Salvage stereotactic radiosurgery with adjuvant use of bevacizumab for heavily treated recurrent brain metastases: a preliminary report

Long-term impact of bevacizumab for the treatment of brain radiation necrosis

PURPOSE

To evaluate short and long-term efficacy of bevacizumab (Bev), for the treatment of radiation necrosis (RN) in patients with brain metastasis after stereotactic radiosurgery (SRS).

METHODS

The database of a tertiary medical center was reviewed for all adult patients treated by Bev (from January 2018 to January 2023) for RN after having received SRS for BM. Clinical and MRI data were systematically collected at baseline, immediately after the completion of Bev treatment, and at 6, 12, and, when available, 24 months post-treatment.

RESULTS

The cohort included 23 patients with a total of 31 RN lesions (defined as target lesion) which have been previously treated by SRS, either as single-session SRS (27/31) or as fractionated stereotactic radiotherapy (4/31). Median follow-up time was 15 months (range: 8-28.5). Immediately after completion of Bev, 15 patients (65.2%) exhibited a complete/partial response, 6 (26.1%) had stable disease, and 2 had progressive disease (8.7%). thirteen patients (56%) improved clinically. Greater than 50% reduction in volume was observed in 84% of target lesions. At 12 months, among the 13 patients still evaluable (9 other being deceased, 1 loss to follow up), three continued to improve, and four remained stable. Median volume of target lesion was then 1.4 cm3 (range 0.7-2.9) demonstrating a reduction of 67.4% compared to the initial target volume, which was 4.35 cm3 (range 2.14-10.37). During the entire follow-up period, 11 patients experienced regrowth of the target lesion; median time to progression was 7 months. Five underwent Bev re-challenge, but only 2 responded.

CONCLUSION

Bev for the treatment of SRS-induced RN was associated with a high initial response rate, significant lesion reduction, and prolonged clinical improvement. However, the high rate of lesion regrowth (50%) and poor response to Bev re-challenge highlight the complexity of diagnosis and treatment of RN.

Stereotactic Radiosurgery as Treatment for Brain Metastases: An Update

Stereotactic radiosurgery (SRS) is a mainstay treatment option for brain metastasis (BM). While guidelines for SRS use have been outlined by professional societies, consideration of these guidelines should be weighed in the context of emerging literature, novel technology platforms, and contemporary treatment paradigms. Here, we review recent advances in prognostic scale development for SRS-treated BM patients and survival outcomes as a function of the number of BM and cumulative intracranial tumor volume. Focus is placed on the role of stereotactic laser thermal ablation in the management of BM that recur after SRS and the management of radiation necrosis. Neoadjuvant SRS prior to surgical resection as a means of minimizing leptomeningeal spread is also discussed.

Stereotactic radiosurgery with whole brain radiotherapy combined with bevacizumab in the treatment of brain metastases from NSCLC

OBJECTIVE

Non-small cell lung cancer (NSCLC) patients who experience brain metastases are usually associated with poor prognostic outcomes. Whole-brain radiotherapy (WBRT) is one of the standard treatment strategies for NSCLC. It is interesting to combine angiogenesis inhibitors such as bevacizumab with radiation therapy. This study aimed to explore the efficacy and safety of stereotactic radiosurgery (SRS) with WBRT combined with bevacizumab in the treatment of brain metastases.

METHODS

A total of 21 patients with brain metastases from NSCLC were treated with bevacizumab and WBRT-SRS, while 28 patients were treated with WBRT-SRS only. The bevacizumab average dose was 5-7.5 mg/kg, approximately 2 cycles during radiotherapy. Tumor responses were evaluated every 3 months based on Response Evaluation Criteria in Solid Tumors version 1.1.

