Phase 3 trials of stereotactic radiosurgery with or without whole-brain radiation therapy for 1 to 4 brain metastases: individual patient data meta-analysis

Innovations in radiotherapy and advances in immunotherapy for the treatment of brain metastases

Radiotherapy for brain metastases has evolved tremendously over the past four decades, allowing for improved intracranial control of disease with reduced neurotoxicity. The main technological advance was provided by volumetric modulated arc therapy (VMAT), a computer-controlled delivery method that has opened the door for single-isocenter multi-metastases stereotactic radiosurgery (SRS) and hippocampal avoidance whole brain radiation therapy (HA-WBRT). Other notable advances have occurred in the combination of immune checkpoint inhibitors (ICI) and radiosurgery. When these two modalities are combined in the proper sequence (within 30 days from each other), it provides promising results in the treatment of intracranial metastases from melanoma. There is emerging evidence of a synergistic interaction between ICI and SRS, providing better intracranial tumor control and lengthening the survival of patients afflicted by this common complication of cancer.

Clinical assessment of a biophysical model for distinguishing tumor progression from radiation necrosis

PURPOSE

The efficacy of an imaging-driven mechanistic biophysical model of tumor growth for distinguishing radiation necrosis from tumor progression in patients with enhancing lesions following stereotactic radiosurgery (SRS) for brain metastasis is validated.

METHODS

We retrospectively assessed the model using 73 patients with 78 lesions and histologically confirmed radiation necrosis or tumor progression. Postcontrast T1-weighted MRI images were used to extract parameters for a mechanistic reaction-diffusion logistic growth model mechanically coupled to the surrounding tissue. The resulting model was then used to estimate mechanical stress fields, which were then compared with edema visualized on FLAIR imaging using DICE similarity coefficients. DICE, model, and standard radiographic morphometric analysis parameters were evaluated using a receiver operating characteristic (ROC) curve for prediction of radiation necrosis or tumor progression. Multivariate logistic regression models were then constructed using mechanistic model parameters or advanced radiomic features. An independent validation was performed to evaluate predictive performance.

RESULTS

Tumor cell proliferation rate resulted in ROC AUC = 0.86, 95% CI: 0.76-0.95, P < 0.0001, 74% sensitivity and 95% specificity) and DICE similarity coefficient associated with high stresses demonstrated an ROC AUC = 0.93, 95% CI: 0.86-0.99, P < 0.0001, 81% sensitivity and 95% specificity. In a multivariate logistic regression model using an independent validation dataset, mechanistic modeling parameters had an ROC AUC of 0.95, with 94% sensitivity and 96% specificity.

CONCLUSIONS

Imaging-driven biophysical modeling of tumor growth represents a novel method for accurately predicting clinically significant tumor behavior.

WBRT for brain metastases from non-small cell lung cancer: for whom and when?-Contemporary point of view

The incidence of brain metastases (BM) is estimated between 20% and 40% of patients with solid cancer. The most common cause of this failure is lung cancer, and in locally advanced non-small cell lung cancer (NSCLC) BM represent a common site of relapse in 30-55% cases. The basic criteria of therapeutic decision-making are based on the significant prognostic factors which are components of prognostic scores. The standard approach to treatment of BM from NSCLC include whole brain radiotherapy (WBRT) which is used as adjuvant modality after local therapy (surgery or stereotactic radiosurgery) or as primary treatment and it remains the primary modality of treatment for patients with multiple metastases. WBRT is also used in combination with systemic therapy. The aim of presented review of literature is trying to answer which patients with BM from NSCLC should receive WBRT and when it could be omitted. There were presented the aspects of application of WBRT in relation to (I) choice between WBRT or the best supportive care and (II) employment of WBRT in combination with local treatment modalities [surgical resection or stereotactic radio-surgery (SRS)] and/or with systemic therapy. According to data from literature we concluded that the most important factor that needs to be considered when assessing the suitability of a patient for WBRT is the patient's prognosis based on the Lung-molGPA score. WBRT should be applied in treatment of multiple BM from lung cancer in patients with favourable prognosis and in in patients with presence of EML4-ALK translocation before therapy with crizotinib. Whereas WBRT could be omitted in patients with poor prognosis and after primary SRS.

Executive summary from American Radium Society's appropriate use criteria on neurocognition after stereotactic radiosurgery for multiple brain metastases

BACKGROUND

The American Radium Society (ARS) Appropriate Use Criteria brain malignancies panel systematically reviewed (PRISMA [Preferred Reporting Items for Systematic Reviews and Meta-Analyses]) published literature on neurocognitive outcomes after stereotactic radiosurgery (SRS) for patients with multiple brain metastases (BM) to generate consensus guidelines.

METHODS

The panel developed 4 key questions (KQs) to guide systematic review. From 11 614 original articles, 12 were selected. The panel developed model cases addressing KQs and potentially controversial scenarios not addressed in the systematic review (which might inform future ARS projects). Based upon quality of evidence, the panel confidentially voted on treatment options using a 9-point scale of appropriateness.

RESULTS

The panel agreed that SRS alone is usually appropriate for those with good performance status and 2-10 asymptomatic BM, and usually not appropriate for >20 BM. For 11-15 and 16-20 BM there was (between 2 case variants) agreement that SRS alone may be appropriate or disagreement on the appropriateness of SRS alone. There was no scenario (among 6 case variants) in which conventional whole-brain radiotherapy (WBRT) was considered usually appropriate by most panelists. There were several areas of disagreement, including: hippocampal sparing WBRT for 2-4 asymptomatic BM; WBRT for resected BM amenable to SRS; fractionated versus single-fraction SRS for resected BM, larger targets, and/or brainstem metastases; optimal treatment (WBRT, hippocampal sparing WBRT, SRS alone to all or select lesions) for patients with progressive extracranial disease, poor performance status, and no systemic options.

CONCLUSIONS

For patients with 2-10 BM, SRS alone is an appropriate treatment option for well-selected patients with good performance status. Future study is needed for those scenarios in which there was disagreement among panelists.

Fractionated Stereotactic Radiation Therapy Using Volumetric Modulated Arc Therapy in Patients with Solitary Brain Metastases

Purpose

To analyze retrospectively the clinical efficacy and safety for patients treated with fractionated stereotactic radiation therapy (FSRT) using volumetric modulated arc therapy.

Methods

Between 2016 and 2017, 46 patients with solitary brain metastasis who underwent FSRT consisting of 25-40 Gy/5 fractions were recruited in this study. All targets within the same course received different prescriptions according to size. Toxicities were graded according to the Common Terminology Criteria for Adverse Events version 4.0.

Results

The median follow-up was 11 months (3-53 months). The 6-month and 12-month local control rate calculated by Kaplan-Meier estimate was, respectively, 95% and 86%. Tumor diameter < 2.5 cm obtained 100% improved 12-month local control rate compared with 66% in those with ≥2.5 cm (P < 0.001). The 12-month local control calculated by Kaplan-Meier estimate was 95% in tumors with >30 Gy treatment and only 60% in tumors with ≤30 Gy treatment (P = 0.001). Multivariate analysis revealed that the prescription dose ≤ 30 Gy resulted in increased local failure (hazard ratio (HR), 0.14 (range, 0.019-0.95; P = .046)). Grade 3 or worse toxic effects were found in 5 (11%) patients, and no patient experienced surgical resection for symptomatic radioactive necrosis.

