An analysis of radiation necrosis of the central nervous system treated with bevacizumab

Symptomatic brain metastases in melanoma

Although clinical outcomes in metastatic melanoma have improved in recent years, the morbidity and mortality of symptomatic brain metastases remain challenging. Response rates and survival outcomes of patients with symptomatic melanoma brain metastases (MBM) are significantly inferior to patients with asymptomatic disease. This review focusses upon the specific challenges associated with the management of symptomatic MBM, discussing current treatment paradigms, obstacles to improving clinical outcomes and directions for future research.

The dilemma of radiation necrosis from diagnosis to treatment in the management of brain metastases

Radiation therapy with stereotactic radiosurgery (SRS) or whole brain radiation therapy is a mainstay of treatment for patients with brain metastases. The use of SRS in the management of brain metastases is becoming increasingly common and provides excellent local control. Cerebral radiation necrosis (RN) is a late complication of radiation treatment that can be seen months to years following treatment and is often indistinguishable from tumor progression on conventional imaging. In this review article, we explore risk factors associated with the development of radiation necrosis, advanced imaging modalities used to aid in diagnosis, and potential treatment strategies to manage side effects.

Adverse radiation effect versus tumor progression following stereotactic radiosurgery for brain metastases: Implications of radiologic uncertainty

BACKGROUND

Adverse radiation effect (ARE) following stereotactic radiosurgery (SRS) for brain metastases is challenging to distinguish from tumor progression. This study characterizes the clinical implications of radiologic uncertainty (RU).

METHODS

Cases reviewed retrospectively at a single-institutional, multi-disciplinary SRS Tumor Board between 2015-2022 for RU following SRS were identified. Treatment history, diagnostic or therapeutic interventions performed upon RU resolution, and development of neurologic deficits surrounding intervention were obtained from the medical record. Differences in lesion volume and maximum diameter at RU onset versus resolution were compared with paired t-tests. Median time from RU onset to resolution was estimated using the Kaplan-Meier method. Univariate and multivariate associations between clinical characteristics and time to RU resolution were assessed with Cox proportional-hazards regression.

RESULTS

Among 128 lesions with RU, 23.5% had undergone ≥ 2 courses of radiation. Median maximum diameter (20 vs. 16 mm, p < 0.001) and volume (2.7 vs. 1.5 cc, p < 0.001) were larger upon RU resolution versus onset. RU resolution took > 6 and > 12 months in 25% and 7% of cases, respectively. Higher total EQD2 prior to RU onset (HR = 0.45, p = 0.03) and use of MR perfusion (HR = 0.56, p = 0.001) correlated with shorter time to resolution; larger volume (HR = 1.05, p = 0.006) portended longer time to resolution. Most lesions (57%) were diagnosed as ARE. Most patients (58%) underwent an intervention upon RU resolution; of these, 38% developed a neurologic deficit surrounding intervention.

CONCLUSIONS

RU resolution took > 6 months in > 25% of cases. RU may lead to suboptimal outcomes and symptom burden. Improved characterization of post-SRS RU is needed.

Low-Dose Bevacizumab for the Treatment of Focal Radiation Necrosis of the Brain (fRNB): A Single-Center Case Series

Focal radiation necrosis of the brain (fRNB) is a late adverse event that can occur following the treatment of benign or malignant brain lesions with stereotactic radiation therapy (SRT) or stereotactic radiosurgery (SRS). Recent studies have shown that the incidence of fRNB is higher in cancer patients who received immune checkpoint inhibitors. The use of bevacizumab (BEV), a monoclonal antibody that targets the vascular endothelial growth factor (VEGF), is an effective treatment for fRNB when given at a dose of 5-7.5 mg/kg every two weeks. In this single-center retrospective case series, we investigated the effectiveness of a low-dose regimen of BEV (400 mg loading dose followed by 100 mg every 4 weeks) in patients diagnosed with fRNB. A total of 13 patients were included in the study; twelve of them experienced improvement in their existing clinical symptoms, and all patients had a decrease in the volume of edema on MRI scans. No clinically significant treatment-related adverse effects were observed. Our preliminary findings suggest that this fixed low-dose regimen of BEV can be a well-tolerated and cost-effective alternative treatment option for patients diagnosed with fRNB, and it is deserving of further investigation.

Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal GRASP Dynamic Contrast-Enhanced MRI

BACKGROUND

Differentiating brain metastasis progression from radiation effects or radiation necrosis (RN) remains challenging. Golden-angle radial sparse parallel (GRASP) dynamic contrast-enhanced MRI provides high spatial and temporal resolution to analyze tissue enhancement, which may differ between tumor progression (TP) and RN.

OBJECTIVE

To investigate the utility of longitudinal GRASP MRI in distinguishing TP from RN after gamma knife stereotactic radiosurgery (SRS).

METHODS

We retrospectively evaluated 48 patients with brain metastasis managed with SRS at our institution from 2013 to 2020 who had GRASP MRI before and at least once after SRS. TP (n = 16) was pathologically confirmed. RN (n = 16) was diagnosed on either resected tissue without evidence of tumor or on lesion resolution on follow-up. As a reference, we included a separate group of patients with non-small-cell lung cancer that showed favorable response with tumor control and without RN on subsequent imaging (n = 16). Mean contrast washin and washout slopes normalized to the superior sagittal sinus were compared between groups. Receiver operating characteristic analysis was performed to determine diagnostic performance.

RESULTS

After SRS, progression showed a significantly steeper washin slope than RN on all 3 follow-up scans (scan 1: 0.29 ± 0.16 vs 0.18 ± 0.08, P = .021; scan 2: 0.35 ± 0.19 vs 0.18 ± 0.09, P = .004; scan 3: 0.32 ± 0.12 vs 0.17 ± 0.07, P = .002). No significant differences were found in the post-SRS washout slope. Post-SRS washin slope differentiated progression and RN with an area under the curve (AUC) of 0.74, a sensitivity of 75%, and a specificity of 69% on scan 1; an AUC of 0.85, a sensitivity of 92%, and a specificity of 69% on scan 2; and an AUC of 0.87, a sensitivity of 63%, and a specificity of 100% on scan 3.

CONCLUSION

Longitudinal GRASP MRI may help to differentiate metastasis progression from RN.

Management of initial and recurrent radiation-induced contrast enhancements following radiotherapy for brain metastases: Clinical and radiological impact of bevacizumab and corticosteroids

Purpose

The appearance of radiation-induced contrast enhancements (RICE) after radiotherapy for brain metastases can go along with severe neurological impairments. The aim of our analysis was to evaluate radiological changes, the course and recurrence of RICE and identify associated prognostic factors.

Methods

We retrospectively identified patients diagnosed with brain metastases, who were treated with radiotherapy and subsequently developed RICE. Patient demographic and clinical data, radiation-, cancer-, and RICE-treatment, radiological results, and oncological outcomes were reviewed in detail.

Results

A total of 95 patients with a median follow-up of 28.8 months were identified. RICE appeared after a median time of 8.0 months after first radiotherapy and 6.4 months after re-irradiation. Bevacizumab in combination with corticosteroids achieved an improvement of clinical symptoms and imaging features in 65.9% and 75.6% of cases, respectively, both significantly superior compared to treatment with corticosteroids only, and further significantly prolonged RICE-progression-free survival to a median of 5.6 months. Recurrence of RICE after initially improved or stable imaging occurred in 63.1% of cases, significantly more often in patients after re-irradiation and was associated with high mortality of 36.6% after the diagnosis of flare-up. Response of recurrence significantly depended on the applied treatment and multiple courses of bevacizumab achieved good response.

Conclusion

Our results suggest that bevacizumab in combination with corticosteroids is superior in achieving short-term imaging and symptom improvement of RICE and prolongs the progression-free time compared to corticosteroids alone. Long-term RICE flare-up rates after bevacizumab discontinuation are high, but repeated treatments achieved effective symptomatic control.