RESULTS

The median follow-up time was 13.5 months (range 2.7-88.4 months). The ORR and DCR of patients who received WBRT-SRS with or without bevacizumab were similar (p = 0.458, p = 0.382). OS(42.63 years VS 25.23 years, p = 0.02)and LPFS (39.53 years VS 23 years, p = 0.047)were better in WBRT-SRS with bevacizumab groups. After radiotherapy and 3 months after radiotherapy, the volume of peritumoral edema was significantly reduced in WBRT-SRS with bevacizumab groups(45.62 ± 24.03 cm³ vs 63.03 ± 25.44 cm³, p = 0.036;8.63 ± 6.87 cm³ vs 15.62 ± 10.58 cm³, p = 0.021). The main adverse reactions were similar in the two groups except for Venous thrombosis with bevacizumab (0 patients vs 5 patients, p = 0.006).

CONCLUSION

Bevacizumab with radiotherapy improved the overall efficacy and reduced the peritumoral edema of BM from NSCLC.

Integrating stereotactic radiotherapy and systemic therapies

This paper focuses on stereotactic radiotherapy (SRT ) interactions with targeted therapies and immune system modulating agents because SRT inevitably interacts with them in the treatment of oligometastatic patients. Radiation oncologists need to be aware of the advantages and risks of these interactions which can, on one hand, enhance the effect of therapy or, on the other, potentiate reciprocal toxicities. To date, few prospective studies have evaluated the interactions of SRT with new-generation drugs and data are mainly based on retrospective experiences, which are often related to small sample sizes.

Efficacy and Safety of a Second Course of Stereotactic Radiation Therapy for Locally Recurrent Brain Metastases: A Systematic Review

Recent advances in cancer treatments have increased overall survival and consequently, local failures (LFs) after stereotactic radiotherapy/radiosurgery (SRS/SRT) have become more frequent. LF following SRS or SRT may be treated with a second course of SRS (SRS2) or SRT (SRT2). However, there is no consensus on whenever to consider reirradiation. A literature search was conducted according to PRISMA guidelines. Analysis included 13 studies: 329 patients (388 metastases) with a SRS2 and 135 patients (161 metastases) with a SRT2. The 1-year local control rate ranged from 46.5% to 88.3%. Factors leading to poorer LC were histology (melanoma) and lack of prior whole-brain radiation therapy, large tumor size and lower dose at SRS2/SRT2, poorer response at first SRS/SRT, poorer performance status, and no controlled extracranial disease. The rate of radionecrosis (RN) ranged from 2% to 36%. Patients who had a large tumor volume, higher dose and higher value of prescription isodose line at SRS2/SRT2, and large overlap between brain volume irradiated at SRS1/SRT1 and SRS2/SRT2 at doses of 18 and 12 Gy had a higher risk of developing RN. Prospective studies involving a larger number of patients are still needed to determine the best management of patients with local recurrence of brain metastases.

Integration of Systemic Therapy and Stereotactic Radiosurgery for Brain Metastases

Simple Summary

In the multi-modal treatment of brain metastasis (BM), the role of systemic therapy has undergone a recent revolution. Due to the development of multiple agents with modest central nervous system penetration of the blood-brain barrier, targeted therapies and immune checkpoint inhibitors are increasingly being utilized alone or in combination with radiation therapy. However, the adoption of sequential or concurrent strategies varies considerably, and treatment strategies employed in clinical practice have rapidly outpaced evidence development. Therefore, this review critically analyzes the data regarding combinatorial approaches for a variety of systemic therapeutics with stereotactic radiosurgery and provides an overview of ongoing clinical trials.

Abstract

Brain metastasis (BM) represents a common complication of cancer, and in the modern era requires multi-modal management approaches and multi-disciplinary care. Traditionally, due to the limited efficacy of cytotoxic chemotherapy, treatment strategies are focused on local treatments alone, such as whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), and resection. However, the increased availability of molecular-based therapies with central nervous system (CNS) penetration now permits the individualized selection of tailored systemic therapies to be used alongside local treatments. Moreover, the introduction of immune checkpoint inhibitors (ICIs), with demonstrated CNS activity has further revolutionized the management of BM patients. The rapid introduction of these cancer therapeutics into clinical practice, however, has led to a significant dearth in the published literature about the optimal timing, sequencing, and combination of these systemic therapies along with SRS. This manuscript reviews the impact of tumor biology and molecular profiles on the management paradigm for BM patients and critically analyzes the current landscape of SRS, with a specific focus on integration with systemic therapy. We also discuss emerging treatment strategies combining SRS and ICIs, the impact of timing and the sequencing of these therapies around SRS, the effect of corticosteroids, and review post-treatment imaging findings, including pseudo-progression and radiation necrosis.