Conclusions

FSRT for solid brain metastasis appears to have the advantages of a high rate of local control with a minimal risk of severe toxicity and deserves application in the clinical practice.

Current treatment options for HER2-positive breast cancer patients with brain metastases

Brain metastases (BMs) are frequently associated with HER2+ breast cancer (BC). Their management is based on a multi-modal strategy including both local treatment and systemic therapy. Despite therapeutic advance, BMs still have an adverse impact on survival and quality of life and the development of effective systemic therapy to prevent and treat BMs from HER2 + BC represents an unmet clinical need. Trastuzumab-based therapy has long been the mainstay of systemic therapy and over the last two decades other HER2-targeted agents including lapatinib, pertuzumab and trastuzumab emtansine, have been introduced in the clinical practice. More recently, novel agents such as neratinib, tucatinib and trastuzumab deruxtecan have been developed, with interesting activity against BMs. Further research is needed to better elucidate the best sequence of these agents and their combination with local treatment.

Micropapillary Predominance Is a Risk Factor for Brain Metastasis in Resected Lung Adenocarcinoma

BACKGROUND

Histologic subtyping offers some prognostic value in lung adenocarcinoma. We thus hypothesized that histologic subtypes may be useful for risk stratification of brain metastasis (BM). In this study, we aimed to investigate the impact of histologic subtypes on the risk for BM in patients with resected lung adenocarcinoma.

PATIENTS AND METHODS

Of 1099 consecutive patients who had undergone curative-intent surgery (2000-2014), 448 patients who had undergone complete resection for lung adenocarcinoma were included in this study. Correlated clinical variables and BM-free survival were analyzed.

RESULTS

Micropapillary predominance was significantly associated with higher risk of BM after complete resection in univariate analyses (P < .001). In addition, multivariate analyses showed that micropapillary predominance was an independent risk factor for BM (hazard ratio = 2.727; 95% confidence interval, 1.260-5.900; P = .011), along with younger age and advanced pathologic stage. Unlike the other subtypes, an increase in the percentage of the micropapillary subtype was positively correlated with an increase in BM frequency. Patients with micropapillary adenocarcinoma showed significantly poorer brain metastasis-free survival compared with those with non-micropapillary adenocarcinoma (3 years, 78.2% vs. 95.6%; 5 years, 67.3% vs. 94.3%; P < .001).

CONCLUSION

The current study demonstrated a significant correlation between micropapillary subtype and higher risk of BM in patients with resected lung adenocarcinoma. This routine histologic evaluation of resected adenocarcinoma may provide useful information for the clinician when considering postoperative management in patients with lung adenocarcinoma. Histologic subtyping offer some prognostic value in lung adenocarcinoma. Because brain metastasis is critical and often refractory to systemic chemotherapy, early detection is clinically important to achieve effective local treatment. We retrospectively analyzed the association between histologic subtypes and occurrence of brain metastasis and found a significant association between micropapillary predominance and higher risk for brain metastasis. Our findings may be relevant when considering postoperative management.

Phase III randomized study of carboplatin pemetrexed with or without bevacizumab with initial versus "at progression" cerebral radiotherapy in advanced non squamous non-small cell lung cancer with asymptomatic brain metastasis

Background:

The role and timing of whole or stereotaxic brain radiotherapy (BR) in patients with advanced non-small cell lung cancer (aNSCLC) and asymptomatic brain metastases (aBMs) are not well established. This study investigates whether deferring BR until cerebral progression was superior to upfront BR for patients with aNSCLC and aBM.

Methods:

This open-label, multicenter, phase III trial, randomized (1:1) aNSCLC patients with aBMs to receive upfront BR and chemotherapy: platin–pemetrexed and bevacizumab in eligible patients, followed by maintenance pemetrexed with or without bevacizumab, BR arm, or the same chemotherapy with BR only at cerebral progression, chemotherapy (ChT) arm. Primary endpoint was progression-free survival (PFS), secondary endpoints were overall survival (OS), global, extra-cerebral and cerebral objective response rate (ORR), toxicity, and quality of life [ClinicalTrials.gov identifier: NCT02162537].

Results:

The trial was stopped early because of slow recruitment. Among 95 included patients, 91 were randomized in 24 centers: 45 to BR and 46 to ChT arms (age: 60 ± 8.1, men: 79%, PS 0/1: 51.7%/48.3%; adenocarcinomas: 92.2%, extra-cerebral metastases: 57.8%, without differences between arms.) Significantly more patients in the BR-arm received BR compare with those in the ChT arm (87% versus 20%; p < 0.001); there were no significant differences between BR and ChT arms for median PFS: 4.7, 95% confidence interval (CI):3.4–7.5 versus 4.8, 95% CI: 2.4–6.5 months, for median OS: 8.5, 95% CI:.6–11.1 versus 8.3, 95% CI:4.5–11.5 months, cerebral and extra-cerebral ORR (27% versus 13%, p = 0.064, and 30% versus 41%, p = 0.245, respectively). The ChT arm had more grade 3/4 neutropenia than the BR arm (13% versus 6%, p = 0.045); others toxicities were comparable.

Conclusion:

The significant BR rate difference between the two arms suggests that upfront BR is not mandatory in aNSCLC with aBM but this trial failed to show that deferring BR for aBM is superior in terms of PFS from upfront BR.

The effect of low-dose radiation spillage during stereotactic radiosurgery for brain metastases on the development of de novo metastases

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165 new brain lesions in 38 patients who had prior SRS for brain metastases.

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73% primary lung cancer patients.

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Lower incidence of new lesions with increasing dose received by the region from prior SRS.

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Accounting for discrepancies in both volume of the brain and follow-up period, regions that received doses of 4 Gy or more from previous SRS had 3 or fewer new lesions compared to 17 new lesions per 100 cm3 brain per year in regions that received 1 Gy or less.

Purpose/Objective(s)

Stereotactic radiosurgery (SRS) for metastatic disease to the brain is associated with higher in-brain failures compared to whole brain radiation therapy (WBRT). Here we investigated the relationship between low-dose fall off during SRS and location of new brain lesions.

Materials and Methods

One hundred sixty-seven patients treated with single fraction or fractionated SRS for intact or resected brain metastases at our institution from January 2016 to June 2018 were reviewed. Patients with imaging findings of new brain metastases after the initial SRS were included. Patients with WBRT before SRS were excluded. MRI scans for repeat treatments were fused with initial SRS plan. New lesions were outlined on the initial SRS planning CT. The mean dose that the site of new lesions received from initial SRS was tabulated.