Iatrogenic Influence on Prognosis of Radiation-Induced Contrast Enhancements in Patients with Glioma WHO 1-3 following Photon and Proton Radiotherapy

BACKGROUND AND PURPOSE

Radiation-induced contrast enhancement (RICE) is a common side effect following radiotherapy for glioma, but both diagnosis and handling are challenging. Due to the potential risks associated with RICE and its challenges in differentiating RICE from tumor progression, it is critical to better understand how RICE prognosis depends on iatrogenic influence.

MATERIALS AND METHODS

We identified 99 patients diagnosed with RICE who were previously treated with either photon or proton therapy for World Health Organization (WHO) grade 1-3 primary gliomas. Post-treatment brain MRI-based volumetric analysis and clinical data collection was performed at multiple time points.

RESULTS

The most common histologic subtypes were astrocytoma (50%) and oligodendroglioma (46%). In 67%, it was graded WHO grade 2 and in 86% an IDH mutation was present. RICE first occurred after 16 months (range: 1 - 160) in median. At initial RICE occurrence, 39% were misinterpreted as tumor progression. A tumor-specific therapy including chemotherapy or re-irradiation led to a RICE size progression in 86% and 92% of cases, respectively and RICE symptom progression in 57% and 65% of cases, respectively. A RICE-specific therapy such as corticosteroids or Bevacizumab for larger or symptomatic RICE led to a RICE size regression in 81% of cases with symptom stability or regression in 62% of cases.

CONCLUSIONS

While with chemotherapy and re-irradiation a RICE progression was frequently observed, anti-edematous or anti-VEGF treatment frequently went along with a RICE regression. For RICE, correct diagnosis and treatment decisions are challenging and critical and should be made interdisciplinarily.

Bevacizumab is an effective treatment for symptomatic cerebral necrosis after carbon ion therapy for recurrent intracranial malignant tumours: A case report

Carbon ion therapy (CIT) is a form of particle therapy, which not only spares normal tissues but may also improve local control of recurrent intracranial tumours. Cerebral radiation necrosis (RN) is one of the most serious adverse reactions of recurrent brain tumours following reirradiation, which may lead to neurological decline or even death. Bevacizumab is an anti-vascular endothelial growth factor antibody, which has been used to treat symptomatic RN. However, studies on bevacizumab for the treatment of CIT-induced RN are sparse. The present study described two cases that were successfully treated with bevacizumab for symptomatic RN following CIT for recurrent intracranial malignant tumours. The two recurrent intracranial malignant tumours, a chondrosarcoma in the right cavernous sinus and an anaplastic meningioma in the right frontal lobe, were enrolled in a clinical trial of CIT. Both cases were treated intravenously with bevacizumab when deterioration that appeared to be symptomatic brain RN was observed. Just before CIT, enhanced magnetic resonance imaging (MRI) was performed in each case to confirm tumour recurrence. Both cases exhibited a deterioration in symptoms, as well as on MRI, at 12-month intervals following CIT. The first case underwent positron emission tomography/computed tomography to confirm no increase in fluorodeoxyglucose uptake in lesion areas. Both cases were diagnosed as having symptomatic brain RN and began intravenous administration of four cycles of 5 mg/kg bevacizumab biweekly. The patients responded well, with rapid and marked improvements on MRI, and in clinical symptoms. No tumour progression was observed 24 months after CIT. In conclusion, bevacizumab was revealed to exert marked effects on symptomatic brain RN following CIT. Notably, cycles of bevacizumab should be administered specifically based on the aim of treating brain necrosis, and long-term or prophylactic applications are not recommended.

Efficacy and safety of apatinib in radiation-induced brain injury among head and neck cancer: an open-label, single-arm, phase 2 study

BACKGROUND

The treatment of radiation-induced brain injury (RI) caused by radiotherapy for head and neck cancer is challenging. Antiangiogenic therapy is a promising treatment. Apatinib is an oral tyrosine kinase inhibitor (TKI) that selectively inhibits vascular endothelial growth factor receptor (VEGFR) 2. We aimed to assess the efficacy and safety of apatinib in patients with RI.

PATIENTS AND METHODS

In this phase 2, open-label, single-arm, prospective study, we recruited patients aged 35-80 years with prior radiotherapy history for head and neck cancer who had newly diagnosed RI at the Sun Yat-sen Memorial Hospital, China. Apatinib was administered at a dosage of 250 mg once daily orally for 4 weeks. A Simon's mini-max two-stage design was performed. The primary outcome was the proportion of patients with an overall clinical efficacy defined as radiographic response ≥ 25% reduction in baseline brain edema volume on magnetic resonance (MR) fluid attenuated inversion recovery (FLAIR) images at week 4. Secondary endpoints were overall improvement rate of brain necrosis, neurological function, and safety.

RESULTS

We screened 37 patients, 36 of whom were enrolled between October 17, 2019 and August 3, 2020. At the cutoff date, 36 patients were assessed for efficacy and safety (19 to stage 1 and 17 to stage 2). Of the 36 patients evaluated for overall clinical efficacy, 22 patients (61.1%; 95%CI 43.5-76.9%) achieved the primary endpoint at week 4. Among the 31 patients with brain necrosis lesions, 19 patients (61.3%; 95%CI 42.2%-78.2%) showed improvement of brain necrosis. The most common grade 1 to 2 adverse events were hand-foot syndrome, fatigue and hypertension There were no treatment-related grade 4-5 toxicities.

CONCLUSION

Oral apatinib shows promising efficacy and is well-tolerated in patients with RI. Further randomized controlled studies are warranted.

TRIAL REGISTRATION

ClinicalTrials.gov (ID: NCT04152681).

Treatment and prophylaxis of radiation optic neuropathy: A systematic review and meta-analysis

PURPOSE

Radiation optic neuropathy (RON) generally follows radiation therapy that exceed 50 Gy to the visual axis and occurs within three years of therapy. Currently, there are no universally accepted treatments or prophylaxis for RON. The review aimed to examine the efficacy of all treatments and prophylaxis for RON.

METHODS

MEDLINE, Embase, the Cochrane Library, and gray literature were searched to December 2020. Studies on treatment(s) and/or prophylaxis of RON were included. Results were meta-analyzed using a random-effects model. Primary outcomes included the proportions of patients who experienced improvement, no change, or worsening of visual acuity (VA) for each treatment. Secondary outcome was the incidence of RON for studies on prophylaxis.

RESULTS

Overall, 50 studies (n = 5397) were included. Meta-analysis (n = 1752) showed significantly lower incidence of RON in patients who underwent intravitreal anti-VEGF prophylaxis compared to control (RR 0.64, 95%CI [0.48, 0.86]) for uveal melanoma. Intravitreal anti-VEGF injections (n = 68), hyperbaric oxygen therapy alone (n = 14), and pentoxifylline (n = 5) resulted in improved or stable vision ≤1 logMAR in 54.5%, 42.9%, and 40.0% of patients, respectively. Systemic corticosteroids (n = 82), anticoagulants (n = 12), and systemic bevacizumab (n = 7) showed improved or stable vision ≤1 logMAR in 17.1%, 33.3%, and 14.3% of patients, respectively. Overall risk of bias was low, but evidence was limited to retrospective studies.

CONCLUSION

Intravitreal anti-VEGF injections reduced incidence of RON in irradiated uveal melanoma patients. Systemic corticosteroids, systemic bevacizumab, and warfarin alone are likely ineffective treatments. Early hyperbaric oxygen therapy and intravitreal anti-VEGF injections were most effective among those investigated and require further investigation.

Histopathology and surgical outcome of symptomatic treatment-related changes after gamma knife radiosurgery in patients with brain metastases

A late-onset treatment-related changes (TRCs), which represent radiographic radiation necrosis (RN), frequently occur after stereotactic radiosurgery (SRS) for brain metastases and often need surgical treatment. This study aimed to validate the true pathology and investigate clinical implication of surgically resected TRCs on advanced magnetic resonance imaging (MRI). Retrospective analyses of 86 patients who underwent surgical resection after radiosurgery of brain metastases were performed. Fifty-four patients displayed TRCs on preoperative MRI, comprising pure RN in 19 patients (TRC-RN group) and mixed viable tumor cells in 35 patients (TRC-PD group). Thirty-two patients revealed the consistent diagnosis of progressive disease in both MRI and histopathology (PD–PD group). The TRC-PD group showed larger prescription isodose volume (9.4 cm³) than the TRC-RN (4.06 cm³, p = 0.014) group and a shorter time interval from SRS to preoperative MRI diagnosis (median 4.07 months) than the PD–PD group (median 8.77 months, p = 0.004). Progression-free survival was significantly different among the three groups (p < 0.001), but not between TRC-RN and TRC-PD (post hoc test, p = 1.00), while no difference was observed in overall survival (p = 0.067). Brain metastases featured as TRCs after SRS frequently contained viable tumor cells. However, this histologic heterogeneity had a minor impact on benign local prognosis of TRCs after surgical resection.