Bevacizumab vs laser interstitial thermal therapy in cerebral radiation necrosis from brain metastases: a systematic review and meta-analysis

PURPOSE

Radiation necrosis (RN) represents a serious post-radiotherapy complication in patients with brain metastases. Bevacizumab and laser interstitial thermal therapy (LITT) are viable treatment options, but direct comparative data is scarce. We reviewed the literature to compare the two treatment strategies.

METHODS

PubMed, EMBASE, Scopus, and Cochrane databases were searched. All studies of patients with RN from brain metastases treated with bevacizumab or LITT were included. Treatment outcomes were analyzed using indirect meta-analysis with random-effect modeling.

RESULTS

Among the 18 studies included, 143 patients received bevacizumab and 148 underwent LITT. Both strategies were equally effective in providing post-treatment symptomatic improvement (P = 0.187, I² = 54.8%), weaning off steroids (P = 0.614, I² = 25.5%), and local lesion control (P = 0.5, I² = 0%). Mean number of lesions per patient was not statistically significant among groups (P = 0.624). Similarly, mean T1-contrast-enhancing pre-treatment volumes were not statistically different (P = 0.582). Patterns of radiological responses differed at 6-month follow-ups, with rates of partial regression significantly higher in the bevacizumab group (P = 0.001, I² = 88.9%), and stable disease significantly higher in the LITT group (P = 0.002, I² = 81.9%). Survival rates were superior in the LITT cohort, and statistical significance was reached at 18 months (P = 0.038, I² = 73.7%). Low rates of adverse events were reported in both groups (14.7% for bevacizumab and 12.2% for LITT).

CONCLUSION

Bevacizumab and LITT can be safe and effective treatments for RN from brain metastases. Clinical and radiological outcomes are mostly comparable, but LITT may relate with superior survival benefits in select patients. Further studies are required to identify the best patient candidates for each treatment group.

Peri-radiosurgical administration of bevacizumab improves radiographic response to single and fractionated stereotactic radiosurgery for large brain metastasis

INTRODUCTION

Stereotactic radiosurgery (SRS) is a standard of care for brain metastases (BM) patients, yet large BM are at a greater risk for radionecrosis and local progression (LP). Concomitant bevacizumab and radiotherapy has been shown to improve outcomes in primary and metastatic brain tumors. This retrospective study investigated the efficacy and safety of concurrent bevacizumab and SRS for large BM.

METHODS

From 2015 to 2019, patients with a BM diameter ≥ 2 cm who received either combination therapy (n = 49, SRS + BVZ group), or SRS alone (n = 73, SRS group) were enrolled. Bevacizumab was given peri-radiosurgically with a 2-week interval. Radiographic response was assessed using the RECIST version 1.1. Competing risk and logistic regression analysis were performed to evaluate prognostic factors.

RESULTS

Radiographic response was achieved in 41 patients (84%) in the SRS + BVZ group and 37 patients (51%) in the SRS group (p = 0.001). In the multivariate regression analysis, concurrent bevacizumab was independently associated with a better radiographic response (p = 0.003). The cumulative incidences of LP and ≥ grade 2 radionecrosis at 12 months between the SRS + BVZ group and SRS group were 2% versus 6.8%, and 14.3% versus 14.6%, respectively. For patients with BM size ≥ 3 cm, the cumulative incidence of LP was significantly lower in the SRS + BVZ group (p = 0.03). No ≥ grade 4 toxicity was observed in either group.