Results

Thirty-eight patients met inclusion criteria. 165 new lesions were evaluated. There was a lower propensity to develop new brain lesions with increasing dose received by the regions from prior SRS, with 66%, 34%, 19%, 13%, 6%, 5%, 2% and 1% of new lesions appearing in regions that received less than 1 Gy, greater than or equal to 1, 2, 3, 4, 5, 6, and 7 Gy, respectively. Higher doses are received by smaller brain volumes during SRS. After accounting for volume, 14, 14, 11, 7, 2, 2, 1 and 1 new lesions appeared per 100 cm³ of brain in regions that received doses of less than 1 Gy, greater than or equal to 1, 2, 3, 4, 5, 6, and 7 Gy, respectively, from prior SRS.

Conclusions

We identified low dose spillage during SRS to be associated with lower incidence of new brain metastases. Validation in larger dataset or prospective study of the combination of SRS with low dose WBRT would be crucial in order to establish causality of these findings.

Prognostic factors and survival after whole-brain radiotherapy for initial brain metastases arising from non-small cell lung cancer

Aim:

To identify prognostic factors and investigate patient survival after whole-brain radiotherapy (WBRT) for initial brain metastases arising from non-small cell lung cancer (NSCLC).

Methods:

Patients diagnosed with NSCLC between 1 January 2010 and 30 September 2019, and who received WBRT upon first developing a brain metastasis, were investigated. Overall survival was determined as related to age, sex, duration between initial examination and brain metastasis detection, stage at the first examination, presence of metastases outside the brain, blood analysis findings, brain metastasis symptoms, radiotherapy dose and completion, imaging findings, therapeutic course of chemotherapy and/or radiation therapy, histological type, and gene mutation status.

Results:

Thirty-one consecutive patients (20 men and 11 women) with a mean age of 63·8 years and median survival of 129 days were included. Multivariate analysis with stepwise testing was performed to investigate differences in survival according to gene mutation status, lactate dehydrogenase (LDH) level, irradiation dose, WBRT completion and Stage status. Of these, a statistically significant difference in survival was observed in patients with gene mutation status (hazard ratio: 0·31, 95% CI: 0·11–0·86, p = 0·025), LDH levels <230 vs. ≥230 IU/L (hazard ratio: 4·08, 95% CI: 1·45–11·5, p < 0·01) received 30 Gy, 30 Gy/10 fractions to 35 Gy/14 fractions, and 37·5 Gy/15 fractions (hazard ratio: 0·26, 95% CI: 0·09–0·71, p < 0·01), and stage IV versus non-stage IV (hazard ratio: 0·13, 95 CI:0·02–0·64, p < 0·01)

Findings:

Gene mutation, LDH, radiation dose and Stage are prognostic factors for patients with initial brain metastases who are treated with WBRT.

The Management of Brain Metastases-Systematic Review of Neurosurgical Aspects

Simple Summary

In this comprehensive review, we focused on the neurosurgical treatment as an integrative part of the challenging multidisciplinary management of cerebral metastases, a neuro-oncologic entity, which has been observed to have an increased incidence over the last years. In selected cases, the surgical removal of the space-occupying mass reduces the intracranial pressure, normalizes the metabolic environment, reduces the symptom burden, and allows for the intensification of local and systemic adjuvant treatment. In detail, we discuss the incidence of brain metastases, the role of surgical resection, as well as the evolution of current neurosurgical techniques, the surgical morbidity and mortality of single and multiple lesions, and we enlighten the role of surgery for recurrent tumors.

Abstract

The multidisciplinary management of patients with brain metastases (BM) consists of surgical resection, different radiation treatment modalities, cytotoxic chemotherapy, and targeted molecular treatment. This review presents the current state of neurosurgical technology applied to achieve maximal resection with minimal morbidity as a treatment paradigm in patients with BM. In addition, we discuss the contribution of neurosurgical resection on functional outcome, advanced systemic treatment strategies, and enhanced understanding of the tumor biology.

Co-Occurrence Conundrum: Brain Metastases from Lung Adenocarcinoma, Radiation Necrosis, and Gliosarcoma

Non-small cell lung cancer (NSCLC) commonly presents with metastasis to the brain. When brain metastases are treated with stereotactic radiosurgery (SRS), longitudinal imaging to monitor treatment response may identify radiation necrosis, metastasis progression, and/or another primary brain malignancy. A 60-year-old female with metastatic NSCLC involving the brain underwent treatment with systemic therapy and SRS. While some brain metastases resolved, two remaining sites evolved to resemble radiation necrosis on magnetic resonance imaging and spectroscopy. One of those sites was later confirmed to be radiation necrosis after receding with steroids and bevacizumab. The other lesion continued to enlarge and was then surgically resected, pathologically proven to be a gliosarcoma. When scan findings diverge among multiple treated disease sites, imaging should be cautiously interpreted in conjunction with clinical information as well as early surgical consultation for biopsy consideration, especially when there is suspicion of unusual or superimposed pathologies.

Prophylactic cranial irradiation reduces the incidence of brain metastasis in a mouse model of metastatic, HER2-positive breast cancer

Prophylactic cranial irradiation (PCI) can reduce the incidence of brain metastasis and improve overall survival in some patients with acute lymphoblastic leukemia or small-cell lung cancer. We examined the potential effects of PCI in a mouse model of breast cancer brain metastasis. The HER2+ inflammatory breast cancer cell line MDA-IBC3 was labeled with green fluorescent protein and injected via tail-vein into female SCID/Beige mice. Mice were then given 0 Gy or 4 Gy of whole-brain irradiation 2 days before tumor-cell injection or 5 days, 3 weeks, or 6 weeks after tumor-cell injection. Mice were sacrificed 4-weeks or 8-weeks after injection and brain tissues were examined for metastasis by fluorescent stereomicroscopy. In the unirradiated control group, brain metastases were present in 77% of mice at 4 weeks and in 90% of mice at 8 weeks; by comparison, rates for the group given PCI at 5 days after tumor-cell injection were 20% at 4 weeks (p=0.01) and 30% at 8 weeks (p=0.02). The PCI group also had fewer brain metastases per mouse at 4 weeks (p=0.03) and 8 weeks (p=0.006) versus the unirradiated control as well as a lower metastatic burden (p=0.01). Irradiation given either before tumor-cell injection or 3-6 weeks afterward had no significant effect on brain metastases compared to the unirradiated control. These results underscore the importance of timing for irradiating subclinical disease. Clinical whole brain strategies to target subclinical brain disease as safely as possible may warrant further study.

Impact of EGFR mutation on outcomes following SRS for brain metastases in non-small cell lung cancer

INTRODUCTION

Patients with EGFR-mutated (EGFRm) non-small cell lung cancer (NSCLC) are at particularly high risk of developing brain metastases (BrM). In addition to EGFR targeting tyrosine kinase inhibitors (TKI), radiosurgery (SRS) has an important role in the management of EGFRm BrM. However, data specific to the response and toxicity of EGFRm BrM to SRS are sparse. We evaluated the incidence of local failure (LF) and toxicity of EGFRm and EGFR-wild-type (EGFRwt) BrM treated with SRS.