Pseudoprogression in Glioblastoma: Role of Metabolic and Functional MRI-Systematic Review

Background: Glioblastoma is the most frequent malignant primitive brain tumor in adults. The treatment includes surgery, radiotherapy, and chemotherapy. During follow-up, combined chemoradiotherapy can induce treatment-related changes mimicking tumor progression on medical imaging, such as pseudoprogression (PsP). Differentiating PsP from true progression (TP) remains a challenge for radiologists and oncologists, who need to promptly start a second-line treatment in the case of TP. Advanced magnetic resonance imaging (MRI) techniques such as diffusion-weighted imaging, perfusion MRI, and proton magnetic resonance spectroscopic imaging are more efficient than conventional MRI in differentiating PsP from TP. None of these techniques are fully effective, but current advances in computer science and the advent of artificial intelligence are opening up new possibilities in the imaging field with radiomics (i.e., extraction of a large number of quantitative MRI features describing tumor density, texture, and geometry). These features are used to build predictive models for diagnosis, prognosis, and therapeutic response. Method: Out of 7350 records for MR spectroscopy, GBM, glioma, recurrence, diffusion, perfusion, pseudoprogression, radiomics, and advanced imaging, we screened 574 papers. A total of 228 were eligible, and we analyzed 72 of them, in order to establish the role of each imaging modality and the usefulness and limitations of radiomics analysis.

Predicted probabilities of brain injury after carbon ion radiotherapy for head and neck and skull base tumors in long-term survivors

BACKGROUND AND PURPOSE

We aimed to determine the risk factors for radiation-induced brain injury (RIBI¹) after carbon ion radiotherapy (CIRT) to predict their probabilities in long-term survivors.

MATERIALS AND METHODS

We evaluated 104 patients with head, neck, and skull base tumors who underwent CIRT in a regimen of 32 fractions and were followed up for at least 24 months. RIBI was assessed using the Common Terminology Criteria for Adverse Events.

RESULTS

The median follow-up period was 45.5 months; 19 (18.3 %) patients developed grade ≥2 RIBI. The maximal absolute dose covering 5 mL of the brain (D5ml) was the only significant risk factor for grade ≥2 RIBI in the multivariate logistic regression analysis (p = 0.001). The tolerance doses of D5ml for the 5% and 50% probabilities of developing grade ≥2 RIBI were estimated to be 55.4 Gy (relative biological effectiveness [RBE]) and 68.4 Gy (RBE) by a logistic model, respectively.

CONCLUSION

D5ml was most significantly associated with grade ≥2 RIBI and may enable the prediction of its probability.

Low-Dosage Bevacizumab Treatment: Effect on Radiation Necrosis After Gamma Knife Radiosurgery for Brain Metastases

Cerebral radiation necrosis (RN), a complication of Gamma Knife radiosurgery, is difficult to treat, although bevacizumab seems to be effective. However, clinical data pertaining to bevacizumab treatment for RN are scarce, and its high price is problematic. This study explored the effectiveness of low-dose bevacizumab for RN caused by Gamma Knife. We retrospectively analyzed 22 patients who suffered cerebral RN post-Gamma Knife, and received bevacizumab treatment because of the poor efficacy of glucocorticoids. Low-dose bevacizumab (3 mg/kg) was administered for two cycles at 2-week intervals. T1- and T2-enhanced magnetic resonance imaging (MRI) images were examined for changes in RN status. We also monitored the dose of glucocorticoid, Karnofsky Performance Status (KPS) score, and adverse drug reactions. The mean volume of RN lesions decreased by 45% on T1-weighted images with contrast enhancement, and by 74% on T2-weighted images. All patients discontinued the use of glucocorticoids. According to the KPS scores, all patients showed an improvement in their symptoms and neurological function. No side effects were observed. Low-dosage bevacizumab at a dose of 3 mg/kg every 2 weeks is effective for treating cerebral RN after Gamma knife for brain metastases.

The effect of surgery on radiation necrosis in irradiated brain metastases: extent of resection and long-term clinical and radiographic outcomes

OBJECTIVE

Radiation therapy is a cornerstone of brain metastasis (BrM) management but carries the risk of radiation necrosis (RN), which can require resection for palliation or diagnosis. We sought to determine the relationship between extent of resection (EOR) of pathologically-confirmed RN and postoperative radiographic and symptomatic outcomes.

METHODS

A single-center retrospective review was performed at an NCI-designated Comprehensive Cancer Center to identify all surgically-resected, previously-irradiated necrotic BrM without admixed recurrent malignancy from 2003 to 2018. Clinical, pathologic and radiographic parameters were collected. Volumetric analysis determined EOR and longitudinally evaluated perilesional T2-FLAIR signal preoperatively, postoperatively, and at 3-, 6-, 12-, and 24-months postoperatively when available. Rates of time to 50% T2-FLAIR reduction was calculated using cumulative incidence in the competing risks setting with last follow-up and death as competing events. The Spearman method was used to calculate correlation coefficients, and continuous variables for T2-FLAIR signal change, including EOR, were compared across groups.

RESULTS

Forty-six patients were included. Most underwent prior stereotactic radiosurgery with or without whole-brain irradiation (N = 42, 91%). Twenty-seven operations resulted in gross-total resection (59%; GTR). For the full cohort, T2-FLAIR edema decreased by a mean of 78% by 6 months postoperatively that was durable to last follow-up (p < 0.05). EOR correlated with edema reduction at last follow-up, with significantly greater T2-FLAIR reduction with GTR versus subtotal resection (p < 0.05). Among surviving patients, a significant proportion were able to decrease their steroid use: steroid-dependency decreased from 54% preoperatively to 15% at 12 months postoperatively (p = 0.001).

CONCLUSIONS

RN resection conferred both durable T2-FLAIR reduction, which correlated with EOR; and reduced steroid dependency.

Radiation Necrosis from Stereotactic Radiosurgery-How Do We Mitigate?

OPINION STATEMENT

Intracranial stereotactic radiosurgery (SRS) is an effective and convenient treatment for many brain conditions. Data regarding safety come mostly from retrospective single institutional studies and a small number of prospective studies. Variations in target delineation, treatment delivery, imaging follow-up protocols and dose prescription limit the interpretation of this data. There has been much clinical focus on radiation necrosis (RN) in particular, as it is being increasingly recognized on follow-up imaging. Symptomatic RN may be treated with medical therapy (such as corticosteroids and bevacizumab) with surgical resection being reserved for refractory patients. Nevertheless, RN remains a challenging condition to manage, and therefore upfront patient selection for SRS remains critical to provide complication-free control. Mitigation strategies need to be considered in situations where the baseline risk of RN is expected to be high-such as large target volume or re-irradiation. These may involve reduction in the prescribed dose or hypofractionated stereotactic radiation therapy (HSRT). Recently published guidelines and international meta-analysis report the benefit of HSRT in larger lesions, without compromising control rates. However, careful attention to planning parameters and SRS techniques still need to be adhered, even with HSRT. In cases where the risk is deemed to be high despite mitigation, a combination approach of surgery with or without post-operative radiation should be considered.

Iatrogenic cerebral radiation necrosis

Cerebral radiation necrosis is the most serious late reaction to high doses of ionising radiation to the brain, and its treatment is generally unsatisfactory. We present a patient who developed cerebral radiation necrosis after protracted fluoroscopy during repeated embolisations of an extracranial arteriovenous malformation. Treatment with bevacizumab (a humanised murine monoclonal antibody against vascular endothelial growth factor) was followed by neurological and radiological improvements.

