded, with a >12-month median progression arrest. Responses were better detected with Choi and seen even in patients resistant to other antiangiogenics. Tolerability was good.

Solitary Fibrous Tumor/Hemangiopericytoma of Spinal Cord: A Retrospective Single-Center Study of 16 Cases.

OBJECTIVE: In this study, we retrospectively reviewed our experience in the surgical management of solitary fibrous tumor (SFT)/hemangiopericytomas (HPCs) of the spinal cord. METHODS: Sixteen patients with SFT/HPCs of the spinal cord were enrolled in this study. Data on clinical presentation, radiologic findings, histopathologic features, surgical treatment, adjuvant therapy, and prognosis were retrospectively reviewed. Kaplan-Meier curves and log-rank tests were used to identify the prognostic factors for recurrence and overall survival (OS). RESULTS: Our series included 6 men and 10 women, with a male/female ratio of 1:1.7. Magnetic resonance imaging (MRI) showed slightly hyperintense lesions on T2-weighted images for all 16 patients. All tumors showed positive immunohistochemical staining for signal transducer and activator of transcription 6. Statistical analysis of clinical data showed that age, gender, tumor location, tumor size, medullary compartment location, and Ki-67 index were not associated with recurrence and OS (P > 0.05). However, World Health Organization grade III was significantly associated with recurrence (P < 0.01). Gross total resection (GTR) and postoperative radiotherapy significantly reduced recurrence (P < 0.01 and P < 0.05), but only GTR showed remarkable benefits to improve OS (P < 0.05). CONCLUSIONS: SFT/HPCs of spinal cord are rare neoplasms with a propensity to recur. Hyperintensity on T2-weighted magnetic resonance imaging combined with positive immunohistochemical staining for signal transducer and activator of transcription 6 are important clues for classification and differentiation of these tumors. The extent of resection, World Health Organization grade, and postoperative radiotherapy might be predictive factors for recurrence. Complete tumor resection should be sought whenever possible, and adjuvant radiotherapy is recommended after surgical resection. Moreover, regular and long-term follow-up is mandatory to monitor recurrence.

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.

PURPOSE: Solitary fibrous tumors (SFTs) are extremely rare mesenchymal malignancies. Given the lack of large prospective studies on radiation therapy (RT) with definitive and/or palliative intent in SFT patients, this retrospective study aimed to better define the benefit of RT in this disease. METHODS AND MATERIALS: A retrospective observational study was performed across 7 sarcoma centers. Clinical information was retrieved from all patients receiving RT without surgery over the course of their locally advanced and/or metastatic disease. Differences in treatment characteristics between subgroups were tested using analysis-of-variance tests. Local control (LC) and overall survival (OS) rates were calculated as time from the start of RT until local progression and death from any cause, respectively. RESULTS: Since 1990, a total of 40 patients were identified. RT was applied with definitive intent in 16 patients and with palliative intent in 24. The median follow-up period was 62 months. In patients treated with definitive RT (receiving approximately 60 Gy), the objective response rate was 67%. At 5 years, the LC rate was 81.3%, and the OS rate was 87.5%. In the case of palliative RT (typically 39 Gy), the objective response rate was 38%. The LC and OS rates at 5 years were 62.5% and 54.2%, respectively. In both subgroups, RT-associated toxicities were mild with predominantly grade 1 acute and late side effects. CONCLUSIONS: This retrospective study suggests a clinically meaningful benefit for RT given with either definitive or palliative intent without surgery in SFT management. Prospective registries potentially in collaboration with patient advocacy groups are warranted to further assess the role of RT in patients with this rare malignancy.

The Approach to Solitary Fibrous Tumors: Are Clinicopathological Features and Nomograms Accurate in the Prediction of Prognosis?

