Single-Fraction Stereotactic Radiosurgery for Residual, Recurrent, or Metastatic Intracranial Solitary Fibrous Tumors: An IRRF Study Toward Management Guidance.

The aim of this study was to evaluate safety and survival following hepatic artery embolization (HAE) for metastatic solitary fibrous tumor (SFT) in the liver. All patients with SFT metastatic to liver treated with HAE were retrospectively analyzed. Tumor response was evaluated using mRECIST. Objective response, overall survival (OS), and progression-free survival (PFS) were evaluated using Kaplan–Meier and multivariate Cox proportional hazard ratio. Adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. Twelve patients (6 males and 6 females, mean age: 42.5 ± 13 years; 24–65) were treated with 33 embolizations. Anatomical sites of origin for SFT were the head and neck (n = 6; 50%), pelvis (n = 2), pleura (n = 2), retroperitoneal (n = 1), and thigh (n = 1). The median follow-up from first HAE was 4.5 years (3–7.9). 84% of the patients showed objective response [42% complete response (CR) plus 42% partial response (PR)] to HAE by mRECIST (95% CI, 60–99%). Patients with CR to HAE had significantly higher OS compared to others (p < 0.02). The postembolization median OS was 4 years (95% CI, 2.3–5.2), and mean PFS, for intra- or extrahepatic progression of disease, was 6 months (95%, CI, 3.2–7.1). One patient developed pneumonia/sepsis and died 27 days postembolization, possibly not directly related to embolization. No grade III or IV adverse events were identified in the remaining patients. In conclusion, HAE for metastatic liver SFT is a relatively safe treatment option with high response rate and should be considered as a treatment option for metastatic liver SFT. In our cohort of patients with metastatic SFT to the liver, we observed a median OS of 4 years following HAE. Further studies are needed to confirm the efficacy of HAE.

The purpose of this critical review is to summarize the literature specific to single-fraction stereotactic radiosurgery (SRS) and multiple-fraction stereotactic radiation therapy (SRT) for postoperative brain metastases resection cavities and to present practice recommendations on behalf of the ISRS. The Medline and Embase databases were used to apply the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach to search for manuscripts reporting SRS/SRT outcomes for postoperative brain metastases tumor bed resection cavities with a search end date of July 20, 2018. Prospective studies, consensus guidelines, and retrospective series that included exclusively postoperative brain metastases and had at minimum 100 patients were considered eligible. The Embase search revealed 157 manuscripts, of which 77 were selected for full-text screening. PubMed yielded 55 manuscripts, of which 23 were selected for full text screening. We deemed 8 retrospective series, 1 phase 2 prospective study, 3 randomized controlled trials, and 1 consensus contouring paper appropriate for inclusion. The data suggest that SRS/SRT to surgical cavities with prescription doses of 30 to 50 Gy equivalent effective dose (EQD) 210, 50 to 70 Gy EQD25, and 70 to 90 EQD22 are associated with rates of local control ranging from 60.5% to 91% (median, 80.5%). Randomized data suggest improved local control with single-fraction SRS compared with observation and improved cognitive outcomes compared with whole-brain radiation therapy (WBRT). The toxicity of SRS/SRT in the postoperative setting was limited and is reviewed herein. Although randomized data raise concern for poorer local control after resection cavity SRS than WBRT, these findings may be driven by factors such as conservative prescription doses used in the SRS arm. Retrospective studies suggest high rates of local control after single-fraction SRS and hypofractionated SRT for postoperative brain metastases. With a superior neurocognitive profile and no survival disadvantage to withholding WBRT, the ISRS recommends SRS as first-line treatment for eligible postoperative patients. Emerging data suggest that fractionated SRT may provide superior local control compared with single-fraction SRS, in particular, for large tumor cavity volumes/diameters and potentially for patients with a preoperative diameter greater than 2.5 cm.

Single-Fraction Stereotactic Radiosurgery (SRS) Alone Versus Surgical Resection and SRS for Large Brain Metastases: A Multi-institutional Analysis