CONCLUSIONS

Concurrent bevacizumab and SRS for large BM is highly effective, with a better radiographic response and minimal excessive treatment-related toxicities. Peri-radiosurgical bevacizumab preferentially reduced the risk of LP, especially for BM size ≥ 3 cm.

Concurrent Apatinib and Brain Radiotherapy in Patients With Brain Metastases From Driver Mutation-negative Non-small-cell Lung Cancer: Study Protocol for an Open-label Randomized Controlled Trial

Brain radiotherapy (BR) is a well-recognized approach for multiple brain metastases (BMs) from non-small-cell lung cancer (NSCLC). However, the prognosis for these patients remains poor. Apatinib, an antiangiogenic agent targeting vascular endothelial growth factor receptor-2, has shown excellent efficacy in multiple solid tumors. This phase II (WWW. ClinicalTrials.gov Identifier: VEGFR-2 NCT03801200) randomized trial aims to evaluate the efficacy and safety of this combined modality paradigm in patients with BMs from driver mutation-negative NSCLC. This is a multicenter, open-label, randomized controlled clinical trial. A total of 90 eligible patients will be allocated in a 1:1 ratio, to either the experimental group (concurrent apatinib and BR) or the control group (BR alone). The primary endpoint is intracranial progression-free survival. The secondary endpoints include intracranial objective response rate, intracranial disease control rate, intracranial time to progression, overall survival, and occurrence of peritumoral brain edema using standardized measurement. Quality of life and adverse events will also be evaluated. Assessments will be carried out before enrollment (baseline) along with 4 and 12 weeks after radiotherapy, followed by every 12 weeks thereafter and up to 24 months. In summary, the aim of this trial is to demonstrate the clinical efficacy and safety of concurrent BR and apatinib in patients with driver mutation-negative NSCLC with multiple BMs, in efforts to expand management options for this population with poor prognosis.

Safety and efficacy of Hypofractionated stereotactic radiosurgery for high-grade Gliomas at first recurrence: a single-center experience

Background

The optimal treatment for recurrent high-grade gliomas (rHGGs) remains uncertain. This study aimed to investigate the efficacy and safety of hypofractionated stereotactic radiosurgery (HSRS) as a first-line salvage treatment for in-field recurrence of high-grade gliomas.

Methods

Between January 2016 and October 2019, 70 patients with rHGG who underwent HSRS were retrospectively analysed. The primary endpoint was overall survival (OS), and secondary endpoints included both progression-free survival (PFS) and adverse events, which were assessed according to Common Toxicity Criteria Adverse Events (CTCAE) version 5. The prognostic value of key clinical features (age, performance status, planning target volume, dose, use of bevacizumab) was evaluated.

Results

A total of 70 patients were included in the study. Forty patients were male and 30 were female. Forty-nine had an initial diagnosis of glioblastoma (GBM), and the rest (21) were confirmed to be WHO grade 3 gliomas. The median planning target volume (PTV) was 16.68 cm³ (0.81–121.96 cm³). The median prescribed dose was 24 Gy (12–30 Gy) in 4 fractions (2–6 fractions). The median baseline of Karnofsky Performance Status (KPS) was 70 (40–90). With a median follow-up of 12.1 months, the median overall survival after salvage treatment was 17.6 months (19.5 and 14.6 months for grade 3 and 4 gliomas, respectively; p = .039). No grade 3 or higher toxicities was recorded. Multivariate analysis showed that concurrent bevacizumab with radiosurgery and KPS > 70 were favourable prognostic factors for grade 4 patients with HGG.

Conclusions

Salvage HSRS showed a favourable outcome and acceptable toxicity for rHGG. A prospective phase II study (NCT04197492) is ongoing to further investigate the value of hypofractionated stereotactic radiosurgery (HSRS) in rHGG.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07856-y.