INTRODUCTION: Currently, factors such as size, mitotic rate, and degree of necrosis have been shown to influence survival in patients with solitary fibrous tumors (SFTs); however, there remains no consensus regarding the associations between tumor characteristics and the malignant nature of these tumors. The aim of this article was to identify factors that would help in prognosticating SFTs and to validate the MD Anderson Cancer Center (MDACC) SFT nomogram in the largest known series of SFTs treated in an Asian population. METHODS: A retrospective review of all patients with a diagnosis of SFT treated surgically in our institution between 2005 and 2015 was carried out. Basic demographics, clinicopathological, and surgical factors were analyzed for association with clinical outcomes. Factors that predicted for distant recurrence (DR) and poor survival were identified as high-risk features. The MDACC nomogram was validated by assessing the extent of discrimination, quantified using Harrell's concordance index (C-index). RESULTS: Fifty-nine patients were included in analysis. Significant univariate associations for DR were found for mitotic rate ( P = .05) and presence of necrosis ( P = .04). Significant univariate associations for overall survival were found for presence of recurrence ( P = .035), presence of necrosis ( P = .072), and mitotic rate ( P = .033). The C-index associated with the nomogram was 0.75. CONCLUSION: There is a negative association for DR and overall survival, with the mitotic rate and presence of necrosis. We propose that SFTs with these features should be regarded as high risk. The MDACC nomogram generally predicts well for patients in an Asian population.

Association between programmed cell death ligand-1 expression and extracranial metastasis in intracranial solitary fibrous tumor/hemangiopericytoma.

BACKGROUND: Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) often shows extracranial metastasis, and treatment options are very limited. Immune-checkpoint molecules have not been studied well in SFT/HPCs, and their role in intracranial SFT/HPCs remains unclear. METHODS: We investigated the expression of programmed cell death-1 (PD-1), programmed cell death ligand-1 (PD-L1), and tumor-infiltrating lymphocytes (TIL) in 16 patients of intracranial SFT/HPC by immunohistochemistry to determine if correlation with prognosis exists. RESULTS: Median overall survival (OS) of 16 patients was 9.2 years, and median follow-up of alive patients was 9.9 years. Recurrence was observed in 13 (81.3%) patients, and extracranial metastasis were observed in 6 (37.5%). PD-L1 expression was observed in all 16 tumors, whereas PD-1 expression was observed in 2. CD3 and CD8 expressions were observed in TILs in 12 and 13 patients respectively. Although the ratio of PD-L1 positive-tumor cells was not associated with OS, progression-free survival, or metastasis-free survival (MFS), diffuse staining of PD-L1 showed a trend toward shorter time to treatment failure (TTF: time to either extracranial metastasis or death) (p = 0.072). Similarly, the intense staining of PD-L1 was associated with shorter MFS (p = 0.0084) and TTF (p = 0.033). CD3 or CD8 expression was not associated with any of the prognostic parameters. In the combined analysis of PD-L1 and CD8, diffuse PD-L1 staining coupled with no or sparse CD8 expression was significantly associated with a shorter TTF (p = 0.005) and showed a trend toward shorter MFS (p = 0.0611). CONCLUSIONS: PD-L1 is frequently expressed in intracranial SFT/HPCs, and diffuse or intense PD-L1 expression might be associated with the early occurrence of extracranial metastases.

Tumor fibroso solitario cutáneo: una neoplasia fusocelular con una inmunohistoquímica particular / Cutaneous Solitary Fibrous Tumor: A Spindle Cell Neoplasm With Distinctive Immunohistochemical Features

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Solitary fibrous tumours and haemangiopericytoma of the meninges. A retrospective study for outcome and prognostic factor assessment.

BACKGROUND: To report on the outcome of patients diagnosed with central nervous system haemangiopericytoma (HPC) or solitary fibrous tumours (SFT) and identify factors that may influence recurrence and survival. MATERIAL AND METHODS: Between January 1977 and December 2016, a retrospective search identified 22 HPCs/SFTs. The patients underwent a total of 40 surgical resections and 63.6% received radiotherapy. Median follow-up was 7.8 years. RESULTS: Six patients (27.3%) were re-operated for tumour recurrence. At the end of the study, 15 patients (68.2%) had no residual tumour on the last imaging. Surgical recurrence-free survival at 5 years was 77.4%, [95% CI: 60.1-99.8]. None of the investigated variables was associated with recurrence. At the end of the study, 5 patients were deceased (22.7%) and only 10 patients (45.5%) had no residual tumour on the last imaging and were alive. Overall survival at 5 years was 95%, [95% CI: 85.9-100]. None of the investigated variables was associated with overall survival. Patients who received radiotherapy demonstrated neither a reduced risk of surgical recurrence (P=0.378) nor a longer overall survival (P=0.405). CONCLUSION: SFTs/HPCs are associated with a significant risk of recurrence that may reduce the survival. Even if we could not demonstrate their benefit in this limited series, we believe that tailored maximal tumour resection on initial surgery is beneficial and that adjuvant RT is useful for tumours displaying grade II or III, even in case of complete removal.