Patients with locally advanced, recurrent or metastatic solitary fibrous tumour are often treated with bevacizumab and temozolomide based on the clinical efficacy reported in a case series of 14 patients. Given the rarity of solitary fibrous tumour, large trials are not feasible. We report the efficacy of this regimen based on a population-based analysis. This was a population-based retrospective, multi-centre analysis using patient data from a provincial cancer registry and treatment database. Cases from June 2006 through October 2016 were identified for patients receiving bevacizumab and temozolomide for locally advanced, recurrent or metastatic solitary fibrous tumour or hemangiopericytoma, which is sometimes used to describe tumours arising from the meninges. The primary outcome was overall response rate. Secondary outcomes included time to response, progression free survival and overall survival estimated using the Kaplan-Meier method. Fourteen patients were identified: median age 59 (range 44-70), male 78.6%. Diagnoses were solitary fibrous tumour in 10 (71.4%) and hemangiopericytoma in four (28.6%), with metastatic disease in 10 (72.7%) patients. The most common primary sites were meninges in four (28.6%) and pelvis in three (21.4%) patients. The median follow-up was 15.5 months, with median treatment of four months. Overall response rate was 21.4% (no complete response, 3 partial response), with median time to response of four months. Median progression free survival, six-month progression free survival and overall survival were 17 months, 65.0%, and 45 months, respectively. Efficacy of bevacizumab and temozolomide in solitary fibrous tumour appeared to be similar to that previously reported. Our findings confirmed that bevacizumab and temozolomide is an effective and tolerated treatment for this patient population.

e22535 Background: Patients with locally advanced, recurrent or metastatic HPC/SFT are often treated with a combination of BEV/TEM based on the clinical efficacy reported in a cases series of 14 patients (Park MS, et al. Cancer 2011). BEV is costly and this regimen should ideally be supported with further data. Given the rarity of HPC/SFT, large trials are not feasible. We report the efficacy of this regimen based on population-based analysis. Methods: This was a population-based retrospective, multi-centre analysis using patient data from the BC Cancer Agency, a government funded, integrated care organization which delivers cancer drug therapy through a network of cancer centres in the province of British Columbia, Canada. Cases from June 2006 through October 2016 were identified from the provincial registry and systemic therapy drug database for patients receiving at least one treatment of BEV/TEM for histologically diagnosed locally advanced, recurrent or metastatic HPC/SFT. The primary outcome was overall response rate (ORR) based on changes of lesion size in computerized tomography scan and clinical assessment through chart review. Secondary outcomes included time to response, progression free survival (PFS) and overall survival (OS), estimated using the Kaplan-Meir method. Results: Fourteen patients were identified: median age 59 (range 44-70), male 78.6%. Diagnoses were HPC 4 (28.6%) and SFT 10 (71.4%), with metastatic disease in 10 (72.7%) patients. Primary sites were: meninges 4 (28.6%), lung/pleura 2 (14.3%), pelvis 3 (21.4%), abdominal wall 2 (14.3%), gluteal regional 1 (7.1%), others 2 (14.3%). Eleven (78.6%) patients had no prior drug therapy. The median follow-up was 15.5 months, with median treatment of 4 months. ORR was 21.4% with median time to response of 4 months (3 [21.4%] partial response, 10 [71.4%] stable disease, 1 [7.1%] progressive disease). Median PFS, 6-month PFS and OS were 17 months, 65.0%, and 45 months, respectively. Conclusions: Efficacy of BEV/TEM in HPC/SFT appeared to be similar to that previously reported. PFS and OS were longer in our patients, probably reflected by having most patients with SFT and less heavily pretreated.

Single Fraction Stereotactic Radiosurgery of Meningeal Hemangiopericytomas

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.