Safety of radiosurgery concurrent with systemic therapy (chemotherapy, targeted therapy, and/or immunotherapy) in brain metastases: a systematic review

Stereotactic radiosurgery (SRS) is a standard option for brain metastases (BM). There is lack of consensus when patients have a systemic treatment, if a washout is necessary. The aim of this review is to analyze the toxicity of SRS when it is concurrent with chemotherapies, immunotherapy, and/or targeted therapies. From Medline and Embase databases, we searched for English literature published up to April 2020 according to the PRISMA guidelines, using for key words the list of the main systemic therapies currently in use And "radiosurgery," "SRS," "GKRS," "Gamma Knife," "toxicity," "ARE," "radiation necrosis," "safety," "brain metastases." Studies reporting safety or toxicity with SRS concurrent with systemic treatment for BM were included. Of 852 abstracts recorded, 77 were included. The main cancers were melanoma, lung, breast, and renal carcinoma. These studies cumulate 6384 patients. The median SRS dose prescription was 20 Gy [12-30] .For some, they compared a concurrent arm with a non-concurrent or a SRS-alone arm. There were no skin toxicities, no clearly increased rate of bleeding, or radiation necrosis with significant clinical impact. SRS combined with systemic therapy appears to be safe, allowing the continuation of treatment when brain SRS is considered.

Single- versus 2-session Gamma Knife surgery for symptomatic midsize brain metastases: a propensity score-matched analysis

OBJECTIVE

Two-session Gamma Knife surgery (GKS) has recently been demonstrated to be an effective and less-invasive alternative for large brain metastases not treatable by microsurgical resection. This raises the clinical question of whether the 2-session GKS strategy further improves treatment outcomes for patients with symptomatic midsize brain metastases (2-10 cm3) as compared to single-session GKS. The present study aimed to compare the local therapeutic effects and toxicities of single-session and 2-session GKS for treating these lesions.

METHODS

Patients with focal neurological deficits attributable to midsize brain metastases who underwent upfront GKS during the period from 2010 to 2018 were retrospectively identified from an institutional database. Patients for whom both post-GKS imaging studies and neurological evaluations from outpatient visits were available were eligible. Using propensity score-matching (PSM) analysis, unique matched pairs which had a similar likelihood of receiving 2-session GKS were generated. The main outcome measure was a composite of imaging and/or neurological worsening of the lesion of interest. Functional improvement and overall survival (OS) were also compared between the 2 treatment arms.

RESULTS

In total, 219 cancer patients with 252 symptomatic midsize brain metastases were eligible. Of these 252 tumors, 176 and 76 were treated with single- and 2-session GKS, respectively. After PSM, 68 pairs of tumors were obtained. The Gray test showed that 2-session GKS achieved a longer local progression-free interval than single-session GKS (1-year local control rate: 84% vs 53%; HR 0.31, 95% CI 0.16-0.63, p = 0.001). Two-session GKS was also associated with greater functional improvement in KPS scores (mean 18.3 ± 14.6 vs 12.8 ± 14.1, p = 0.040). The median OS did not differ significantly between single- and 2-session GKS (15.6 vs 24.7 months; HR 0.69, 95% CI 0.44-1.10, p = 0.11).

CONCLUSIONS

Two-session GKS achieved more durable local tumor control and greater functional improvement than single-session GKS for patients with symptomatic midsize brain metastases, although there was no OS advantage.

Stereotactic reirradiation for local failure of brain metastases following previous radiosurgery: Systematic review and meta-analysis

INTRODUCTION

Local failure (LF) following stereotactic radiosurgery (SRS) of brain metastases (BM) may be treated with a second course of SRS (SRS2), though this procedure may increase the risk of symptomatic radionecrosis (RN).

METHODS

A literature search was conducted according to PRISMA to identify studies reporting LF, overall survival (OS) and RN rates following SRS2. Meta-analysis was performed to identify predictors of RN.