Bevacizumab Treatment of Radiation-Induced Brain Necrosis: A Systematic Review

Background

Radiation brain necrosis (RBN) is a serious complication in patients receiving radiotherapy for intracranial disease. Many studies have investigated the efficacy and safety of bevacizumab in patients with RBN. In the present study, we systematically reviewed the medical literature for studies reporting the efficacy and safety of bevacizumab, as well as for studies comparing bevacizumab with corticosteroids.

Materials and Methods

We searched PubMed, Cochrane library, EMBASE, and ClinicalTrials.gov from their inception through 1 March, 2020 for studies that evaluated the efficacy and safety of bevacizumab in patients with RBN. Two investigators independently performed the study selection, data extraction, and data synthesis.

Results

Overall, the present systematic review included 12 studies (eight retrospective, two prospective, and two randomized control trials [RCTs]) involving 236 patients with RBN treated who were treated with bevacizumab. The two RCTs also had control arms comprising patients with RBN who were treated with corticosteroids/placebo (n=57). Radiographic responses were recorded in 84.7% (200/236) of patients, and radiographic progression was observed in 15.3% (36/236). Clinical improvement was observed in 91% (n=127) of responding patients among seven studies (n=113). All 12 studies reported volume reduction on T1 gadolinium enhancement MRI (median: 50%, range: 26%–80%) and/or T2 FLAIR MRI images (median: 59%, range: 48%–74%). In total, 46 responding patients (34%) had recurrence. The two RCTs revealed significantly improved radiographic response in patients treated with bevacizumab (Levin et al.: p = 0.0013; Xu et al.: p < 0.001). Both also showed clinical improvement (Levin et al.: NA; Xu et al.: p = 0.039) and significant reduction in edema volume on both T1 gadolinium enhancement MRI (Levin et al.: p=0.0058; Xu et al.: p=0.027) and T2 FLAIR MRI (Levin et al.: p=0.0149; Xu et al.: p < 0.001). Neurocognitive improvement was significantly better after 2 months of treatment in patients receiving bevacizumab than in those given corticosteroids, as assessed by the MoCA scale (p = 0.028). The recurrence rate and side effects of the treatments showed no significant differences.

Conclusions

Patients with RBN respond to bevacizumab, which can improve clinical outcomes and cognitive function. Bevacizumab appears to be more efficacious than corticosteroid-based treatment. The safety profile was comparable to that of the corticosteroids.

Bevacizumab for radiation necrosis following radiotherapy of brain metastatic disease: a systematic review & meta-analysis

Background

Radiotherapy is the mainstay of brain metastasis (BM) management. Radiation necrosis (RN) is a serious complication of radiotherapy. Bevacizumab (BV), an anti-vascular endothelial growth factor monoclonal antibody, has been increasingly used for RN treatment. We systematically reviewed the medical literature for studies reporting the efficacy and safety of bevacizumab for treatment of RN in BM patients.

Materials and methods

PubMed, Medline, EMBASE, and Cochrane library were searched with various search keywords such as “bevacizumab” OR “anti-VEGF monoclonal antibody” AND “radiation necrosis” OR “radiation-induced brain necrosis” OR “RN” OR “RBN” AND “Brain metastases” OR “BM” until 1st Aug 2020. Studies reporting the efficacy and safety of BV treatment for BM patients with RN were retrieved. Study selection and data extraction were carried out by independent investigators. Open Meta Analyst software was used as a random effects model for meta-analysis to obtain mean reduction rates.

Results

Two prospective, seven retrospective, and three case report studies involving 89 patients with RN treated with BV were included in this systematic review and meta-analysis. In total, 83 (93%) patients had a recorded radiographic response to BV therapy, and six (6.7%) had experienced progressive disease. Seven studies (n = 73) reported mean volume reductions on gadolinium-enhanced T1 (mean: 47.03%, +/− 24.4) and T2-weighted fluid-attenuated inversion recovery (FLAIR) MRI images (mean: 61.9%, +/− 23.3). Pooling together the T1 and T2 MRI reduction rates by random effects model revealed a mean of 48.58 (95% CI: 38.32–58.85) for T1 reduction rate and 62.017 (95% CI: 52.235–71.799) for T2W imaging studies. Eighty-five patients presented with neurological symptoms. After BV treatment, nine (10%) had stable symptoms, 39 (48%) had improved, and 34 (40%) patients had complete resolution of their symptoms. Individual patient data was available for 54 patients. Dexamethasone discontinuation or reduction in dosage was observed in 30 (97%) of 31 patients who had recorded dosage before and after BV treatment. Side effects were mild.

Conclusions

Bevacizumab presents a promising treatment strategy for patients with RN and brain metastatic disease. Radiographic response and clinical improvement was observed without any serious adverse events. Further class I evidence would be required to establish a bevacizumab recommendation in this group of patients.

Treatment-induced brain tissue necrosis: a clinical challenge in neuro-oncology

Cancer therapy-induced adverse effects on the brain are a major challenge in neuro-oncology. Brain tissue necrosis (treatment necrosis [TN]) as a consequence of brain directed cancer therapy remains an insufficiently characterized condition with diagnostic and therapeutic difficulties and is frequently associated with significant patient morbidity. A better understanding of the underlying mechanisms, improvement of diagnostic tools, development of preventive strategies, and implementation of evidence-based therapeutic practices are pivotal to improve patient management. In this comprehensive review, we address existing challenges associated with current TN-related clinical and research practices and highlight unanswered questions and areas in need of further research with the ultimate goal to improve management of patients affected by this important neuro-oncological condition.

Single- and Multifraction Stereotactic Radiosurgery Dose/Volume Tolerances of the Brain

PURPOSE

As part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy investigating normal tissue complication probability (NTCP) after hypofractionated radiation therapy, data from published reports (PubMed indexed 1995-2018) were pooled to identify dosimetric and clinical predictors of radiation-induced brain toxicity after single-fraction stereotactic radiosurgery (SRS) or fractionated stereotactic radiosurgery (fSRS).

METHODS AND MATERIALS

Eligible studies provided NTCPs for the endpoints of radionecrosis, edema, or symptoms after cranial SRS/fSRS and quantitative dose-volume metrics. Studies of patients with only glioma, meningioma, vestibular schwannoma, or brainstem targets were excluded. The data summary and analyses focused on arteriovenous malformations (AVM) and brain metastases.

RESULTS

Data from 51 reports are summarized. There was wide variability in reported rates of radionecrosis. Available data for SRS/fSRS for brain metastases were more amenable to NTCP modeling than AVM data. In the setting of brain metastases, SRS/fSRS-associated radionecrosis can be difficult to differentiate from tumor progression. For single-fraction SRS to brain metastases, tissue volumes (including target volumes) receiving 12 Gy (V12) of 5 cm³, 10 cm³, or >15 cm³ were associated with risks of symptomatic radionecrosis of approximately 10%, 15%, and 20%, respectively. SRS for AVM was associated with modestly lower rates of symptomatic radionecrosis for equivalent V12. For brain metastases, brain plus target volume V20 (3-fractions) or V24 (5-fractions) <20 cm³ was associated with <10% risk of any necrosis or edema, and <4% risk of radionecrosis requiring resection.

CONCLUSIONS

The risk of radionecrosis after SRS and fSRS can be modeled as a function of dose and volume treated. The use of fSRS appears to reduce risks of radionecrosis for larger treatment volumes relative to SRS. More standardized dosimetric and toxicity reporting is needed to facilitate future pooled analyses that can refine predictive models of brain toxicity risks.

Management of symptomatic radiation necrosis after stereotactic radiosurgery and clinical factors for treatment response

PURPOSE

Approximately 10% of patients who received brain stereotactic radiosurgery (SRS) develop symptomatic radiation necrosis (RN). We sought to determine the effectiveness of treatment options for symptomatic RN, based on patient-reported outcomes.

MATERIALS AND METHODS

We conducted a retrospective review of 217 patients with 414 brain metastases treated with SRS from 2009 to 2018 at our institution. Symptomatic RN was determined by appearance on serial magnetic resonance images (MRIs), MR spectroscopy, requirement of therapy, and development of new neurological complaints without evidence of disease progression. Therapeutic interventions for symptomatic RN included corticosteroids, bevacizumab and/or surgical resection. Patient-reported therapeutic outcomes were graded as complete response (CR), partial response (PR), and no response.