METHODS

We analyzed a prospective registry of BrM patients treated at our centre between 2008 and 2017 and identified EGFRm and EGFRwt NSCLC patients treated with SRS ± systemic therapy for BrM. Incidences of local failure (LF) and radionecrosis (RN) were determined, and Cox regression was performed for univariate and multivariate analyses (MVAs).

RESULTS

We analyzed data from 218 patients (615 lesions - 225 EGFRm and 390 EGFRwt). Median imaging follow-up per patient was 14.5 months (0.5-96.3). Prior to or concomitant with SRS, 62 % of EGFRm patients received TKI and 93 % received TKI post SRS. The 24-month incidence of LF was 6% and 16 % for EGFRm BrM and EGFRwt, respectively (0.43(0.19-0.95); p = 0.037). The 24-month incidence of RN was 4% and 6% for EGFRm and EGFRwt BrM, respectively (0.8(0.32-1.98) p = 0.63). On MVA, BrM size and prescription dose (PD) significantly correlated with a higher risk of LF and BrM size correlated with a higher risk of RN.

CONCLUSION

We observed excellent rates of response and toxicity following SRS in EGFRm compared to EGFRwt NSCLC, suggesting that EGFRm BrM have a favourable risk benefit ratio compared to EGFRwt NSCLC.

Effects of systemic therapy and local therapy on outcomes of 873 breast cancer patients with metastatic breast cancer to brain: MD Anderson Cancer Center experience

Outcomes of treatments for patients with breast cancer brain metastasis (BCBM) remain suboptimal, especially for systemic therapy. To evaluate the effectiveness of systemic and local therapy (surgery [S], stereotactic radiosurgery [SRS] and whole brain radiotherapy [WBRT]) in BCBM patients, we analyzed the data of 873 BCBM patients from 1999 to 2012. The median overall survival (OS) and time to progression in the brain (TTP-b) after diagnosis of brain metastases (BM) were 9.1 and 7.1 months, respectively. WBRT prolonged OS in patients with multiple BM (hazard ratio [HR], 0.68; 95% CI, 0.52-0.88; P = .004). SRS alone, and surgery or SRS followed by WBRT (S/SRS + WBRT), were equivalent in OS and TTP-b (median OS, 14.9 vs 17.2 months; median TTP-b, 8.2 vs 8.6 months). Continued chemotherapy prolonged OS (HR, 0.35; 95% CI, 0.30-0.41; P < .001) and TTP-b (HR, 0.48; 95% CI, 0.33-0.70; P < .001), however, with no advantage of capecitabine over other chemotherapy agents used (median OS, 11.8 vs 12.4 months; median TTP-b, 7.2 vs 7.4 months). Patients receiving trastuzumab at diagnosis of BM, continuation of anti-HER2 therapy increased OS (HR, 0.53; 95% CI, 0.34-0.83; P = .005) and TTP-b (HR, 0.41; 95% CI, 0.23-0.74; P = .003); no additional benefit was seen with switching over between trastuzumab and lapatinib (median OS, 18.4 vs 22.7 months; median TTP-b: 7.4 vs 8.7 months). In conclusion, SRS or S/SRS + WBRT were equivalent for patients' OS and local control. Continuation systemic chemotherapy including anti-HER2 therapy improved OS and TTP-b with no demonstrable advantage of capecitabine and lapatinib over other agents of physicians' choice was observed.

Poor performance status and brain metastases treatment: who may benefit from the stereotactic radiotherapy?

BACKGROUND

Poor Performance Status (PS) of cancer patients, defined as PS score 2-3, is an impediment for many drug- and irradiation-based treatments, supported by the trials that exclude subjects with PS < 1. Reports on the benefits of stereotactic radiotherapy (SRT) for brain metastases (BMs) in poor PS patients are scarce. We sought to review the characteristics and survival outcomes of this cohort, to assess who may benefit most from SRT.

METHODS

We retrospectively evaluated 73 patients with PS 2 or 3 (63 and 10 cases) treated with SRT for 150 BMs from 2012 to 2018. Patients' characteristics and post-SRT survival, stratified by concomitant systemic treatment (CST) were assessed using the Kaplan-Meier method (p-value < 0.05).

RESULTS

Non-small cell lung cancer was the most frequent primary tumor. Extracranial metastases were present in 86.3% of patients. The median overall survival (mOS) after SRT was estimated as 6.0 months (range 0.2-37.7), with 6- and 12-month survival rates of 51.0% and 21.0%, respectively. CST was administrated to 59.7% of patients (immunotherapy, target therapy or chemotherapy). Patients treated with CST presented larger mOS (6.7 vs. 4.4 months for patients treated with SRT alone, p = 0.3), and better 6- and 12-month survival rates (59% and 24% vs. 37% and 18% in patients not treated with CST).

CONCLUSIONS

Survival rate after SRT for BMs in poor performance patients, especially with PS 2, can justify SRT, in particular if an effective systemic treatment is available. Both SRT and CST should be more accessible for these patients in clinical practice.

The individual risk of symptomatic radionecrosis after brain metastasis radiosurgery is predicted by a continuous function of the V12Gy

Introduction

Brain metastases are frequently treated with stereotactic radiosurgery (SRS). Radionecrosis (RN) is the late side effect in up to 24% of patients, being symptomatic in 8-10%. Fixed values of the radiosurgical volume receiving 12 Gy or more (V12Gy) are used to roughly predict the global risk. The aim of this retrospective study is to fine-tune the model of individual risk prediction for symptomatic radionecrosis and identify modulating factors.

Materials and methods

Data of patients treated with SRS for ≤3 BM of solid tumours at CHU-UCL-Namur were retrospectively reviewed. Doses ranging from 15 to 24 Gy were prescribed to the 70% isodose in function of the lesion diameter. Treatment was administered with a stereotactic linear accelerator. Follow-up magnetic resonance imaging was performed 3-monthly for 18 months and 6-monthly thereafter. RN was prospectively diagnosed and confirmed by the tumour board. V12Gy, previous or salvage whole-brain radiotherapy (WBRT), smoking history, diabetes, postoperative SRS, diagnosis-specific graded prognostic assessment score, cerebral lobe location and relative location (superficial versus deep) were retrieved. Univariate and multivariate analyses were performed to assess their predictive values and derive a model.

Results

128 patients with 220 lesions were analysed. The risk of RN was predicted by a continuous function of the V12Gy (p = 0.005). No other factor had a significant impact, particularly WBRT that did not increase the risk.

Conclusion

The risk of symptomatic RN is predicted on an individual basis by a model in function of the V12Gy and must be confirmed in a prospective study.

Brain Metastases from Uterine Cervical and Endometrial Cancer

Simple Summary

This review investigated the prevalence, clinical characteristics, clinical presentation, diagnosis, treatment, and prognosis of patients with brain metastases from uterine cervical carcinoma (CC) and uterine endometrial carcinoma (EC). The findings of this review indicate the factors that can facilitate better treatment selection and, consequently, better outcomes in patients with CC and EC.