Background Stereotactic radiosurgery (SRS) is preferred to whole brain radiotherapy (WBRT) for the treatment of patients with a limited number of brain metastases, both as primary treatment and after surgery. SRS can be delivered in a single fraction (SF) or in multiple fractions (MF) depending on tumor size and location. The aim of this single-center retrospective study was to evaluate intracranial control and overall survival (OS) in patients who received SF and MF SRS for brain metastases. Material and Methods All patients treated with primary SRS for brain metastases at Aarhus University Hospital between 2015 and 2020 were identified. Independent of undergoing surgery, SF SRS (20 Gy) was administered for targets (gross tumor volume) &amp;lt;2 cm in diameter and MF SRS (24-27 Gy in 3 fractions) for targets &amp;gt;2 cm. SRS was not combined with WBRT. Treatment response was evaluated by 3-monthly MRI-scan. To evaluate intracranial control, first events were scored as local-only failure (tumor progression at the SRS treatment site), distant failure (tumor progression not at the SRS site), and combined failure (local and distant failure). Actuarial incidence of local failure (local-only and combined) and OS were estimated using the Kaplan-Meier method. To analyze the association of SF and MF SRS with local failure and OS, multivariable Cox regression analyses were used. Results The consecutive cohort consisted of 196 patients treated for 275 brain metastases. The most frequent primary disease was non-small cell lung cancer (NSCLC n=96), followed by renal cell carcinoma (n=26) and breast cancer (n=22). SRS was delivered to 1 (n=133), 2 (n=49), 3 (n=12), and 4 (n=2) targets per patient. SF and MF SRS was used in 99 (51%) and 97 (49%) patients, respectively. In 40 patients, SRS was administered after surgery (SF n=7, MF n=33). At a median (range) follow-up of 10 (0-93) months, 111 (57%) patients had intracranial progression, and 159 (81%) patients died. Local-only/distant/combined failure rate was 23 and 42%/59 and 35%/18 and 23%, in SF and MF SRS respectively. The median time to local failure was respective 9.0 (95% CI 5.4-12.6) and 6.0 (95% CI 5.0-7.0) months in the SF and MF SRS group. SF SRS and surgery were independently associated with a longer time to local failure. Salvage WBRT, SRS, and re-operation were performed in respective 36, 13, and 26 patients. Histopathological radiation necrosis was observed in 5 patients. All patients with necrosis had a primary diagnosis of NSCLC, and 4/5 patients were treated with SF SRS. For the total group, the median OS was 10.0 (95% CI 8.0 - 12.0) months. PS&amp;lt;2, surgery, stable extracranial disease and SF SRS were associated with a longer survival. Conclusion MF SRS was associated with a higher rate of and shorter time to local failure, and was a poor prognostic factor for survival, which is in line with the selection of patients with more unfavorable brain metastases for this treatment.

Meningeal hemangiopericytomas (M-HPC) are challenging tumors with a high rate of recurrence despite surgical resection and external beam radiotherapy (EBRT). To better understand the role of single-fraction stereotactic radiosurgery (SRS) for patients with M-HPC, we reviewed our experience with 22 patients (12 men, 10 women) from 1990 until 2010. Twelve patients (55%) underwent a single SRS procedure, whereas 10 patients (45%) had more than one SRS procedure (range 2-6). In total, 47 SRS procedures were performed to treat 64 tumors. Fourteen patients (64%) had undergone prior EBRT (median dose, 56.0 Gy). Follow-up after the initial SRS (median, 66 months) was censored at the time of death (n = 15) or last clinical evaluation (n = 7). Eleven patients (50 %) died of intracranial tumor progression (n = 10) or treatment-related complications (n = 1). One patient (5%) died of systemic disease progression. Disease-specific survival (DSS) at 1-, 3- and 5-years after SRS was 96, 82, and 61%, respectively. Prior EBRT (HR 9.0, 95% CI 1.1-78.1, p < 0.05) and larger initial tumor volume (HR 1.09, 95% CI 1.02-1.2, p = 0.02) were associated with worse DSS. Local tumor control (LTC) after SRS at 1-, 3-, and 5-years was 89, 68, and 59%, respectively. Improved LTC was noted in patients who had not undergone prior EBRT (HR 6.3, 95% CI 2.1-19.5, p = 0.001). One patient (5%) had symptomatic radiation-relation complications after SRS. Overall, single-fraction SRS was effective in providing LTC for more than half of recurrent or residual M-HPC at 5-years after the procedure. Repeat SRS is often required secondary to either distant or local tumor progression.

Late recurrence of renal solitary fibrous tumour in the contralateral kidney

The efficacy of postoperative radiotherapy (PORT) after gross total resection (GTR) for intracranial solitary fibrous tumors (SFT) remains unclear due to the inconsistent results of previous studies, with some studies suggesting improved outcomes in progression-free survival (PFS) and overall survival (OS), while others report no significant benefit. Therefore, by evaluating and synthesizing data from relevant studies, we aimed to investigate the role of PORT, as compared with surgery alone, in survival outcomes after GTR of intracranial SFT. A systematic literature search, adhering to PRISMA guidelines and using Medline, Embase, and the Cochrane Library to identify relevant literature. The outcomes of interest included progression-free survival (PFS), overall survival (OS), and metastasis-free survival (MFS) at 3, 5, and 10 years, respectively. Differences between the two cohorts (GTR + PORT vs. GTR only) were estimated by calculating the hazard ratios. Twelve studies, including data from 419 patients (GTR + PORT, n = 225 vs. GTR, n = 194), were selected for meta-analysis. Pooled hazard ratios revealed that the PORT cohort showed sustained superiority in both PFS and OS compared with the surgery-only cohort after GTR of the tumor. These results were consistent with those of a subgroup analysis that focused on grade 2 and 3 intracranial SFT. However, no significant improvement was observed in MFS with PORT addition. This study underscores the importance of PORT in enhancing the PFS and OS of patients with intracranial SFT after GTR. These findings suggest that PORT should be considered an effective treatment strategy for all patients with intracranial SFT, irrespective of the extent of resection.

