A Multi-Disciplinary Approach to Diagnosis and Treatment of Radionecrosis in Malignant Gliomas and Cerebral Metastases

Abstract

Radiation necrosis represents a potentially devastating complication after radiation therapy in brain tumors. The establishment of the diagnosis and especially the differentiation from progression and pseudoprogression with its therapeutic implications requires interdisciplinary consent and monitoring. Herein, we want to provide an overview of the diagnostic modalities, therapeutic possibilities and an outlook on future developments to tackle this challenging topic. The aim of this report is to provide an overview of the current morphological, functional, metabolic and evolving imaging tools described in the literature in order to (I) identify the best criteria to distinguish radionecrosis from tumor recurrence after the radio-oncological treatment of malignant gliomas and cerebral metastases, (II) analyze the therapeutic possibilities and (III) give an outlook on future developments to tackle this challenging topic. Additionally, we provide the experience of a tertiary tumor center with this important issue in neuro-oncology and provide an institutional pathway dealing with this problem.

Tumor Location Impacts the Development of Radiation Necrosis in Benign Intracranial Tumors

“…However, in our study, we also included those limited to imaging-based diagnoses of RN, potentially leading to a higher incidence thereof. On the other hand, due to research in past years [20], we established a MRI protocol including diffusion-weighted sequence (DTI), post-contrast transverse T1-weighted magnetization-prepared rapid gradient-echo sequence (MPRAGE), as well as Perfusion-Weighted Imaging, as recently published by Mangesius et al [41]. This MRI protocol allowed us to identify RN with higher accuracy and might also lead to a higher incidence of RN.…”

Comparative study of dynamic conformal arc therapy and volumetric modulated arc therapy for treating single brain metastases: A retrospective analysis of dosimetric and clinical outcomes

“…A contrast enhancement inside the previously treated BM suggested a LR or a RN. To differentiate both, 18-fluorodeoxyglucose (FDG) PET-CT, surgery, corticosteroids test or a new MRI in a short interval were realized [20] , [21] , [22] , [23] .…”

Mismatch Between Brain MRIs and 18F-DOPA PET/CT

“…Local relapse of the irradiated metastasis was suspected 14 months after the SRT_1 because of a morphological progression combined with a local neoangiogenesis (increased relative cerebral blood volume, ×2.4). A first 18 F-DOPA PET/CT (PET 1 ) confirmed the local relapse (lesion uptake superior to contralateral striatum uptake and tumor-to-background ratio >2, A ) with 3 other focal 18 F-DOPA uptakes 6–8 . When retrospectively analyzing the 1.5 T brain MRI, no unequivocal morphological correlation was found for 2 18 F-DOPA uptakes ( B and C ), whereas the third 18 F-DOPA uptake matched with a linear contrast enhancement on the MRI, which had been initially interpreted as artifactual ( D ).…”

“…A first 18 F-DOPA PET/CT (PET 1 ) confirmed the local relapse (lesion uptake superior to contralateral striatum uptake and tumor-to-background ratio >2, A) with 3 other focal 18 F-DOPA uptakes. [6][7][8] When retrospectively analyzing the 1.5 T brain MRI, no unequivocal morphological correlation was found for 2 18 F-DOPA uptakes (B and C), whereas the third 18 F-DOPA uptake matched with a linear contrast enhancement on the MRI, which had been initially interpreted as artifactual (D). After multidisciplinary board, a second course of radiotherapy 9 (SRT_2: 27G in 3 fractions) 10 to the relapsing cerebellar metastasis was delivered and erlotinib was continued.…”