Abstract

Reports on brain metastases (BMs) from uterine cervical carcinoma (CC) and uterine endometrial carcinoma (EC) have recently increased due to the development of massive databases and improvements in diagnostic procedures. This review separately investigates the prevalence, clinical characteristics, clinical presentation, diagnosis, treatment, and prognosis of BMs from CC and uterine endometrial carcinoma EC. For patients with CC, early-stage disease and poorly differentiated carcinoma lead to BMs, and elderly age, poor performance status, and multiple BMs are listed as poor prognostic factors. Advanced-stage disease and high-grade carcinoma are high-risk factors for BMs from EC, and multiple metastases and extracranial metastases, or unimodal therapies, are possibly factors indicating poor prognosis. There is no “most effective” therapy that has gained consensus for the treatment of BMs. Treatment decisions are based on clinical status, number of the metastases, tumor size, and metastases at distant organs. Surgical resection followed by adjuvant radiotherapy appears to be the best treatment approach to date. Stereotactic ablative radiation therapy has been increasingly associated with good outcomes in preserving cognitive functions. Despite treatment, patients died within 1 year after the BM diagnosis. BMs from uterine cancer remain quite rare, and the current evidence is limited; thus, further studies are needed.

Clinicopathologic and Treatment Features of Long-Term Surviving Brain Metastasis Patients

Background: The purpose of our study was to characterize clinical features among brain metastasis (BM) patients who were long term survivors (LTS). Methods: We reviewed a registry of BM patients referred to our multidisciplinary BM clinic between 2006 and 2014 and identified 97 who lived ≥ 3 years following BM diagnosis. The clinical and treatment characteristics were obtained from a prospectively maintained database, and additional information was obtained through review of electronic medical records and radiologic images. Survival analyses were performed using the Kaplan-Meier method. Results: Median follow up for LTS was 67 months (range 36–181). Median age was 54 years, 65% had single BM, 39% had stable extracranial disease at the time of BM treatment, and brain was the first site of metastasis in 76%. Targetable mutations were present in 39% of patients and 66% received treatment with targeted-, hormonal-, or immuno-therapy. Brain surgery at the time of diagnosis was performed in 40% and stereotactic radiosurgery (SRS) or whole brain radiotherapy (alone or combination) in 52% and 56%, respectively. Following initial BM treatment, 5-year intracranial disease-free survival was 39%, and the cumulative incidence of symptomatic radio-necrosis was 16%. Five and ten-year overall survival was 72% and 26%, respectively. Conclusion: Most LTS were younger than 60 years old and had a single BM. Many received treatment with surgery or targeted, immune, or hormonal therapy.

Automatic detection and segmentation of multiple brain metastases on magnetic resonance image using asymmetric UNet architecture

Detection of brain metastases is a paramount task in cancer management due both to the number of high-risk patients and the difficulty of achieving consistent detection. In this study, we aim to improve the accuracy of automated brain metastasis (BM) detection methods using a novel asymmetric UNet (asym-UNet) architecture. An end-to-end asymmetric 3D-UNet architecture, with two down-sampling arms and one up-sampling arm, was constructed to capture the imaging features. The two down-sampling arms were trained using two different kernels (3 × 3 × 3 and 1 × 1 × 3, respectively) with the kernel (1 × 1 × 3) dominating the learning. As a comparison, vanilla single 3D UNets were trained with different kernels and evaluated using the same datasets. Voxel-based Dice similarity coefficient (DSC_v), sensitivity (S _v), precision (P _v), BM-based sensitivity (S _BM), and false detection rate (F _BM) were used to evaluate model performance. Contrast-enhanced T1 MR images from 195 patients with a total of 1034 BMs were solicited from our institutional stereotactic radiosurgery database. The patient cohort was split into training (160 patients, 809 lesions), validation (20 patients, 136 lesions), and testing (15 patients, 89 lesions) datasets. The lesions in the testing dataset were further divided into two subgroups based on the diameters (small S = 1-10 mm, large L = 11-26 mm). In the testing dataset, there were 72 and 17 BMs in the S and L sub-groups, respectively. Among all trained networks, asym-UNet achieved the highest DSC_v of 0.84 and lowest F _BM of 0.24. Although vanilla 3D-UNet with a single 1 × 1 × 3 kernel achieved the highest sensitivities for the S group, it resulted in the lowest precision and highest false detection rate. Asym-UNet was shown to balance sensitivity and false detection rate as well as keep the segmentation accuracy high. The novel asym-UNet segmentation network showed overall competitive segmentation performance and more pronounced improvement in hard-to-detect small BMs comparing to the vanilla single 3D UNet.

Treatment of Brain Metastases of Non-Small Cell Lung Carcinoma

Lung cancer is one of the most common malignant neoplasms. As a result of the disease's progression, patients may develop metastases to the central nervous system. The prognosis in this location is unfavorable; untreated metastatic lesions may lead to death within one to two months. Existing therapies-neurosurgery and radiation therapy-do not improve the prognosis for every patient. The discovery of Epidermal Growth Factor Receptor (EGFR)-activating mutations and Anaplastic Lymphoma Kinase (ALK) rearrangements in patients with non-small cell lung adenocarcinoma has allowed for the introduction of small-molecule tyrosine kinase inhibitors to the treatment of advanced-stage patients. The Epidermal Growth Factor Receptor (EGFR) is a transmembrane protein with tyrosine kinase-dependent activity. EGFR is present in membranes of all epithelial cells. In physiological conditions, it plays an important role in the process of cell growth and proliferation. Binding the ligand to the EGFR causes its dimerization and the activation of the intracellular signaling cascade. Signal transduction involves the activation of MAPK, AKT, and JNK, resulting in DNA synthesis and cell proliferation. In cancer cells, binding the ligand to the EGFR also leads to its dimerization and transduction of the signal to the cell interior. It has been demonstrated that activating mutations in the gene for EGFR-exon19 (deletion), L858R point mutation in exon 21, and mutation in exon 20 results in cancer cell proliferation. Continuous stimulation of the receptor inhibits apoptosis, stimulates invasion, intensifies angiogenesis, and facilitates the formation of distant metastases. As a consequence, the cancer progresses. These activating gene mutations for the EGFR are present in 10-20% of lung adenocarcinomas. Approximately 3-7% of patients with lung adenocarcinoma have the echinoderm microtubule-associated protein-like 4 (EML4)/ALK fusion gene. The fusion of the two genes EML4 and ALK results in a fusion gene that activates the intracellular signaling pathway, stimulates the proliferation of tumor cells, and inhibits apoptosis. A new group of drugs-small-molecule tyrosine kinase inhibitors-has been developed; the first generation includes gefitinib and erlotinib and the ALK inhibitor crizotinib. These drugs reversibly block the EGFR by stopping the signal transmission to the cell. The second-generation tyrosine kinase inhibitor (TKI) afatinib or ALK inhibitor alectinib block the receptor irreversibly. Clinical trials with TKI in patients with non-small cell lung adenocarcinoma with central nervous system (CNS) metastases have shown prolonged, progression-free survival, a high percentage of objective responses, and improved quality of life. Resistance to treatment with this group of drugs emerging during TKI therapy is the basis for the detection of resistance mutations. The T790M mutation, present in exon 20 of the EGFR gene, is detected in patients treated with first- and second-generation TKI and is overcome by Osimertinib, a third-generation TKI. The I117N resistance mutation in patients with the ALK mutation treated with alectinib is overcome by ceritinib. In this way, sequential therapy ensures the continuity of treatment. In patients with CNS metastases, attempts are made to simultaneously administer radiation therapy and tyrosine kinase inhibitors. Patients with lung adenocarcinoma with CNS metastases, without activating EGFR mutation and without ALK rearrangement, benefit from immunotherapy. This therapeutic option blocks the PD-1 receptor on the surface of T or B lymphocytes or PD-L1 located on cancer cells with an applicable antibody. Based on clinical trials, pembrolizumab and all antibodies are included in the treatment of non-small cell lung carcinoma with CNS metastases.