RESULTS

Analysis included 11 studies (335 patients,389 metastases). Pooled 1-year LF was 24 %(CI95 % 19-30 %): heterogeneity was acceptable (I2 = 21.4 %). Median pooled OS was 14 months (Confidence Interval 95 %, CI95 % 8.8-22.0 months). Cumulative crude RN rate was 13 % (95 %CI 8 %-19 %), with acceptable heterogeneity (I2 = 40.3 %). Subgroup analysis showed higher RN incidence in studies with median patient age ≥59 years (13 % [95 %CI 8 %-19 %] vs 7 %[95 %CI 3 %-12 %], p = 0.004) and lower incidence following prior Whole Brain Radiotherapy (WBRT, 19 %[95 %CI 13 %-25 %] vs 7%[95 %CI 3 %-13 %], p = 0.004).

CONCLUSIONS

SRS2 is an effective strategy for in-site recurrence of BM previously treated with SRS.

The Safety and Efficacy of Bevacizumab for Radiosurgery - Induced Steroid - Resistant Brain Edema; Not the Last Part in the Ship of Theseus

Background

Radiation-induced brain edema (RIBE) is a serious complication of radiation therapy. It may result in dramatic clinico-radiological deterioration. At present, there are no definite guidelines for management of the complication. Corticosteroids are the usual first line of treatment, which frequently fails to provide long-term efficacy in view of its adverse complication profile. Bevacizumab has been reported to show improvement in cases of steroid-resistant radiation injury. The objective of this study is to evaluate the role of Bevacizumab in post-radiosurgery RIBE.

Material and Methods

Since 2012, 189 out of 1241 patients who underwent radiosurgery at our institution developed post-radiosurgery RIBE, 17 of which did not respond to high-dose corticosteroids. We systematically reviewed these 17 patients of various intracranial pathologies with clinic-radiological evidence of RIBE following gamma knife radiosurgery (GKRS). All patients received protocol-based Bevacizumab therapy. The peer-reviewed literature was evaluated.

Results

82 percent of the patients showed improvement after starting Bevacizumab. The majority began to improve after the third cycle started improvement after the third cycle of Bevacizumab. Clinical improvement preceded radiological improvement by an average of eight weeks. The first dose was 5 mg/kg followed by 7.5-10 mg/kg at with two-week intervals. Bevacizumab needs to be administered for an average of seven cycles (range 5-27, median 7) for best response. Steroid therapy could be tapered in most patients by the first follow-up. One patient did not respond to Bevacizumab and needed surgical decompression for palliative care. One noncompliant patient died due to radiation injury.

Conclusion

Bevacizumab is a effective and safe for treatment of RIBE after GKRS. A protocol-based dose schedule in addition to frequent clinical and radiological evaluations are required. Bevacizumab should be considered as an early treatment option for RIBE.

Hypofractionated Radiosurgery Plus Bevacizumab for Locally Recurrent Brain Metastasis with Previously High-Dose Irradiation

BACKGROUND

Selection of appropriate treatment for patients with recurrent brain metastasis (BM) remains uncertain. Recent studies have demonstrated a significant response rate and acceptable toxicity using fractionated stereotactic radiosurgery (FSRS) in patients with locally recurrent large BM. The aim of this study was to evaluate efficacy and toxicity of FSRS with bevacizumab as a new salvage treatment for locally recurrent BM with previous high-dose irradiation.

METHODS

Patients with recurrent BM previously irradiated were enrolled. Salvage FSRS dose was 9.5-29 Gy (2-5 fractions) with 62%-75% isodose line by CyberKnife according to the brain tumor volume, site, and previous dose. Bevacizumab was prescribed for 4 cycles (5 mg/kg, every 3 weeks). The primary objective was to identify the overall survival after salvage treatment. Secondary objectives included clinical response (Karnofsky performance scale), imaging response (magnetic resonance imaging) and treatment-related adverse events.

RESULTS

From December 2009 to October 2016, 24 patients were enrolled. The 1-year overall survival after salvage stereotactic radiosurgery was 87.5%. Twenty-three (96%) patients had a positive imaging response with a T2 volume reduction range of 6-22 cm³ (median 14 cm³, P = 0.032, paired t test). Significant clinical improvement was achieved (best Karnofsky performance scale score, P < 0.05, paired t test). Grade 1/2 fatigue was observed in 8 (33%) patients. Grade 3 fatigue and headache occurred in 1 patient.