RESULTS

Twenty-six patients experienced symptomatic RN after treatment of 50 separate lesions. The mean prescription dose was 22 Gy (range, 15 to 30 Gy) in 1 to 5 fractions (median, 1 fraction). Of the 12 patients managed with corticosteroids, 6 patients (50%) reported CR and 4 patients (33%) PR. Of the 6 patients managed with bevacizumab, 3 patients (50%) reported CR and 1 patient (18%) PR. Of the 8 patients treated with surgical resection, all reported CR (100%). Other than surgical resection, age ≥54 years (median, 54 years; range, 35 to 81 years) was associated with CR (odds ratio = 8.40; 95% confidence interval, 1.27-15.39; p = 0.027).

CONCLUSION

Corticosteroids and bevacizumab are commonly utilized treatment modalities with excellent response rate. Our results suggest that patient's age is associated with response rate and could help guide treatment decisions for unresectable symptomatic RN.

Bevacizumab for pediatric radiation necrosis

Background

Radiation necrosis is a frequent complication occurring after the treatment of pediatric brain tumors; however, treatment options remain a challenge. Bevacizumab is an anti-VEGF monoclonal antibody that has been shown in small adult cohorts to confer a benefit, specifically a reduction in steroid usage, but its use in children has not been well described.

Methods

We describe our experience with bevacizumab use for symptomatic radiation necrosis at 5 institutions including patients treated after both initial irradiation and reirradiation.

Results

We identified 26 patients treated with bevacizumab for symptomatic radiation necrosis, with a wide range of underlying diagnoses. The average age at diagnosis of radiation necrosis was 10.7 years, with a median time between the last dose of radiation and the presentation of radiation necrosis of 3.8 months (range, 0.6-110 months). Overall, we observed that 13 of 26 patients (50%) had an objective clinical improvement, with only 1 patient suffering from significant hypertension. Radiological improvement, defined as reduced T2/fluid-attenuated inversion recovery signal and mass effect, was observed in 50% of patients; however, this did not completely overlap with clinical response. Both early and late radiation necrosis responded equally well to bevacizumab therapy. Overall, bevacizumab was very well tolerated, permitting a reduction of corticosteroid dose and/or duration in the majority of patients.

Conclusions

Bevacizumab appears to be effective and well-tolerated in children as treatment for symptomatic radiation necrosis and warrants more robust study in the context of controlled clinical trials.

A Radiomics Model for Predicting the Response to Bevacizumab in Brain Necrosis after Radiotherapy

PURPOSE

Bevacizumab is considered a promising therapy for brain necrosis after radiotherapy, while some patients fail to derive benefit or even worsen. Hence, we developed and validated a radiomics model for predicting the response to bevacizumab in patients with brain necrosis after radiotherapy.

EXPERIMENTAL DESIGN

A total of 149 patients (with 194 brain lesions; 101, 51, and 42 in the training, internal, and external validation sets, respectively) receiving bevacizumab were enrolled. In total, 1,301 radiomic features were extracted from the pretreatment MRI images of each lesion. In the training set, a radiomics signature was constructed using the least absolute shrinkage and selection operator algorithm. Multivariable logistic regression analysis was then used to develop a radiomics model incorporated in the radiomics signature and independent clinical predictors. The performance of the model was assessed by its discrimination, calibration, and clinical usefulness with internal and external validation.

RESULTS

The radiomics signature consisted of 18 selected features and showed good discrimination performance. The model, which integrates the radiomics signature, the interval between radiotherapy and diagnosis of brain necrosis, and the interval between diagnosis of brain necrosis and treatment with bevacizumab, showed favorable calibration and discrimination in the training set (AUC 0.916). These findings were confirmed in the validation sets (AUC 0.912 and 0.827, respectively). Decision curve analysis confirmed the clinical utility of the model.

CONCLUSIONS

The presented radiomics model, available as an online calculator, can serve as a user-friendly tool for individualized prediction of the response to bevacizumab in patients with brain necrosis after radiotherapy.

Late effects of cancer treatment: consequences for long-term brain cancer survivors

Late adverse effects of cancer treatments represent a significant source of morbidity and also financial hardship among brain tumor patients. These effects can be produced by direct neurologic damage of the tumor and its removal, and/or by complementary treatments such as chemotherapy and radiotherapy, either alone or combined. Notably, young adults are the critical population that faces major consequences because the early onset of the disease may affect their development and socioeconomic status. The spectrum of these late adverse effects is large and involves multiple domains. In this review we classify the main long-term adverse effects into 4 sections: CNS complications, peripheral nervous system complications, secondary neoplasms, and Economic impact. In addition, CNS main complications are divided into nonfocal and focal symptoms. Owing to all the secondary effects mentioned, it is essential for physicians to have a high level of clinical suspicion to prevent and provide early intervention to minimize their impact.

Clinical Experience of Bevacizumab for Radiation Necrosis in Patients with Brain Metastasis

Background

As the application of radiotherapy to brain metastasis (BM) increases, the incidence of radiation necrosis (RN) as a late toxicity of radiotherapy also increases. However, no specific treatment for RN is indicated except long-term steroids. Here, we summarize the clinical results of bevacizumab (BEV) for RN.

Methods

Ten patients with RN who were treated with BEV monotherapy (7 mg/kg) were retrospectively reviewed. RN diagnosis was made using MRI with or without perfusion MRI. Radiological response was based on Response Assessment in Neuro-Oncology criteria for BM. The initial response was observed after 2 cycles every 2 weeks, and maintenance observed after 3 cycles every 3–6 weeks of increasing length intervals.

Results

The initial response of gadolinium (Gd) enhancement diameter maintained stable disease (SD) in 9 patients, and 1 patient showed partial response (PR). The initial fluid-attenuated inversion recovery (FLAIR) response showed PR in 4 patients and SD in 6 patients. The best radiological response was observed in 9 patients. Gd enhancement response was 6 PR and 3 SD between 15–43 weeks. Reduction of FLAIR showed PR in 5 patients and SD in 4 patients. Clinical improvement was observed in all but 1 patient. Five patients were maintained on protocol with durable response up to 23 cycles. However, 2 patients stopped treatment due to primary cancer progression, 1 patient received surgical removal from tumor recurrence, and 1 patient changed to systemic chemotherapy for new BM. Grade 3 intractable hypertension occurred in 1 patient who had already received antihypertensive medication.

Conclusion

BEV treatment for RN from BM radiotherapy resulted in favorable radiological (60%) and clinical responses (90%). Side effects were expectable and controllable. We anticipate prospective clinical trials to verify the effect of BEV monotherapy for RN.

The controversial role of Bevacizumab in the treatment of patients with intracranial meningioma: a comprehensive literature review

Introduction: Meningiomas represent the most common primary intracranial tumors. Today, surgical resection, followed by radiotherapy when indicated, is still the treatment of choice. In recent years, distinct oncogenic pathways have been identified, laying the foundations of new personalized targeted therapies.Areas covered: The aim of this study was to highlight the effects, complications, possible associations with other therapeutic approaches and multi-parametric outcome evaluation of Bevacizumab for the treatment of meningiomas. A literature review according to PRISMA criteria regarding the role of Bevacizumab for the treatment of various WHO grades of meningiomas was performed. 15 relevant papers, including 6 retrospective clinical trial series, 3 prospective trials, and 6 single patient case reports for a total of 134 patients and 211 meningiomas were include.Expert opinion: Because of the lack of strong clinical evidence about improved survival and related toxicity, the use of Bevacizumab for the treatment of meningiomas should be carefully evaluated. Further exploration, ideally with randomized controlled trials, is needed to better define the role of this drug in the treatment of meningiomas.

Hyperbaric Oxygen for Radiation Necrosis of the Brain

INTRODUCTION

Hyperbaric oxygen therapy (HBOT) shows promising results in treating radionecrosis (RN) but there is limited evidence for its use in brain RN. The purpose of this study is to report the outcomes of using HBOT for symptomatic brain RN at a single institution.

