Gross Tumor Resection Followed by Post-Operative Radiation Optimizes Local Control in Patients with Meningeal Hemangiopericytoma: An Update on a Single Institutional Experience

Abstract

<h3>Purpose/Objective(s)</h3> Meningeal hemangiopericytomas (M-HPCs) are vascularized mesenchymal tumors with aggressive behavior, commonly arising intracranially. The ideal treatment regimen for M-HPC varies from institution to institution, given its rare incidence. We have previously reported that both gross tumor resection (GTR) and post-operative radiotherapy (PORT) independently correlate with improved local control (LC), and that GTR followed by PORT at a dose ≥ 60 Gy improves LC. Here, we provide an update to those initial findings with extended follow-up in an expanded cohort of patients. <h3>Materials/Methods</h3> A single-institution retrospective analysis was conducted by reviewing the medical records of patients presenting with localized M-HPC at to a tertiary referral cancer center, between 1979 and 2021. The Kaplan-Meier method was used estimate actuarial LC, metastasis-free survival (MFS), and overall survival (OS). <h3>Results</h3> We identified 82 patients diagnosed between 1979 and 2021 with localized M-HPC that were treated with surgery alone (n=36) or surgery + PORT (n=46). Most patients were male (n=48, 59%), with a median age of 41 years (interquartile range 34-52). Median follow-up was 114 months. Most patients had intracranial tumors arising in the supratentorial region (n=50, 61%). There were also 5 patients who presented with disease in the cervical spine (6%). GTR was accomplished in 39 patients (49%) versus subtotal resection (STR) in 29 (37%), and unknown status in 14 patients (14%). PORT was delivered to the majority of patients (n=46, 56%). For the entire cohort, 5- and 10-year OS were 91% and 66%, and 5- and 10-year LC were 65% and 34%. Additionally, 5- and 10-year MFS were 82% and 41%. Undergoing GTR was associated with improved LC (HR 0.40, p=0.014). Similarly, PORT resulted in improved LC relative to patients who underwent surgery alone (HR 0.27, p<0.0001). Patients who underwent a GTR followed by PORT had superior LC compared to patients who had GTR alone (HR 0.18, p=0.001). Among intracranial tumors, patients receiving adjuvant radiation equivalent-dose in 2 Gy fractions (EQD2) ≥ 60 Gy (n=15) had improved LC relative to EQD2 doses of < 60 Gy (n=16) (HR 0.20, p=0.011). Age, gender, and PORT did not correlate with differences in OS or MFS. <h3>Conclusion</h3> Our data in this expanded cohort with prolonged follow-up demonstrate that among patients with M-HPC, PORT and GTR each independently improve LC. However, the combination of both GTR followed by PORT is superior to GTR alone for LC and should remain standard of care. Additionally, for patients with intracranial disease, PORT EQD2 doses ≥ 60 Gy should be used to improve LC.