Evaluation of brain edema formation defined by MRI after LINAC-based stereotactic radiosurgery

Abstract

BackgroundPeri-lesional edema is a serious and well-known complication of stereotactic radiosurgery (SRS). Here we evaluated edema risk after SRS and assessed its formation and resolution dynamics.Patients and methods107 patients underwent SRS for heterogeneous diagnoses: 34 (29%) with arteriovenous malformations, 38 (35%) with meningiomas, 16 (15%) with metastatic tumors, 16 (15%) with acoustic neuromas, 3 with (3%) cavernomas, and 2 (2%) each with anaplastic astrocytomas and anaplastic oligoastrocytomas. Edema area was delineated in MRI T2-FLAIR sequences 0, 6, 12, 18, 24, 30, and 38 months after treatment. Lesion location was defined as either above (n = 80) or below (n = 32) the “Frankfurt modified line” (FML).Results17% of patients developed or had worsening post-treatment edema. Edema volume was maximal at 6 months (mean 7.2, SD 1.2) post radiosurgery. Post-SRS edema was 5.1 (1.06 – 24.53) times more likely in patients with lesions above the FML. There was no association between edema development and age, PTV size, number of beams, and diagnosis (p = 0.07).ConclusionsRadiosurgery-associated edema develops within 6 months of treatment and decreases over time. Edema occurrence is strongly related to lesion location, and its presence is much more likely when the treated lesions are situated above the Frankfurt line.

Treatment of Intracranial Tumors With Stereotactic Radiosurgery: Short-Term Results From Cuba

“…Edema associated with SRS is well known. In a study conducted by Harat M et al [ 38 ] in a heterogeneous population of patients treated with SRS, edema was observed in 17% of cases. These authors found no association between the presence of edema and tumor size, dose escalation, or histopathological diagnosis.…”

“…It has been observed that edema increases during the first 6-9 months of SRS and begins to decrease after this period [ 38 ]. Not all cerebral edemas are symptomatic or require treatment.…”

Optimal timing and sequence of combining stereotactic radiosurgery with immune checkpoint inhibitors in treating brain metastases: clinical evidence and mechanistic basis

“…However, the follow-up of this study is rather short. As an indirect phenomenon, the volume of brain edema develops within 6 months and lasts for months or even years after SRS or WBRT [ 87 ]. A recently published meta-analysis summarizing the clinical and preclinical impact of conventional photon RT on BBB permeability revealed that there were increased permeabilities in all acute (< 1 month), early delayed (1–6 months), and late-delayed (> 6 months) follow-up categories [ 88 ].…”

“…Moreover, the translocation or secretion level of DAMPs seemed to correlate with the radiation dose positively [ 92 ]. However, excessively high doses can cause damage to surrounding healthy tissues and organs, for example, brain edema develops within 6 months and lasts for months or even years after SRS or WBRT [ 87 ]. Vanpouille ‘s study showed that Trex1 could be induced by radiation doses above 12–18 Gy, regardless of cancer type.…”

Quantifying effects of radiotherapy-induced microvascular injury; review of established and emerging brain MRI techniques

“…Currently available advanced radiotherapy techniques applying limited and fractionated doses have decreased the risk of symptomatic and debilitating brain oedema, as well as the need for treatment [31]. The risk of developing oedema is higher with stereotactic radiosurgery (SRS) than with fractionated radiation therapy [32,33]. Because vasogenic brain oedema can be challenging to detect on MRI, its prevalence is not well known.…”