Treatment Options for Leptomeningeal Metastases of Solid Cancers: Literature Review and Personal Experience

Leptomeningeal metastases (LM) may complicate the clinical course of any solid cancer or hematological malignancy. Diagnosis of such cases requires a multifaceted approach, including careful evaluation of the clinical history, detailed neurological examination, advanced imaging studies, and related laboratory data analysis. Therapeutic options for management of LM have not been standardized yet. Conventional intrathecal chemotherapy with or without involved-field fractionated radiotherapy has only modest efficacy, and the prognosis of most patients remains grim. Therefore, development of new, more aggressive multimodal treatment strategies is definitely needed. Immune checkpoint inhibitors-in particular, molecular targeted therapy-have demonstrated promising results in selected groups of patients. There may be an important role for stereotactic radiosurgery as well. Because organization of prospective randomized multi-institutional trials on treatment of LM of solid cancers may be problematic, practical guidelines for optimal therapeutic strategies in such cases should be established on the basis of integrated results of small-scale prospective and retrospective studies.

Stereotactic radiosurgery optimization with hippocampal-sparing in patients treated for brain metastases

BACKGROUND AND PURPOSE

Cranial irradiation is associated with significant neurocognitive sequelae, secondary to radiation-induced damage to hippocampal cells. It has been shown that hippocampal-sparing (HS) leads to modest benefit in neurocognitive function in patients with brain metastases, but further improvement is possible. We hypothesized that improved benefits could be seen using HS in patients treated with stereotactic radiation (HS-SRS). Our study evaluated whether the hippocampal dose could be significantly reduced in the treatment of brain metastases using SRS, while maintaining target coverage.

MATERIALS AND METHODS

Sixty SRS plans were re-planned to minimize dose to the hippocampus while maintaining target coverage. Patients with metastases within 5 mm of the hippocampus were excluded. Minimum, mean, maximum and dose to 40% (mean equivalent dose in 2 Gy per fraction, EQD2 to the hippocampus) were compared between SRS and HS-SRS plans. Median number of brain metastases was two.

RESULTS

Compared to baseline SRS plans, hippocampal-sparing plans demonstrated Dmin was reduced by 35%, from 0.4 Gy to 0.3 Gy (p-value 0.02). Similarly, Dmax was reduced by 55%, from 8.2 Gy to 3.6 Gy, Dmean by 52%, from 1.6 Gy to 0.5 Gy, and D40 by 50%, from 1.8 Gy to 0.9 Gy (p-values <0.001).

CONCLUSIONS

Our study demonstrated that further reduction of hippocampal doses of more than 50% is possible in the treatment of brain metastases with SRS using dose optimization. This could result in significantly improved neurocognitive outcomes for patients treated for brain metastases.

Tumor Control Probability of Radiosurgery and Fractionated Stereotactic Radiosurgery for Brain Metastases

PURPOSE

As part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy, tumor control probability (TCP) after stereotactic radiosurgery (SRS) and fractionated stereotactic radiosurgery (fSRS) for brain metastases was modeled based on pooled dosimetric and clinical data from published English-language literature.

METHODS AND MATERIALS

PubMed-indexed studies published between January 1995 and September 2017 were used to evaluate dosimetric and clinical predictors of TCP after SRS or fSRS for brain metastases. Eligible studies had ≥10 patients and included detailed dose-fractionation data with corresponding ≥1-year local control (LC) data, typically evaluated as a >20% increase in diameter of the targeted lesion using the pre-SRS diameter as a reference.

RESULTS

Of 2951 potentially eligible manuscripts, 56 included sufficient dose-volume data for analyses. Accepting that necrosis and pseudoprogression can complicate the assessment of LC, for tumors ≤20 mm, single-fraction doses of 18 and 24 Gy corresponded with >85% and 95% 1-year LC rates, respectively. For tumors 21 to 30 mm, an 18 Gy single-fraction dose was associated with 75% LC. For tumors 31 to 40 mm, a 15 Gy single-fraction dose yielded ∼69% LC. For 3- to 5-fraction fSRS using doses in the range of 27 to 35 Gy, 80% 1-year LC has been achieved for tumors of 21 to 40 mm in diameter.

CONCLUSIONS

TCP for SRS and fSRS are presented. For small lesions ≤20 mm, single doses of ≈18 Gy appear generally associated with excellent rates of LC; for melanoma, higher doses seem warranted. For larger lesions >20 mm, local control rates appear to be ≈ 70% to 75% with usual doses of 15 to 18 Gy, and in this setting, fSRS regimens should be considered. Greater consistency in reporting of dosimetric and LC data is needed to facilitate future pooled analyses. As systemic and biologic therapies evolve, updated analyses will be needed to further assess the necessity, efficacy, and toxicity of SRS and fSRS.

Internal dose escalation associated with increased local control for melanoma brain metastases treated with stereotactic radiosurgery

OBJECTIVE

The internal high-dose volume varies widely for a given prescribed dose during stereotactic radiosurgery (SRS) to treat brain metastases (BMs). This may be altered during treatment planning, and the authors have previously shown that this improves local control (LC) for non-small cell lung cancer BMs without increasing toxicity. Here, they seek to identify potentially actionable dosimetric predictors of LC after SRS for melanoma BM.

METHODS

The records of patients with unresected melanoma BM treated with single-fraction Gamma Knife RS between 2006 and 2017 were reviewed. LC was assessed on a per-lesion basis, defined as stability or a decrease in lesion size. Outcome-oriented approaches were utilized to determine optimal dichotomization for dosimetric variables relative to LC. Univariable and multivariable Cox regression analysis was implemented to evaluate the impact of collected parameters on LC.

RESULTS

Two hundred eighty-seven melanoma BMs in 79 patients were identified. The median age was 56 years (range 31-86 years). The median follow-up was 7.6 months (range 0.5-81.6 months), and the median survival was 9.3 months (range 1.3-81.6 months). Lesions were optimally stratified by volume receiving at least 30 Gy (V30) greater than or equal to versus less than 25%. V30 was ≥ and < 25% in 147 and 140 lesions, respectively. For all patients, 1-year LC was 83% versus 66% for V30 ≥ and < 25%, respectively (p = 0.001). Stratifying by volume, lesions 2 cm or less (n = 215) had 1-year LC of 82% versus 70% (p = 0.013) for V30 ≥ and < 25%, respectively. Lesions > 2 to 3 cm (n = 32) had 1-year LC of 100% versus 43% (p = 0.214) for V30 ≥ and < 25%, respectively. V30 was still predictive of LC even after controlling for the use of immunotherapy and targeted therapy. Radionecrosis occurred in 2.8% of lesions and was not significantly associated with V30.