Soft Tissue Solitary Fibrous Tumor: Combined Surgery and Radiation Therapy Results in Excellent Local Control.

PURPOSE: To report survival outcomes and local control in patients with solitary fibrous tumors (SFT) treated using surgery and radiation therapy (RT). METHODS: We reviewed the medical records of 31 consecutive patients definitively treated for SFT with surgery and RT between 1982 and 2012. The median age was 51 years (range, 23 to 88 y) and tumors were evenly distributed between the head and neck (n=9, 29%), trunk (n=10, 32%), and lower extremities (n=9, 29%). The majority of tumors were large (>5 cm) (n=23, 72%). Specimens had a median of 2 mitoses/10 HPF (range, 0 to 8). Nearly half the cases were treated with postoperative RT (n=14, 45%; median dose, 58 Gy) and the other 17 patients (55%) received preoperative RT (median dose, 50 Gy). RESULTS: Median follow-up time was 59 months (range, 18 to 349 mo). The 5-year rates of local control, overall survival, and distant metastatic-free survival were 100%, 95%, and 92%, respectively. There were no local or nodal relapses and the 10-year complication rate was 6% (n=2). CONCLUSIONS: Treatment of soft tissue SFT using combined surgery and RT results in excellent local control.

Surgical management of spinal solitary fibrous tumor/hemangiopericytoma: a case series of 20 patients.

PURPOSE: Spinal solitary fibrous tumor/hemangiopericytoma (SFT/HPC), a rare mesenchymal tumor that arises from pericytes of Zimmerman, comprises only 0.08% of all primary bone tumors and 0.1% of primary malignant bone tumor and rarely occurs in the spine. We attempt to correlate the clinical factors and different treatment options with the recurrence rate and overall survival of SFT/HPC over time. METHODS: A retrospective study of 20 patients with spinal osseous SFT/HPCs who were surgically treated in our center between 2003 and 2015 was performed. Kaplan-Meier curves and log-rank tests were used to compare the survival probability or recurrence-free probability between groups, and P values < 0.05 were considered statistically significant. RESULTS: Three surgical management strategies, including subtotal resection, piecemeal total resection, and total en bloc spondylectomy (TES) were applied. Postoperative radiotherapy was carried out in 14 cases. The mean follow-up period was 38.3 (median 35, range 7-93) months, and 6 patients passed away with the mean follow-up time of 47.7 (median 41, range 24-77) months. Relapse was detected in 9 patients (45%) with the mean time from surgery to recurrence being 36.6 (median 28, range 12-73) months. Our results indicate that grade III is an adverse prognostic factor for both recurrence and over survival (OS) for spinal osseous SFT/HPC, while total resection, especially TES, is a positive prognostic factor. CONCLUSIONS: Spinal osseous SFT/HPC is a challenging clinical entity given its high local recurrence rate. Surgical management plays a crucial role in the whole treatment of spinal SFT/HPCs and total excision, especially TES, should be strived for whenever possible. Postoperative radiotherapy is recommended to lower the recurrent rate. This study also confirms that pathology grade III is an adverse prognostic factor for spinal osseous SFT/HPCs.

Solitary Fibrous Tumors of the Head and Neck: A Multi-Institutional Clinicopathologic Study.