CONCLUSIONS

FSRS with adjuvant bevacizumab treatment showed favorable clinical and radiologic control as a salvage treatment regimen. The diagnoses of radiation necrosis and local recurrence after salvage FSRS warrant further study.

Reirradiation of Recurrent Brain Metastases: Where Do We Stand?

Brain metastases occur in a large portion of patients with cancer. Although advances in radiotherapy have helped to improve survival, they have also raised questions regarding the best modality for retreatment in the context of recurrent disease. The spectrum of treatment options for recurrent intracranial metastatic disease after previous radiotherapy includes salvage stereotactic radiosurgery, whole brain radiotherapy, and brachytherapy. We have comprehensively reviewed the existing data on the efficacy and toxicity of the various reirradiation treatment modalities. We examined the key clinical considerations that guide patient selection, such as dose, tumor size, interval to retreatment, and local control and survival rates.

Brain metastases: radiosurgery

Stereotactic radiosurgery has revolutionized the management of brain metastases. It delivers focused, highly conformal, ionizing radiation to a tumor delineated using high-resolution imaging, with low toxicity to adjacent brain structures. Randomized controlled and prospective trials have demonstrated a survival advantage and high local control rates after stereotactic radiosurgery for metastatic disease to the central nervous system, including for up to 10 brain metastases. Its minimal-access nature makes it an attractive alternative to surgical resection. Furthermore, in addition to chemotherapy, newer targeted therapies and immunotherapies with improved side-effect profiles allow for the concurrent delivery of systemic therapy with radiosurgery, with possible additive or synergistic effects, expediting the treatment of both extracranial and intracranial disease. The modern management of brain metastasis patients should include consideration of routine staging and surveillance magnetic resonance imaging scans in patients with higher-stage cancer to detect intracranial metastases earlier and treat promptly with radiosurgery in order to prevent the development of neurologic symptoms and the need for surgical resection.

Prospective study of 11C-methionine PET for distinguishing between recurrent brain metastases and radiation necrosis: limitations of diagnostic accuracy and long-term results of salvage treatment

Background

On conventional diagnostic imaging, the features of radiation necrosis (RN) are similar to those of local recurrence (LR) of brain metastases (BM). ¹¹C–methionine positron emission tomography (MET-PET) is reportedly useful for making a differential diagnosis between LR and RN. In this prospective study, we aimed to investigate the diagnostic performance of MET-PET and the long-term results of subsequent patient management.

Methods

The eligible subjects had enlarging contrast-enhanced lesions (>1 cm) on MR imaging after any form of radiotherapy for BM, suggesting LR or RN. However, it was difficult to differentiate LR from RN in these cases. From August 2013 to February 2017, MET-PET was performed for 37 lesions in 32 eligible patients. Tracer accumulation in the regions of interest was analysed as the standardised uptake value (SUV) and maximal lesion SUV/maximal normal tissue SUV ratios (LNR) were calculated. The cut-off value for LNR was provisionally set at 1.40. Salvage treatment strategies determined based on MET-PET diagnosis and treatment results were investigated. The diagnostic accuracy of MET-PET was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

The median interval from primary radiotherapy to MET-PET was 19 months and radiotherapy had been performed twice or more for 13 lesions. The MET-PET diagnoses were LR in 19 and RN in 18 lesions. The mean values and standard deviation of LNRs for each diagnostic category were 1.70 ± 0.30 and 1.09 ± 0.25, respectively. At the median follow-up time of 18 months, final diagnoses were confirmed histologically for 17 lesions and clinically for 20 lesions. ROC curve analysis indicated the optimal LNR cut-off value to be 1.40 (area under the curve: 0.84), and the sensitivity and specificity were 0.82 and 0.75, respectively. The median survival times of patient groups with LR and RN based on MET-PET diagnosis were 14.8 months and 35.1 months, respectively (P = 0.035, log-rank test).