CONCLUSIONS

For a given prescription dose, an increased internal high-dose volume, as indicated by measures such as V30 ≥ 25%, is associated with improved LC but not increased toxicity in single-fraction SRS for melanoma BM. Internal dose escalation is an independent predictor of improved LC even in patients receiving immunotherapy and/or targeted therapy. This represents a dosimetric parameter that is actionable at the time of treatment planning and warrants further evaluation.

Outcome of Patients with NSCLC and Brain Metastases Treated with Immune Checkpoint Inhibitors in a 'Real-Life' Setting

Simple Summary

We identified non-small cell lung cancer (NSCLC) patients with brain metastases who were treated with immune checkpoint inhibitors at Karolinska University Hospital, Sweden and University Hospital of Heraklion, Greece from 2016 to 2019. We analyzed intracranial efficacies in the patients who had not received local treatment for their brain metastases less than three months prior to the initiation of immune checkpoint inhibitors and had adequate radiological evaluation. We demonstrated that immune checkpoint inhibitors are active in NSCLC patients with brain metastases regardless of the presence of neurological symptoms. This is a novel finding since, until now, this patient group has irrefutably been underrepresented in clinical studies and there is a clear scarcity of data. The results of our analyses suggest that symptomatic patients with active brain metastases (BM) may be considered for immunotherapy in routine clinical practice as well as clinical trials.

Abstract

There is lack of data addressing the intracranial (IC) efficacy of immune checkpoint inhibitors (ICIs) on brain metastases (BM) in non-small cell lung cancer (NSCLC). This patient category is underrepresented in randomized clinical trials. We retrospectively collected clinical data on patients with non-oncogenic driven NSCLC with BM who were treated with ICIs at two medical oncology institutes in Sweden and Greece from 2016 to 2019. IC efficacy was assessed in patients who had not received local treatment for BM less than three months prior to the initiation of ICIs and had adequate radiological evaluation. We screened 280 patients, of which 51 had BM. BM was an independent predictor for inferior PFS (HR = 2.27; 95% CI, 1.53–3.36) but not OS (HR = 1.58; 95% CI, 0.97–2.60) for the whole patient population. IC response assessment was done on 33 patients. IC objective response rate (ORR) was 24.2%. The presence of neurological symptoms related to BM did not affect IC ORR (p = 0.48). High PD-L1 levels from extracranial biopsies were not a predictive factor for IC ORR (p = 0.13). ICIs are active in NSCLC patients with BM regardless of the presence of neurological symptoms and can achieve durable IC disease stabilization in a subgroup of patients.

Significant correlation between gross tumor volume (GTV) D98% and local control in multifraction stereotactic radiotherapy (MF-SRT) for unresected brain metastases

BACKGROUND

Stereotactic radiotherapy (SRT) should be applied with a biologically effective dose with an α/β of 12 (BED₁₂) ≥ 40 Gy to reach a 1-year local control (LC) ≥ 70%. The aims of this retrospective study were to report a series of 81 unresected large brain metastases treated with Linac-based multifraction SRT according to the ICRU 91 and to identify predictive factors associated with LC.

METHODS

Included in this study were the first 81 brain metastases (BM) consecutively treated with Linac-based volumetric modulated arc therapy (VMAT) multifraction SRT from 2017 to 2019. The prescribed dose was 33 Gy for the GTV and 23.1 Gy (70% isodose line) for the PTV in 3 fractions (3f). Mean BM largest diameter and GTV were 25.1 mm and 7.2 cc respectively. Mean follow-up was 10.2 months.

RESULTS

LC was 79.7% and 69.7% at 1 and 2 years respectively. Significant predictive factors of LC were GTV D_98% (HR = 0.84, CI 95% = 0.75-0.95, p = 0.004) and adenocarcinoma as the histological type (HR = 0.29, CI 95% = 0.09-0.96, p = 0.042) in univariate and multivariate analysis. A threshold of 29 Gy for GTV D_98% was significantly correlated to LC (1-year LC = 91.9% for GTV D_98% ≥ 29 Gy vs 69.6% for GTV D_98% < 29 Gy (p = 0.030)), corresponding to a BED₁₂ = 52.4 Gy. No tumor progression was observed for a BED₁₂ ≥ 53.4 Gy, corresponding to a GTV D_98% ≥ 20 Gy /1f and GTV D_98% ≥ 29.4 Gy 3f. Median OS was 15 months. Symptomatic radionecrosis occurred in 4.9% of cases.

CONCLUSION

The GTV D_98% is a strong reproducible significant predictive factor of LC for brain SRT. Dose prescription should lead to a GTV BED_{12 98%} ≥ 52.4-53.4 Gy to significantly improve LC, corresponding to respectively a GTV D_98% ≥ 19.7-20 Gy/1f and 29-29.4 Gy/3f.

Application of targeted genome sequencing to brain metastasis from non-small cell lung carcinoma: Case report

Non-small cell lung cancer (NSCLC) is frequently associated with central nervous system metastases resulting in poor outcomes. As newer targeted therapies become available determining which patients can benefit from these therapies has remained challenging, and current molecular testing options rely on a panel of only a handful of known oncogenic drivers. Here, we demonstrate a targeted approach at uncovering clinically relevant variants in cancer-associated genes using genomic sequencing. Our patient underwent targeted sequencing of 212 cancer-associated genes, revealing mutations in six; two of which were in EGFR, an important target for therapy in NSCLC. A multidisciplinary approach involving surgical resection, radiation, and targeted therapy based on the genomic profile and tumor pathology ultimately lead to positive therapeutic response and stable disease. Our report provides a proof of principle for incorporating higher throughput genomic sequencing techniques directly into patient care. We also report an atypical response of an EGFR mutation positive metastatic tumor to immune checkpoint therapy, despite recent reports suggesting that these patients do not benefit from immune checkpoint inhibitors. A brief review of current literature is discussed here to explore links between EGFR mutations and PD-L1 expression, as well as response to targeted therapies.

Dosimetric feasibility of brain stereotactic radiosurgery with a 0.35 T MRI-guided linac and comparison vs a C-arm-mounted linac

PURPOSE

MRI is the gold-standard imaging modality for brain tumor diagnosis and delineation. The purpose of this work was to investigate the feasibility of performing brain stereotactic radiosurgery (SRS) with a 0.35 T MRI-guided linear accelerator (MRL) equipped with a double-focused multileaf collimator (MLC). Dosimetric comparisons were made vs a conventional C-arm-mounted linac with a high-definition MLC.