Solitary fibrous tumors (SFTs) of the head and neck are uncommon. Lesions previously diagnosed in the head and neck as hemangiopericytomas (HPCs), giant cell angiofibromas (GCAs), and orbital fibrous histiocytomas (OFHs) are now recognized as within the expanded spectrum of SFTs. To better understand the clinicopathologic profile of head and neck SFTs, we performed a multi-institutional study of 88 examples. There was no sex predilection (F:M ratio 1.2), and the median patient age was 52 years (range: 15 to above 89 y). The sinonasal tract and orbit were the most common sites involved (30% and 25%), followed by the oral cavity and salivary glands (15% and 14%). Original diagnoses included HPC (25%), SFT (67%), and OFH (6%), with 1 SFT and 1 OFH noted as showing GCA-like morphology. On review, the predominant histologic pattern was classic SFT-like in 53% and cellular (former HPC-like) in 47%; lipomatous differentiation (8%) and GCA-like pattern (7%) were less prevalent. Subsets demonstrated nuclear atypia (23%), epithelioid morphology (15%), or coagulative necrosis (6%). Infiltrative growth (49%) and osseous invasion (82%) were prevalent among evaluable cases. Of the 48 SFTs with follow-up (median: 43 mo), 19 showed recurrence (40%). Of these, 4 patients were alive with disease and 4 dead of disease. Size and mitotic rate were negative prognosticators using a joint prognostic proportional hazards regression model. Three patients experienced metastasis, to lungs, parotid, bone, and skull base, including one case showing overtly sarcomatous "dedifferentiation." As a group, SFTs present in a wide anatomic and morphologic spectrum in the head and neck. Only rare examples metastasize or cause death from disease. However, the fairly high local recurrence rate underscores their aggressive potential and highlights the importance of prospective recognition.

Risk assessment in solitary fibrous tumors: validation and refinement of a risk stratification model.

Solitary fibrous tumors are an uncommon sarcoma type characterized by NAB2-STAT6 gene fusion. While solitary fibrous tumors metastasize in 5-25% of cases, it has historically been challenging to determine which specific tumor and patient characteristics predict aggressive behavior. We previously reported on a novel risk stratification scheme for solitary fibrous tumors incorporating patient age, tumor size, and mitotic activity to predict risk of metastasis. Herein we validate this risk stratification scheme in an independent, lower-risk population of 79 patients with primary non-meningeal solitary fibrous tumors, and propose incorporating tumor necrosis as a fourth variable to further improve the risk score. Fifty-seven percent of cases were considered low risk, 29% intermediate risk, and 14% high risk for metastasis. Of 50 patients with sufficient clinical follow-up data, no metastases developed in the low-risk patients (n=23), while there was a 7% 10-year metastatic risk in the intermediate risk group (n=17), and a 49% 5-year metastatic risk for the high-risk patients (n=10). When tumor necrosis was added as a fourth variable to the model, predictive power was enhanced. Under the revised stratification, the proportion of tumors identified as low risk increased to 66%, with no metastasis at 10 years, intermediate risk cases comprised 24% with 10% risk of metastasis at 10 years, and high risk comprised 10% of cases with 73% risk of metastasis at 5 years. In Kaplan-Meier analysis, this fourth-variable stratification provided significant discrimination between the risk groups (P=0.0005). These findings confirmed the clinical utility of our previously published risk stratification model and support the inclusion of necrosis as a fourth variable in the model.

Patient-derived solitary fibrous tumour xenografts predict high sensitivity to doxorubicin/dacarbazine combination confirmed in the clinic and highlight the potential effectiveness of trabectedin or eribulin against this tumour.

BACKGROUND: Preclinical models that mimic pathological and molecular features of solitary fibrous tumour (SFT) represent an important tool to select effective regimes and novel compounds to be tested in the clinic. This study was aimed at developing two preclinical models of SFT, assessing their predictive value in the clinic and selecting potential novel effective treatments. MATERIAL AND METHODS: Two dedifferentiated-SFT (D-SFT) models obtained from patients' biopsies were grown in immunodeficient mice. The antitumour activity on these models of doxorubicin, dacarbazine (DTIC), ifosfamide (monotherapy or combination), trabectedin and eribulin was tested. Twelve SFT patients were treated with doxorubicin and DTIC. Response by RECIST, progression-free survival and overall survival were retrospectively evaluated, distinguishing malignant-SFT (M-SFT) and D-SFT. RESULTS: Two D-SFT patient-derived xenografts (PDXs) that represent the first available preclinical in vivo models of SFT were developed and characterised. Doxorubicin/DTIC, DTIC/ifosfamide, doxorubicin/ifosfamide combinations consistently induced better antitumour activity than the single-agents. Particularly, doxorubicin/DTIC combination caused a max tumour volume inhibition >80% in both models. Doxorubicin/DTIC combo showed activity also in the case-series. Best RECIST responses were: 6 responses (M-SFT = 2 of 7, D-SFT = 4 of 5), 1 stable disease, 5 progressions, with a 6-month median progression-free survival (M-SFT = 6, D-SFT = 10 months). The PDXs were very sensitive to trabectedin and eribulin. CONCLUSION: Doxorubicin plus DTIC combination was effective in our two D-SFT mice models and appeared to be active also in the clinic, especially in high-grade D-SFT patients. Among additional drugs tested in the PDXs, trabectedin and eribulin were highly effective, providing a rational to test these drugs in D-SFT patients.

