Stereotactic radiosurgery for intracranial hemangiopericytomas: a multicenter study

Abstract

OBJECTIVE Hemangiopericytomas (HPCs) are rare tumors widely recognized for their aggressive clinical behavior, high recurrence rates, and distant and extracranial metastases even after a gross-total resection. The authors report a large multicenter study, through the International Gamma Knife Research Foundation (IGKRF), reviewing management and outcome following stereotactic radiosurgery (SRS) for recurrent or newly discovered HPCs. METHODS Eight centers participating in the IGKRF participated in this study. A total of 90 patients harboring 133 tumors were identified. Patients were included if they had a histologically diagnosed HPC managed with SRS during the period 1988-2014 and had a minimum of 6 months' clinical and radiological follow-up. A de-identified database was created. The patients' median age was 48.5 years (range 13-80 years). Prior treatments included embolization (n = 8), chemotherapy (n = 2), and fractionated radiotherapy (n = 34). The median tumor volume at the time of SRS was 4.9 cm (range 0.2-42.4 cm). WHO Grade II (typical) HPCs formed 78.9% of the cohort (n = 71). The median margin and maximum doses delivered were 15 Gy (range 2.8-24 Gy) and 32 Gy (range 8-51 Gy), respectively. The median clinical and radiographic follow-up periods were 59 months (range 6-190 months) and 59 months (range 6-183 months), respectively. Prognostic variables associated with local tumor control and post-SRS survival were evaluated using Cox univariate and multivariate analysis. Actuarial survival after SRS was analyzed using the Kaplan-Meier method. RESULTS Imaging studies performed at last follow-up demonstrated local tumor control in 55% of tumors and 62.2% of patients. New remote intracranial tumors were found in 27.8% of patients, and 24.4% of patients developed extracranial metastases. Adverse radiation effects were noted in 6.7% of patients. During the study period, 32.2% of the patients (n = 29) died. The actuarial overall survival was 91.5%, 82.1%, 73.9%, 56.7%, and 53.7% at 2, 4, 6, 8, and 10 years, respectively, after initial SRS. Local progression-free survival (PFS) was 81.7%, 66.3%, 54.5%, 37.2%, and 25.5% at 2, 4, 6, 8, and 10 years, respectively, after initial SRS. In our cohort, 32 patients underwent 48 repeat SRS procedures for 76 lesions. Review of these 76 treated tumors showed that 17 presented as an in-field recurrence and 59 were defined as an out-of-field recurrence. Margin dose greater than 16 Gy (p = 0.037) and tumor grade (p = 0.006) were shown to influence PFS. The development of extracranial metastases was shown to influence overall survival (p = 0.029) in terms of PFS; repeat (multiple) SRS showed additional benefit. CONCLUSIONS SRS provides a reasonable rate of local tumor control and a low risk of adverse effects. It also leads to neurological stability or improvement in the majority of patients. Long-term close clinical and imaging follow-up is necessary due to the high probability of local recurrence and distant metastases. Repeat SRS is often effective for treating new or recurre...

Treatment of orbital solitary fibrous tumour with gamma knife radiosurgery and systematic review of literature

“…The reviewed set of these series reported rates of tumour control ranging from 46% to 100%, and they included a range of 8–58 lesions studied. The recent study involved 90 patients with 133 tumours and reported a tumour control rate of 55% 20. However, while the evidence may roughly appear to distinguish the two as separate entities, we encounter the issue that previous studies and diagnoses were not attuned to the pathological spectrum.…”

Radiotherapy of Parasellar Tumours

“…Infiltrative aggressive tumours are typically treated with fractionated RT up to doses of 50-60 Gy, whereas SRS is usually employed for small-to-moderate benign lesions or in the setting of recurrent tumours. A summary of recent selected studies of fractionated RT and SRS for these rare parasellar tumours is shown in Table 5 [122][123][124][125][126][127][128][129].…”

Nervous System Hemangiopericytoma

“…9 Intracranial cavity involvement is rare in HPC, constituting approximately 0.4% of all intracranial lesions and 2.4% of meningeal lesions. 3,7,10,11 The first report of an intracranial HPC can be dated to 1954, by Begg and Garret, 12 but these were classified as a distinct pathological entity by the World Health Organization (WHO) only in 1993, based on clinical, immunohistochemical, ultrastructural, and genetic features. [13][14][15] The 2016 WHO classification defines the solitary fibrous tumors (SFTs)-HPC entities on a single spectrum with a single grading system.…”

“…The cumulative risk of ENM reaches as high as 70% in 15 years. [2][3][4]6,10,[21][22][23][24][25][26] The incidence of both DNM and ENM increases with time, serving as a negative prognostic factor. 27 Treatment of HPC is multidisciplinary and challenging.…”