Postoperative Stereotactic Radiation Therapy for Patients With Resected Brain Metastases: Clinical Outcomes and Comparing the Efficacy of Single-Fraction Radiosurgery and Fractionated Stereotactic Radiation Therapy

The knowledge of optimal treatments for patients with intracranial solitary fibrous tumor (SFT) is limited, with inconclusive results from previous studies. In this study, we conducted a meta-analysis of relevant studies to identify the prognostic impact of the extent of resection (EOR) and postoperative radiotherapy (PORT) on survival outcomes of patients with intracranial SFT. We searched the Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) to identify relevant studies published till April 2022. Progression-free survival (PFS) and overall survival (OS) were the outcomes of interest. Differences between two cohorts (gross total resection [GTR] vs. subtotal resection [STR] and PORT vs. surgery only) were estimated by calculating hazard ratios. Twenty-seven studies were selected for the meta-analysis, including data of 1348 patients (GTR, n = 819 vs. STR, n = 381 and PORT, n = 723 vs. surgery only, n = 578). Pooled hazard ratios of PFS (1, 3, 5, and 10years) and OS (3, 5, and 10years) revealed that the GTR cohort showed sustained superiority over the STR cohort. In addition, the PORT cohort was superior to the surgery-only cohort with respect to all PFS periods. Although the 10-year OS between the two cohorts was not statistically different, PORT showed significantly better 3- and 5-year OS than surgery only. The study findings suggest that GTR and PORT provide significant benefits for PFS and OS. Aggressive surgical resection of tumors to achieve GTR followed by PORT should be implemented as optimal treatments for all patients with intracranial SFT when feasible.

Objective: To investigate the efficacy and safety of pazopanib for recurrent or metastatic solitary fibrous tumor (SFT) in first- and second-line settings. Methods: Patients histologically diagnosed with SFT at our hospital who received pazopanib monotherapy for inoperable disease between January 2013 and November 2016 were eligible. We retrospectively investigated treatment outcomes according to the treatment lines and assessed adverse events. Results: Nine patients were eligible. The median age was 67 years (range 42–81), and 6 patients (66.7%) were male. Four patients (50%) received pazopanib as second-line treatment. According to the RECIST and Choi criteria, the respective response rates were 0 and 50%, while the respective disease control rates were 88.9 and 75%. The median progression-free survival (PFS) was 6.2 months (95% confidence interval 3.2–8.8). Treatment line and high frequency of mitosis were not predictive of PFS (p = 0.67, 0.92). Two patients (22.2%) experienced elevated liver enzymes of grade 3 or higher. Conclusion: Pazopanib is an effective treatment option for recurrent or metastatic SFT in first- and second-line settings. Liver injury is a major adverse event and adequate treatment withdrawal and dose reduction should be considered when necessary.

BACKGROUND The efficacy of postoperative radiotherapy (PORT) after gross total resection (GTR) for intracranial solitary fibrous tumors (SFT) remains unclear as previous studies yielded inconsistent results. Therefore, this study aimed to clarify this uncertainty using a comprehensive meta-analysis. By evaluating and synthesizing data from relevant studies, we sought to investigate the role of PORT, as compared with surgery alone, in survival outcomes after GTR of intracranial SFT. METHODS We conducted a systematic literature search, adhering to PRISMA guidelines, using Medline, Embase, and the Cochrane Library to identify relevant literature. The outcomes of interest included progression-free survival (PFS), overall survival (OS), and metastasis-free survival (MFS) at 3, 5, and 10 years, respectively. Differences between the two cohorts (GTR+PORT vs. GTR only) were estimated by calculating the hazard ratios. Results. Twelve studies, including data from 419 patients (PORT, n = 225 vs. surgery only, n = 194), were selected for meta-analysis. Pooled hazard ratios revealed that the PORT cohort showed sustained superiority in both PFS and OS over the surgery-only cohort after GTR of the tumor. These results were consistent with those of a subgroup analysis that focused on grade 2 and 3 intracranial SFT. However, no significant improvement was observed in MFS with PORT addition. Conclusion. The present study underscores the importance of PORT in enhancing the PFS and OS of patients with intracranial SFT after GTR. These findings suggest that PORT should be considered an effective treatment strategy for all patients with intracranial SFT, irrespective of the extent of resection.