METHODS

This was a retrospective review of patients with symptomatic brain RN between 2008 and 2018 and was treated with HBOT. Demographic data, steroid use, clinical response, radiologic response and toxicities were collected. The index time for analysis was the first day of HBOT. The primary endpoint was clinical improvement of a presenting symptom, including steroid dose reduction.

RESULTS

Thirteen patients who received HBOT for symptomatic RN were included. The median time from last brain radiation therapy to presenting symptoms of brain RN was 6 months. Twelve patients (92%) had clinical improvement with median time to symptom improvement of 33 days (range 1-109 days). One patient had transient improvement after HBOT but had recurrent symptomatic RN at 12 months. Of the eight patients with evaluable follow-up MRI, four patients had radiological improvement while four had stable necrosis appearance. Two patients had subsequent deterioration in MRI appearances, one each in the background of initial radiologic improvement and stability. Median survival was 15 months with median follow-up of 10 months. Seven patients reported side effects attributable to HBOT (54%), four of which were otologic in origin.

CONCLUSIONS

HBOT is a safe and effective treatment for brain RN. HBOT showed clinical and radiologic improvement or stability in most patients. Prospective studies to further evaluate the effectiveness and side effects of HBOT are needed.

Effect of bevacizumab on brain radiation necrosis in anaplastic lymphoma kinase-positive lung cancer

Central nervous system (CNS) metastases from anaplastic lymphoma kinase (ALK)-positive lung cancer often results in failure of ALK-tyrosine kinase inhibitor (TKI) therapy. Patients with uncontrolled CNS metastases receive radiation therapy, which sometimes causes brain radiation necrosis. We added bevacizumab (15 mg/kg, every 3-4 weeks) to the regimen of four ALK-positive lung cancer patients with brain radiation necrosis who were receiving ALK-TKI therapy. A decrease in brain radiation necrosis was seen in all the patients, and an improvement in symptoms was seen in three patients. In one patient who was receiving corticosteroid therapy, we could taper the dose and subsequently discontinue it. While one patient discontinued bevacizumab because of adverse events, the other three continued with the treatment. Therefore, the combination of bevacizumab with ALK-TKI seems to be an effective, manageable, and tolerable treatment for brain radiation necrosis.

Bevacizumab treatment for radiation brain necrosis: mechanism, efficacy and issues

Vascular damage is followed by vascular endothelial growth factor (VEGF) expression at high levels, which is an important mechanism forradiation brain necrosis development. Bevacizumab alleviates brain edema symptoms caused by radiation brain necrosis through inhibiting VEGF and acting on vascular tissue around the brain necrosis area. Many studies have confirmed that bevacizumab effectively relieves symptoms caused by brain necrosis, improves patients' Karnofsky performance status (KPS) scores and brain necrosis imaging. However, necrosis is irreversible, and hypoxia and ischemia localized in the brain necrosis area may easily lead to radiation brain necrosis recurrence after bevacizumab is discontinued. Further studies are necessary to investigate brain necrosis diagnoses, bevacizumab indications, and the optimal mode of administration, bevacizumab resistance and necrosis with a residual or recurrent tumor.

Diagnosis and Management of Radiation Necrosis in Patients With Brain Metastases

The use of radiotherapy, either in the form of stereotactic radiosurgery (SRS) or whole-brain radiotherapy (WBRT), remains the cornerstone for the treatment of brain metastases (BM). As the survival of patients with BM is being prolonged, due to improved systemic therapy (i.e., for better extra-cranial control) and increased use of SRS (i.e., for improved intra-cranial control), patients are clinically manifesting late effects of radiotherapy. One of these late effects is radiation necrosis (RN). Unfortunately, symptomatic RN is notoriously hard to diagnose and manage. The features of RN overlap considerably with tumor recurrence, and misdiagnosing RN as tumor recurrence may lead to deleterious treatment which may cause detrimental effects to the patient. In this review, we will explore the pathophysiology of RN, risk factors for its development, and the strategies to evaluate and manage RN.

Brain Radiation Necrosis: Current Management With a Focus on Non-small Cell Lung Cancer Patients

As the prognosis of metastatic non-small cell lung cancer (NSCLC) patients is constantly improving with advances in systemic therapies (immune checkpoint blockers and new generation of targeted molecular compounds), more attention should be paid to the diagnosis and management of treatments-related long-term secondary effects. Brain metastases (BM) occur frequently in the natural history of NSCLC and stereotactic radiation therapy (SRT) is one of the main efficient local non-invasive therapeutic methods. However, SRT may have some disabling side effects. Brain radiation necrosis (RN) represents one of the main limiting toxicities, generally occurring from 6 months to several years after treatment. The diagnosis of RN itself may be quite challenging, as conventional imaging is frequently not able to differentiate RN from BM recurrence. Retrospective studies have suggested increased incidence rates of RN in NSCLC patients with oncogenic driver mutations [epidermal growth factor receptor (EGFR) mutated or anaplastic lymphoma kinase (ALK) positive] or receiving tyrosine kinase inhibitors. The risk of immune checkpoint inhibitors in contributing to RN remains controversial. Treatment modalities for RN have not been prospectively compared. Those include surveillance, corticosteroids, bevacizumab and local interventions (minimally invasive laser interstitial thermal ablation or surgery). The aim of this review is to describe and discuss possible RN management options in the light of the newly available literature, with a particular focus on NSCLC patients.

Interventions for the treatment of brain radionecrosis after radiotherapy or radiosurgery

BACKGROUND

Brain radionecrosis (tissue death caused by radiation) can occur following high-dose radiotherapy to brain tissue and can have a significant impact on a person's quality of life (QoL) and function. The underlying pathophysiological mechanism remains unclear for this condition, which makes establishing effective treatments challenging.

OBJECTIVES

To assess the effectiveness of interventions used for the treatment of brain radionecrosis in adults over 18 years old.

SEARCH METHODS

In October 2017, we searched the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, Embase and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for eligible studies. We also searched unpublished data through Physicians Data Query, www.controlled-trials.com/rct, www.clinicaltrials.gov, and www.cancer.gov/clinicaltrials for ongoing trials and handsearched relevant conference material.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of any intervention directed to treat brain radionecrosis in adults over 18 years old previously treated with radiation therapy to the brain. We anticipated a limited number of RCTs, so we also planned to include all comparative prospective intervention trials and quasi-randomised trials of interventions for brain radionecrosis in adults as long as these studies had a comparison group that reflects the standard of care (i.e. placebo or corticosteroids). Selection bias was likely to be an issue in all the included non-randomised studies therefore results are interpreted with caution.

DATA COLLECTION AND ANALYSIS

Two review authors (CC, PB) independently extracted data from selected studies and completed a 'Risk of bias' assessment. For dichotomous outcomes, the odds ratio (OR) for the outcome of interest was reported. For continuous outcomes, treatment effect was reported as mean difference (MD) between treatment arms with 95% confidence intervals (CIs).