Post-relapse outcomes after primary extended resection of retroperitoneal sarcoma: A report from the Trans-Atlantic RPS Working Group.

BACKGROUND: Despite a radical surgical approach to primary retroperitoneal sarcoma (RPS), many patients experience locoregional and/or distant recurrence. The objective of this study was to analyze post-relapse outcomes for patients with RPS who had initially undergone surgical resection of their primary tumor at a specialist center. METHODS: All consecutive patients who underwent macroscopically complete resection for primary RPS at 8 high volume centers from January 2002 to December 2011 were identified, and those who developed local recurrence (LR) only, distant metastasis (DM) only, or synchronous local recurrence and distant metastasis (LR+DM) during the follow-up period were included. Overall survival (OS) was calculated for all groups, as was the crude cumulative incidence of a second recurrence after the first LR. Multivariate analyses for OS were performed. RESULTS: In an initial series of 1007 patients with primary RPS, 408 patients developed recurrent disease during the follow-up period. The median follow-up from the time of recurrence was 41 months. The median OS was 33 months after LR (n = 219), 25 months after DM (n = 146), and 12 months after LR+DM (n = 43), and the 5-year OS rates were 29%, 20%, and 14%, respectively. Predictors of OS after LR were the time interval to LR and resection of LR, while histologic grade approached significance. For DM, significant predictors of OS were the time interval to DM and histologic subtype. The subgroup of patients who underwent resection of recurrent disease had a longer median OS than patients who did not undergo resection. CONCLUSIONS: Relapse of RPS portends high disease-specific mortality. Patients with locally recurrent or metastatic disease should be considered for resection. Cancer 2017;123:1971-1978. © 2017 American Cancer Society.

Analyses of prognosis-related factors of intracranial solitary fibrous tumors and hemangiopericytomas help understand the relationship between the two sorts of tumors.

Increasing evidence has suggested a close relationship between solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) in the central nervous system (CNS). However, CNS SFTs differentiate from HPCs in their clinical behavior and patient prognoses. Analyses of prognosis-related factors can help clarify the relationship between SFT and HPC. The intracranial SFT and HPC cases treated in our departments from January 2002 to December 2012 were retrospectively reviewed. The SFT and HPC cases were also combined into an SFT/HPC group. The factors associated with patient progression-free survival (PFS) and overall survival (OS) were statistically analyzed using uni- and multivariate analyses. Fifty-eight intracranial SFT/HPC patients including 38 SFT patients and 20 HPC patients were treated during this period. The "Marseille grading" evaluated upon the histological aggressive phenotypes was applied in this study. The grading reflected a malignant progression ranging from "conventional" SFTs (grade I) to WHO III HPCs (grade III), and grade was negatively correlated with the PFS and OS of the SFT, HPC and SFT/HPC patients (P < 0.05).The multivariate analyses revealed that gross total resection (GTR) was significantly positively correlated with PFS and OS in the SFT, HPC and SFT/HPC patients and that radiotherapy was significantly positively correlated with PFS in the HPC and SFT/HPC patients (P < 0.05). In conclusion, the intracranial SFTs and HPCs share common prognostic factors including extent of surgery and pathology, moreover, the histological grading of the aggressive phenotypes supports the unifying of the CNS SFT and HPC into one tumor entity of SFT/HPC.