Clinical Characteristics of Gliosarcoma and Outcomes From Standardized Treatment Relative to Conventional Glioblastoma

Abstract

Background: Gliosarcoma (GS) is a rare histopathologic variant of glioblastoma (GBM) characterized by a biphasic growth pattern consisting of both glial and sarcomatous components. Reports regarding its relative prognosis compared to conventional GBM are conflicting and although GS is treated as conventional GBM, supporting evidence is lacking. The aim of this study was to characterize demographic trends, clinical outcomes and prognostic variables of GS patients receiving standardized therapy and compare these to conventional GBM. Methods: Six hundred and eighty GBM patients, treated with maximal safe resection followed by radiotherapy with concomitant and adjuvant temozolomide at a single institution, were retrospectively reevaluated by reviewing histopathological records and tumor tissue for identification of GS patients. Clinico-pathological-and tumor growth characteristics were obtained via assessment of medical records and imaging analysis. Kaplan-Meier survival estimates were compared with log-rank testing, while Cox-regression modeling was tested for prognostic factors in GS patients. Results: The cohort included 26 primary gliosarcoma (PGS) patients (3.8%) and 7 secondary gliosarcoma (SGS) patients (1.0%). Compared to conventional GBM tumors, PGS tumors were significantly more often MGMT-unmethylated (73.9%) and located in the temporal lobe (57.7%). GS tumors often presented dural contact, while extracranial metastasis was only found in 1 patient. No significant differences were found between PGS and conventional GBM in progression-free-survival (6.8 and 7.6 months, respectively, p = 0.105) and in overall survival (13.4 and 15.7 months, respectively, p = 0.201). Survival following recurrence was not significantly different between PGS, SGS, and GBM. Temporal tumor location and MGMT status were found associated with PGS survival (p = 0.036 and p = 0.022, respectively). Conclusion: Despite histopathological and location difference between GS and GBM tumors, the patients present similar survival outcome from standardized treatment. These findings support continued practice of radiation and temozolomide for GS patients.

Spinal metastasis of glioblastoma multiforme before gliosarcomatous transformation: a case report

“…These types of tumors may spread to the spinal subarachnoid space through direct extension, through the lymphatic system, from the bloodstream, and through the CSF. The involvement of the lateral or third ventricle (and the fourth ventricle in a few cases) is GS is a rare histopathological variant of isocitrate dehydrogenase (IDH) wild-type GBM, and its corresponding median survival time after diagnosis is 6-14.8 months [5,7,13]. According to a literature review, secondary GS is extremely rare and has not been detected in patients with GBM.…”

“…Gliosarcoma (GS) is a rare GBM type composed of separate gliomatous and sarcomatous components [4,5]. GS accounts for 1.8-8% of GBM cases and 0.48% of all intracranial tumor cases [6,7]. Most types of GS are de novo and are thus termed "primary GS," and those preceded by operative resection, radiotherapy, or chemotherapy are termed "secondary GS" [6][7][8].…”

Determining the applicability of the RSNA radiology lexicon (RadLex) in high-grade glioma MRI reporting – a preliminary study on 20 consecutive cases with newly diagnosed glioblastoma

“…The de nite con rmation of GBM diagnosis (19X primary GBM, 1X primary gliosarcoma) was established by our colleagues of the department of neuropathology in all cases. A gliosarcoma is a rare biphasic glial and sarcomatous variant of GBM with similar prognosis following standard treatment (Frandsen 2019) [14]. Pathological diagnoses of all included grade 4 astrocytic tumors (GBM, gliosarcoma) were based on the well-established criteria set out in the contemporary fourth edition of the World Health Organization classi cation of tumors of the central nervous system (Louis 2007) [15].…”

Genetic alteration and clonal evolution of primary glioblastoma into secondary gliosarcoma

“…2 Patients with gliosarcoma and GBM show similarly poor survival outcomes and are typically treated using the same regimen including maximal safe resection, and concomitant radiotherapy and chemotherapy. [3][4][5][6] The pathogenesis of gliosarcoma remains unclear. One hypothesis states that the gliomatous and sarcomatous components originate from different progenitor cells, with the sarcomatous element arising from vascular smooth muscle cells, pluripotent mesenchymal cells of the perivascular adventitia, fibroblasts, or even histolytic cells.…”