MAIN RESULTS

Two RCTs and one prospective non-randomised study evaluating pharmacological interventions met the inclusion criteria for this review. As each study evaluated a different drug or intervention using different endpoints, a meta-analysis was not possible. There were no trials of non-pharmacological interventions that met the inclusion criteria.A very small randomised, double-blind, placebo-controlled trial of bevacizumab versus placebo reported that 100% (7/7) of participants on bevacizumab had reduction in brain oedema by at least 25% and reduction in post-gadolinium enhancement, whereas all those receiving placebo had clinical or radiological worsening or both. This was an encouraging finding but due to the small sample size we did not report a relative effect. The authors also failed to provide adequate details regarding the randomisation and blinding procedures Therefore, the certainty of this evidence is low and a larger RCT adhering to reporting standards is needed.An open-label RCT demonstrated a greater reduction in brain oedema (T2 hyperintensity) in the edaravone plus corticosteroid group than in the corticosteroid alone group (MD was 3.03 (95% CI 0.14 to 5.92; low-certainty evidence due to high risk of bias and imprecision); although the result approached borderline significance, there was no evidence of any important difference in the reduction in post-gadolinium enhancement between arms (MD = 0.47, 95% CI - 0.80 to 1.74; low-certainty evidence due to high risk of bias and imprecision).In the RCT of bevacizumab versus placebo, all seven participants receiving bevacizumab were reported to have neurological improvement, whereas five of seven participants on placebo had neurological worsening (very low-certainty evidence due to small sample size and concerns over validity of analyses). While no adverse events were noted with placebo, three severe adverse events were noted with bevacizumab, which included aspiration pneumonia, pulmonary embolus and superior sagittal sinus thrombosis. In the RCT of corticosteroids with or without edaravone, the participants who received the combination treatment were noted to have significantly greater clinical improvement than corticosteroids alone based on LENT/SOMA scale (OR = 2.51, 95% CI 1.26 to 5.01; low-certainty evidence due to open-label design). No differences in treatment toxicities were observed between arms.One included prospective non-randomised study of alpha-tocopherol (vitamin E) versus no active treatment was found but it did not include any radiological assessment. As only one included study was a double-blinded randomised controlled trial, the other studies were prone to selection and detection biases.None of the included studies reported quality of life outcomes or adequately reported details about corticosteroid requirements.A limited number of prospective studies were identified but subsequently excluded as these studies had a limited number of participants evaluating different pharmacological interventions using variable endpoints.

AUTHORS' CONCLUSIONS

There is a lack of good certainty evidence to help quantify the risks and benefits of interventions for the treatment of brain radionecrosis after radiotherapy or radiosurgery. In an RCT of 14 patients, bevacizumab showed radiological response which was associated with minimal improvement in cognition or symptom severity. Although it was a randomised trial by design, the small sample size limits the quality of data. A trial of edaravone plus corticosteroids versus corticosteroids alone reported greater reduction in the surrounding oedema with combination treatment but no effect on the enhancing radionecrosis lesion. Due to the open-label design and wide confidence intervals in the results, the quality of this data was also low. There was no evidence to support any non-pharmacological interventions for the treatment of radionecrosis. Further prospective randomised studies of pharmacological and non-pharmacological interventions are needed to generate stronger evidence. Two ongoing RCTs, one evaluating bevacizumab and one evaluating hyperbaric oxygen therapy were identified.

Bevacizumab as an effective treatment for radiation necrosis after radiotherapy for melanoma brain metastases

Radiation necrosis (RN) is a potential late complication of radiotherapy for intracranial malignancy, which is often associated with significant neurological morbidity. Prolonged treatment with high-dose corticosteroids or surgical resection has been the standard care for RN, but protracted steroid use can lead to significant side effects and surgical resection is not always feasible. The antivascular endothelial growth factor monoclonal antibody bevacizumab induces clinical and radiographic improvements in RN, with overall good tolerance. However, evidence supporting its use for RN in melanoma brain metastases is minimal, likely secondary to concern for intracranial bleeding. Immunotherapy is now one of the most commonly used and effective therapies for metastatic melanoma. A higher risk of RN has been reported with immunotherapy, making alternative treatment for RN in this population a priority, especially as prolonged use of steroids may counteract the treatment efficacy of immunotherapy. We report on seven melanoma patients who developed RN after stereotactic radiosurgery with or without whole-brain radiation therapy who were treated with 2-6 doses of bevacizumab. All patients experienced improvements in symptoms and quality of life, with a concurrent improvement in imaging in six patients. Furthermore, bevacizumab was well tolerated and none of the seven patients experienced intracranial or extracranial bleeding. Our series suggests that in selected melanoma brain metastases patients, bevacizumab may be a safe and effective treatment for RN, especially for those who are undergoing immunotherapy, and should be further evaluated in a prospective setting.

Bevacizumab Monotherapy Reduces Radiation-induced Brain Necrosis in Nasopharyngeal Carcinoma Patients: A Randomized Controlled Trial

PURPOSE

Studies have shown that addition of bevacizumab to corticosteroids improves outcome against radiation-induced brain necrosis (RN). Here, we aimed to evaluate the effectiveness and safety of bevacizumab monotherapy on RN in nasopharyngeal carcinoma (NPC) patients.

METHODS AND MATERIALS

In this multicenter open-label study, patients with RN were randomly assigned (1:1) into a bevacizumab group (5 mg/kg intravenously every 2 weeks, for 4 cycles) or a corticosteroid group (methylprednisolone 500 mg/day intravenously for 3 consecutive days and then gradually tapered, followed by 10 mg/day oral prednisone, for 2 months in total). Magnetic resonance imaging (MRI) was performed pre- and post-treatment to define the radiographic response. The primary outcome was a 2-month response rate as determined by MRI and clinical symptoms. All of the patients were followed up with for 6 months. The trial was registered at www.clinicaltrials.gov (NCT01621880).

RESULTS

Of 121 patients screened, 112 patients met the entry criteria. Thirty-eight (65.5%) patients in the bevacizumab group showed response, which was significantly higher than that in the corticosteroid group (65.5% vs 31.5%, P < .001). The mean percentage decrease in RN volume seen on T1 post-gadolinium and T2-weighted fluid-attenuated inversion recovery (FLAIR) MRI was 25.5% and 51.8%, respectively, in the bevacizumab group, versus 5.0% and 19.3%, respectively, in the corticosteroid group. Moreover, 36 patients (62.1%) on bevacizumab and 23 patients (42.6%) on corticosteroids demonstrated clinical improvement (P = .039). During the 6-month follow up, fourteen patients on bevacizumab and 13 patients on corticosteroids showed RN recurrence. The most frequent adverse event in the bevacizumab group was hypertension (20.6%).

CONCLUSIONS

Our study indicate that compared with corticosteroids, bevacizumab offers improved symptomatic relief and radiographic response.

Neuro-oncologists have spoken - the role of bevacizumab in the inpatient setting. A clinical and economic conundrum

Background

Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor (VEGF), a key player in tumor angiogenesis. The drug can halt tumor progression, treat radiation necrosis, and reduce peritumoral edema. Although it does not increase overall survival, bevacizumab can improve progression-free survival and quality of life. In many countries, bevacizumab use in the inpatient setting is restricted due to its significant cost. Here, we explore attitudes towards the use of bevacizumab amidst practitioners treating brain tumors and assess ease of accessing the drug in the inpatient setting.

Design/Methods

A 10-question survey querying practitioners' opinions of inpatient bevacizumab utility and its availability was distributed to the membership of the Society of Neuro-Oncology in July 2016.

Results

Eighty-seven percent felt that there was a role for bevacizumab in the inpatient setting, and 69% reported favorable experiences with bevacizumab use. However, 40% encountered difficulty in obtaining approval for inpatient use. We present two contrasting clinical cases that highlight favorable and unfavorable outcomes when bevacizumab use was and was not permitted, respectively.

Conclusions

In this sample of neuro-oncology practitioners, there is general consensus that bevacizumab plays an important role in the inpatient treatment of brain tumors. In light of ongoing barriers to inpatient bevacizumab use due to cost concerns, these data motivate the creation of standardized policies for inpatient bevacizumab use that balances its important role in improving quality of life with financial considerations.

Primary intracranial leiomyosarcoma in an immunocompetent patient: Case report and review of the literature

Primary leiomyosarcoma is a rare tumor in the CNS, with few reported cases. Here, we describe a case of a primary intracranial leiomyosarcoma of the tentorium cerebelli. A 43-year-old woman presented with headache, acute vision loss, and difficulty speaking. MRI revealed a large heterogeneous-enhancing occipital mass, which was subsequently resected and diagnosed as a primary intracranial leiomyosarcoma. The patient went onto adjuvant radiotherapy delivering 60 Gy in 30 fractions. These tumors are exceedingly rare in immunocompetent individuals. We reviewed the 16 cases that have been reported in the literature. Surgical resection was the most common treatment (92%) with 53% receiving adjuvant radiation. There currently is no standard treatment regimen for intracranial leiomyosarcomas. Additional case reports that include descriptive treatment approaches with patient outcomes may help ascertain the best approach to treating these malignancies.