Conclusions

MET-PET showed apparently reliable diagnostic performance for distinguishing between LR and RN. The provisional LNR cut-off value of 1.4 in our institution was found to be appropriate. Limitations of diagnostic accuracy should be recognised in cases with LNR close to this cut-off value.

Toxicity of concurrent stereotactic radiotherapy and targeted therapy or immunotherapy: A systematic review

BACKGROUND AND PURPOSE

Both stereotactic radiotherapy (SRT) and immune- or targeted therapy play an increasingly important role in personalized treatment of metastatic disease. Concurrent application of both therapies is rapidly expanding in daily clinical practice. In this systematic review we summarize severe toxicity observed after concurrent treatment.

MATERIAL AND METHODS

PubMed and EMBASE databases were searched for English literature published up to April 2016 using keywords "radiosurgery", "local ablative therapy", "gamma knife" and "stereotactic", combined with "bevacizumab", "cetuximab", "crizotinib", "erlotinib", "gefitinib", "ipilimumab", "lapatinib", "sorafenib", "sunitinib", "trastuzumab", "vemurafenib", "PLX4032", "panitumumab", "nivolumab", "pembrolizumab", "alectinib", "ceritinib", "dabrafenib", "trametinib", "BRAF", "TKI", "MEK", "PD1", "EGFR", "CTLA-4" or "ALK". Studies performing SRT during or within 30days of targeted/immunotherapy, reporting severe (⩾Grade 3) toxicity were included.

RESULTS

Concurrent treatment is mostly well tolerated in cranial SRT, but high rates of severe toxicity were observed for the combination with BRAF-inhibitors. The relatively scarce literature on extra-cranial SRT shows a potential risk of increased toxicity when SRT is combined with EGFR-targeting tyrosine kinase inhibitors and bevacizumab, which was not observed for cranial SRT.

CONCLUSIONS

This review gives a best-possible overview of current knowledge and its limitations and underlines the need for a timely generation of stronger evidence in this rapidly expanding field.

Stereotactic laser ablation as treatment for brain metastases that recur after stereotactic radiosurgery: a multiinstitutional experience

OBJECTIVE

Therapeutic options for brain metastases (BMs) that recur after stereotactic radiosurgery (SRS) remain limited.

METHODS

The authors provide the collective experience of 4 institutions where treatment of BMs that recurred after SRS was performed with stereotactic laser ablation (SLA).

RESULTS

Twenty-six BMs (in 23 patients) that recurred after SRS were treated with SLA (2 patients each underwent 2 SLAs for separate lesions, and a third underwent 2 serial SLAs for discrete BMs). Histological findings in the BMs treated included the following: breast (n = 6); lung (n = 6); melanoma (n = 5); colon (n = 2); ovarian (n = 1); bladder (n = 1); esophageal (n = 1); and sarcoma (n = 1). With a median follow-up duration of 141 days (range 64–794 days), 9 of the SLA-treated BMs progressed despite treatment (35%). All cases of progression occurred in BMs in which < 80% ablation was achieved, whereas no disease progression was observed in BMs in which ≥ 80% ablation was achieved. Five BMs were treated with SLA, followed 1 month later by adjuvant SRS (5 Gy daily × 5 days). No disease progression was observed in these patients despite ablation efficiency of < 80%, suggesting that adjuvant hypofractionated SRS enhances the efficacy of SLA. Of the 23 SLA-treated patients, 3 suffered transient hemiparesis (13%), 1 developed hydrocephalus requiring temporary ventricular drainage (4%), and 1 patient who underwent SLA of a 28.9-cm3 lesion suffered a neurological deficit requiring an emergency hemicraniectomy (4%). Although there is significant heterogeneity in corticosteroid treatment post-SLA, most patients underwent a 2-week taper.

CONCLUSIONS

Stereotactic laser ablation is an effective treatment option for BMs in which SRS fails. Ablation of ≥ 80% of BMs is associated with decreased risk of disease progression. The efficacy of SLA in this setting may be augmented by adjuvant hypofractionated SRS.