Intraoperative Radiotherapy in Brain Malignancies: Indications and Outcomes in Primary and Metastatic Brain Tumors

Abstract

Despite the continued controversy over defining an optimal delivery mechanism, the critical role of adjuvant radiation in the management of surgically resected primary and metastatic brain tumors remains one of the universally accepted standards in neuro-oncology. Local disease control still ranks as a significant predictor of survival in both high-grade glioma and treated intracranial metastases with radiation treatment being essential in maximizing tumor control. As with the emergence and eventual acceptance of cranial stereotactic radiosurgery (SRS) following an era dominated by traditional radiotherapy, evidence to support the use of intraoperative radiotherapy (IORT) in brain tumors requiring surgical intervention continues to accumulate. While the clinical trial strategies in treating glioblastoma with IORT involve delivery of a boost of cavitary radiation prior to the planned standard external beam radiation, the use of IORT in metastatic disease offers the potential for dose escalation to the level needed for definitive adjuvant radiation, eliminating the need for additional episodes of care while providing local control equal or superior to that achieved with SRS in a single fraction. In this review, we explore the contemporary clinical data on IORT in the treatment of brain tumors along with a discussion of the unique dosimetric and radiobiological factors inherent in IORT that could account for favorable outcome data beyond those seen in other techniques.

Stereotactic radiosurgery for post operative brain metastasic surgical cavities: a single institution experience

“…In this context, different others modalities of adjuvant radiotherapy are currently assessed in a goal to improve local control and/ or reduce brain toxicity such as intraoperative radiotherapy or intra operative brachytherapy; several published studies have reported a high variability in term of one-year-local control, from 50% [ 31 ] to 88% with a low rate of radionecrosis (7%) [ 32 ]. Larger prospective studies are needed to confirm these favorable results including combination with systemic treatment [ 33 ]. The role of a novel collagen Tile cesium brachytherapy is currently in tested.…”

Oncolytic viral therapy as promising immunotherapy against glioma

“…To delay tumor recurrence, radiotherapy and chemotherapy are used as adjuvant therapies 35 . Radiation therapy is an important supplement to glioma treatment, with conventional radiation doses of 50–60 Gy 36–38 . It may be possible to conduct radiotherapy using an external source, an internal source, or radioactive monoclonal antibodies 39 .…”

“…35 Radiation therapy is an important supplement to glioma treatment, with conventional radiation doses of 50-60 Gy. [36][37][38] It may be possible to conduct radiotherapy using an external source, an internal source, or radioactive monoclonal antibodies. 39 Temozolomide (TMZ) is a first-line agent for GBM therapy, 40 but some patients with TMZresistance have less than ideal therapeutic effect.…”

Management Strategies for Large Brain Metastases

“…While SRS and WBRT have been extensively evaluated in the last few decades for management of brain metastases, another mode of radiation therapy that is increasingly gaining attention is intraoperative radiotherapy (IORT) (64). IORT involves a single dose of radiation administered at the same time as the surgical biopsy or resection being performed.…”