Inhibitors of HIF-1α and CXCR4 Mitigate the Development of Radiation Necrosis in Mouse Brain

PURPOSE

There is mounting evidence that, in addition to angiogenesis, hypoxia-induced inflammation via the hypoxia-inducible factor 1α (HIF-1α)-CXC chemokine receptor 4 (CXCR4) pathway may contribute to the pathogenesis of late-onset, irradiation-induced necrosis. This study investigates the mitigative efficacy of an HIF-1α inhibitor, topotecan, and a CXCR4 antagonist, AMD3100, on the development of radiation necrosis (RN) in an intracranial mouse model.

METHODS AND MATERIALS

Mice received a single-fraction, 50-Gy dose of hemispheric irradiation from the Leksell Gamma Knife Perfexion and were then treated with either topotecan, an HIF-1α inhibitor, from 1 to 12 weeks after irradiation, or AMD3100, a CXCR4 antagonist, from 4 to 12 weeks after irradiation. The onset and progression of RN were monitored longitudinally via noninvasive, in vivo magnetic resonance imaging (MRI) from 4 to 12 weeks after irradiation. Conventional hematoxylin-eosin staining and immunohistochemistry staining were performed to evaluate the treatment response.

RESULTS

The progression of brain RN was significantly mitigated for mice treated with either topotecan or AMD3100 compared with control animals. MRI-derived lesion volumes were significantly smaller for both of the treated groups, and histologic findings correlated well with the MRI data. By hematoxylin-eosin staining, both treated groups demonstrated reduced irradiation-induced tissue damage compared with controls. Furthermore, immunohistochemistry results revealed that expression levels of vascular endothelial growth factor, CXC chemokine ligand 12, CD68, CD3, and tumor necrosis factor α in the lesion area were significantly lower in treated (topotecan or AMD3100) brains versus control brains, while ionized calcium-binding adapter molecule 1 (Iba1) and HIF-1α expression was similar, though somewhat reduced. CXCR4 expression was reduced only in topotecan-treated mice, while interleukin 6 expression was unaffected by either topotecan or AMD3100.

CONCLUSIONS

By reducing inflammation, both topotecan and AMD3100 can, independently, mitigate the development of RN in the mouse brain. When combined with first-line, antiangiogenic treatment, anti-inflammation therapy may provide an adjuvant therapeutic strategy for clinical, postirradiation management of tumors, with additional benefits in the mitigation of RN development.

Factors Associated with Occurrence of Radiation-induced Optic Neuropathy at "Safe" Radiation Dosage

BACKGROUND

Radiation-induced optic neuropathy (RION) is a rare, and often visually devastating, complication of radiation therapy (RT) near the anterior visual pathways.

METHODS

A retrospective case series of patients who developed RION at a tertiary medical center, followed by a case-control study comparing RION cases with matched controls who received RT.

RESULTS

Thirteen patients (18 eyes) with RION were identified. Radiation modalities included external beam photon radiation, whole brain radiation, stereotactic radiosurgery, proton beam, and unknown. Most patients received doses below published "safe" thresholds (<55 Gy; <8-10 Gy for stereotactic radiosurgery). There was no statistically significant difference in prevalence of vasculopathic factors between cases and controls; on subgroup analysis in three patients who received surprisingly low radiation doses, smoking (p=0.05) and hypertension (p=0.02) appeared more prevalent.

CONCLUSION

RION can occur at doses below published "safe" thresholds and with different RT modalities. Smoking and hypertension might be risk factors for RION.

Bevacizumab for the Treatment of Radiation-Induced Cerebral Necrosis: A Systematic Review of the Literature

Radiation necrosis (RN) of brain tissue is a serious late complication of brain irradiation and recently bevacizumab has been suggested as treatment option of RN. There is a lack of data in the literature regarding the effectiveness of bevacizumab for the treatment of RN. The purpose of this review was to perform a comprehensive analysis of all reported cases using bevacizumab for the treatment of brain RN. In September 2016, we performed a comprehensive literature search of the following electronic databases: PubMed, Web of Science, Scopus and Cochrane Library. The research for the review was conducted using a combination of the keywords "radiation necrosis", "radiotherapy" and "bevacizumab" alongside the fields comprising article title, abstract and keywords. Randomized trials, non-randomized trials, prospective studies, retrospective studies and single case reports were included in the review. Our research generated 21 studies and 125 cases where bevacizumab had been used for the treatment of RN. The median follow-up was 8 months and the most frequent bevacizumab dose used was 7.5 mg/kg for 2 weeks with a median of four cycles. Low-dose bevacizumab resulted in effectiveness with improvement in both clinical and radiographic response. The median decrease in T1 contrast enhancement and in T2/FLAIR signal abnormality was 64% and 60%, respectively. A reduction in steroidal therapy was observed in majority of patients treated. Based on the data of our review, bevacizumab appears to be a promising agent for the treatment of brain RN. Future prospective studies are required to evaluate the role of bevacizumab in RN and to define the optimal scheduling, dosage and duration of therapy.

Bevacizumab for Treatment-Refractory Pain Control in Neurofibromatosis Patients

OBJECTIVE

Chronic pain is a well-known morbidity associated with neurofibromatosis (NF) for which better therapies are needed. Surgery, radiation, and pain medications have been utilized, but often fail to relieve debilitating pain. One patient at our institution was noted to have near complete resolution of pain after treatment with bevacizumab for progressive neurologic deficit associated with NF2, suggesting its potential as an effective pain control method. We aim to better characterize the use of bevacizumab for pain control in this subset of patients.  Patients and Methods: We retrospectively reviewed 38 NF patients treated at our institution.   Results: Of the 38 total NF patients, we found that 63% reported chronic pain, with 18% reporting chronic opiate usage. Nine patients with chronic pain were considered for bevacizumab treatment and five went on to receive infusions. Of these patients, four out of five had previous surgical debulking and two out of five had previous radiation for attempted pain control. One patient had a lesion not amenable to surgery or radiation. Patients received a median of 13 cycles of bevacizumab, and four out of five patients reported a decrease in subjective pain. All patients that had pain relief had a relapse of pain symptoms when the dose was reduced or infusions were paused. Seventy-five percent were able to decrease opiate use. No major complications were noted. All five patients have elected to continue infusions for pain control.  Conclusion: Bevacizumab was, in general, well tolerated and should be considered as a treatment option in NF patients with chronic pain refractory or not amenable to surgical decompression and debulking, radiation, and pain medication.

Activity and safety of radiotherapy with anti-PD-1 drug therapy in patients with metastatic melanoma

The anti-PD-1 antibodies nivolumab and pembrolizumab are active in metastatic melanoma; however, there is limited data on combining anti-PD-1 antibody and radiotherapy (RT). We sought to review clinical outcomes of patients receiving RT and anti-PD-1 therapy. All patients receiving anti-PD-1 antibody and RT for metastatic melanoma were identified. RT and systemic treatment, clinical outcome, and toxicity data were collected. Fifty-three patients were included; 35 patients received extracranial RT and/or intracranial stereotactic radiosurgery (SRS) and 21 received whole brain radiotherapy (WBRT) (three of whom also received SRS/extracranial RT). Patients treated with extracranial RT or SRS received treatment either sequentially (RT then anti-PD-1, n = 11), concurrently (n = 16), or concurrent "salvage" treatment to lesions progressing on anti-PD-1 therapy (n = 15). There was no excessive anti-PD-1 or RT toxicity observed in patients receiving extracranial RT. Of six patients receiving SRS, one patient developed grade 3 radiation necrosis. In 21 patients receiving WBRT, one patient developed Stevens-Johnson syndrome, one patient developed acute neurocognitive decline, and one patient developed significant cerebral edema in the setting of disease. Response in irradiated extracranial/intracranial SRS lesions was 44% for sequential treatment and 64% for concurrent treatment (p=0.448). Likewise there was no significant difference between sequential or concurrent treatment in lesional response of non-irradiated lesions. For progressing lesions subsequently irradiated, response rate was 45%. RT and anti-PD-1 antibodies can be safely combined, with no detectable excess toxicity in extracranial sites. WBRT and anti-PD-1 therapy is well tolerated, although there are rare toxicities and the role of either anti-PD-1 or WBRT in the etiology of these is uncertain.