Re-irradiation for Recurrent Primary Brain Tumors

Abstract

Abstract. Background: Historically, radiation oncologists have been cautious about re-irradiating brain tumors because of concerns about the risks of late central nervous system (CNS) toxicity, especially radionecrosis, that may occur several months to years following treatment. Today there are still limited prospective data addressing this approach. Materials and Methods: Systematic review of published trials reporting clinical results after re-irradiation of patients with different types of brain tumors was performed. Results: Data mainly related to glioblastoma, anaplastic glioma, medulloblastoma, ependymoma and meningioma have been published. Randomized studies are scarce. As in first-line scenarios, efficacy of radiotherapy is influenced by histology. Based on the reported outcomes, preliminary recommendations for dose/fractionation regimens can be given. Conclusion: Re-irradiation of brain tumors is increasingly considered as our understanding of brain tolerance to radiation evolves and developments in radiation technology and imaging make highly accurate targeting of recurrent tumors possible. With developments in systemic therapy, further exploration of the role of re-irradiation on its own or in combination with novel agents is needed.The current postoperative standard treatment for glioblastoma (GBM) is radiotherapy with concurrent and adjuvant temozolomide. With this approach, 5-year overall survival is 9.8% compared to 1.9% with radiotherapy alone (1). Recent data suggest that maintenance therapy with tumor-treating fields in addition to temozolomide improves survival (2). Efforts have been made to standardize the target volume definition (3). Nevertheless, despite an increase in survival rates, the majority of patients progress within 10-15 months. Also for anaplastic astrocytomas and low-grade gliomas, radiotherapy remains a common first-line treatment. In these tumors, the time to progression is longer but the majority ultimately also recurs. Salvage therapy is indicated in the majority of recurrent gliomas and most patients receive systemic therapy and/or surgery at relapse.Historically, many radiation oncologists have been cautious about re-irradiating brain tumors because of concerns about the risks of toxicity, e.g., radionecrosis. Reirradiation for brain tumors is now more frequently used because developments in radiation technology and imaging allow for highly accurate targeting of biologically relevant tumor volumes and, furthermore, several studies have demonstrated the feasibility of this treatment paradigm. This review summarizes radiobiological principles behind reirradiation of different types of brain tumors and discusses the current evidence from clinical studies. Overview of Treatment Options for Recurrent GliomasExternal-beam radiotherapy is an integral part of treatment of low-and high-grade gliomas. At relapse, treatment options have included further surgical resection, systemic therapy, including prospective trials of new agents, and re-irradiation. Currently, however, there is ...

Bevacizumab as a last-line treatment for glioblastoma following failure of radiotherapy, temozolomide and lomustine

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Pediatric Ependymoma: A Proteomics Perspective

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Recurrent Malignant Gliomas: Treatment Options and Their Effect on Patient's Quality of Life

“…There is no class 1 evidence to guide therapy; hence, careful employment of treatment strategies is critical to not exacerbate morbidity or cause a decline in QoL (8). Treatment options include repeat surgery, re-irradiation, or deployment of systemic chemotherapy and/or anti-angiogenic agents.…”

“…Treatment options include repeat surgery, re-irradiation, or deployment of systemic chemotherapy and/or anti-angiogenic agents. Recently, the use of TTF in combination with these options has been considered (8). Recurrent tumor amenable to surgical removal is removed and a greater degree of resection at that stage can impact OS (4).…”

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