METHODS

The quality of MRL single-isocenter brain SRS treatment plans was evaluated as a function of target size for a series of spherical targets with diameters from 0.6 cm to 2.5 cm in an anthropomorphic head phantom and six brain metastases (max linear dimension = 0.7-1.9 cm) previously treated at our clinic on a conventional linac. Each target was prescribed 20 Gy to 99% of the target volume. Step-and-shoot IMRT plans were generated for the MRL using 11 static coplanar beams equally spaced over 360° about an isocenter placed at the center of the target. Couch and collimator angles are fixed for the MRL. Two MRL planning strategies (VR1 and VR2) were investigated. VR1 minimized the 12 Gy isodose volume while constraining the maximum point dose to be within ±1 Gy of 25 Gy which corresponded to normalization to an 80% isodose volume. VR2 minimized the 12 Gy isodose volume without the maximum dose constraint. For the conventional linac, the TB1 method followed the same strategy as VR1 while TB2 used five noncoplanar dynamic conformal arcs. Plan quality was evaluated in terms of conformity index (CI), conformity/gradient index (CGI), homogeneity index (HI), and volume of normal brain receiving ≥12 Gy (V_12Gy ). Quality assurance measurements were performed with Gafchromic EBT-XD film following an absolute dose calibration protocol.

RESULTS

For the phantom study, the CI of MRL plans was not significantly different compared to a conventional linac (P > 0.05). The use of dynamic conformal arcs and noncoplanar beams with a conventional linac spared significantly more normal brain (P = 0.027) and maximized the CGI, as expected. The mean CGI was 95.9 ± 4.5 for TB2 vs 86.6 ± 3.7 (VR1), 88.2 ± 4.8 (VR2), and 88.5 ± 5.9 (TB1). Each method satisfied a normal brain V_12Gy  ≤ 10.0 cm³ planning goal for targets with diameter ≤2.25 cm. The mean V_12Gy was 3.1 cm³ for TB2 vs 5.5 cm³ , 5.0 cm³ and 4.3 cm³ , for VR1, VR2, and TB1, respectively. For a 2.5-cm diameter target, only TB2 met the V_12Gy planning objective. The MRL clinical brain plans were deemed acceptable for patient treatment. The normal brain V_12Gy was ≤6.0 cm³ for all clinical targets (maximum target volume = 3.51 cm³ ). CI and CGI ranged from 1.12-1.65 and 81.2-88.3, respectively. Gamma analysis pass rates (3%/1mm criteria) exceeded 97.6% for six clinical targets planned and delivered on the MRL. The mean measured vs computed absolute dose difference was -0.1%.

CONCLUSIONS

The MRL system can produce clinically acceptable brain SRS plans for spherical lesions with diameter ≤2.25 cm. Large lesions (>2.25 cm) should be treated with a linac capable of delivering noncoplanar beams.

Impact of concomitant systemic treatments on toxicity and intracerebral response after stereotactic radiotherapy for brain metastases

Background

The aim of this study was to determine the safety and efficacy of fractionated stereotactic radiotherapy (SRT) in combination with systemic therapies (ST) for brain metastases (BM).

Methods

Ninety-nine patients (171 BM) received SRT and concurrent ST (group 1) and 95 patients (131 BM) received SRT alone without concurrent ST (group 2). SRT was planned on a linear accelerator, using volumetric modulated arc therapy. All ST were allowed including chemotherapy (CT), immunotherapy (IT), targeted therapy (TT) and hormonotherapy (HT). Treatment was considered to be concurrent if the timing between the drug administration and SRT did not exceed 1 month. Local control (LC), freedom for distant brain metastases (FFDBM), overall survival (OS) and radionecrosis (RN) were evaluated.

Results

After a median follow-up of 11.9 months (range 0.7–29.7), there was no significant difference between the two groups. However, patients who received concurrent IT (n = 30) had better 1-year LC, OS, FFDBM but a higher RN rate compared to patients who did not: 96% versus 78% (p = 0.02), 89% versus 77% (p = 0.02), 76% versus 53% (p = 0.004) and 80% versus 90% (p = 0.03), respectively. In multivariate analysis, concurrent IT (p = 0.022) and tumor volume < 2.07 cc (p = 0.039) were significantly correlated with improvement of LC. The addition of IT to SRT compared to SRT alone was associated with an increased risk of RN (p = 0.03).

Conclusion

SRT delivered concurrently with IT seems to be associated with improved LC, FFDBM and OS as well as with a higher rate of RN.

Initial Approach to Patients with a Newly Diagnosed Solitary Brain Metastasis

Solitary brain metastasis is defined by a single metastatic brain lesion as the only site of metastasis. The initial approach to this condition consists of radiographical evaluation to establish diagnosis, followed by assessment of functional and prognostic status. Neurologic symptom management consists of using dexamethasone and antiepileptic medications. Treatment consists of a combination of surgical and radiation therapy. Surgical treatment is indicated where there is a need for tissue diagnosis or immediate alleviation of neurologic symptoms and mass effect. Stereotactic radiosurgery has become an effective treatment modality. Whole-brain radiation therapy may have a role as an adjunctive therapy.

The Role of Stereotactic Radiosurgery in the Management of Brain Metastases From a Health-Economic Perspective: A Systematic Review

BACKGROUND

Stereotactic radiosurgery (SRS) is an effective option in the management of brain metastases, offering improved overall survival to whole-brain radiation therapy (WBRT). However, given the need for active surveillance and the possibility of repeated interventions for local/distant brain recurrences, the balance between clinical benefit and economic impact must be evaluated.

OBJECTIVE

To conduct a systematic review of health-economic analyses of SRS for brain metastases, compared with other existing intervention options, to determine the cost-effectiveness of this treatment across different clinical scenarios.

METHODS

The MEDLINE, EMBASE, Cochrane, CRD, and EconLit databases were searched for health-economic analyses, according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, using terms relevant to brain metastases and radiation-based therapies. Simple cost analysis studies were excluded. Quality analysis was based on BMJ Consolidated Health Economics Reporting Standards (CHEERS) checklist.

RESULTS

Eleven eligible studies were identified. For lesions with limited mass effect, SRS was more cost-effective than surgical resection (6 studies). In patients with Karnofsky performance scale (KPS) >70 and good predicted survival, SRS was cost-effective compared to WBRT (7 studies); WBRT became cost-effective with poor performance status or low anticipated life span. Following SRS, routine magnetic resonance imaging surveillance saved $1326/patient compared to symptomatic imaging due to reduced surgical salvage and hospital stay (1 study).

CONCLUSION

Based on our findings, SRS is cost-effective in the management of brain metastases, particularly in high-functioning patients with longer expected survival. However, before an optimal care pathway can be proposed, emerging factors such as tumor molecular subtype, diagnosis-specific graded prognostic assessment, neuroprognostic score, tailored surveillance imaging, and patient utilities need to be studied in greater detail.

The Clinical Characteristics of Endometrial Cancer With Extraperitoneal Metastasis and the Value of Surgery in Treatment

Objective:

To describe the clinical and pathological features of endometrial carcinoma with extraperitoneal metastasis and examine whether surgery could improve the prognosis.

Methods:

The Surveillance, Epidemiology, and End Results database was used to analyze 730 patients who were diagnosed with extraperitoneal metastasis of endometrial cancer from 2010 to 2015, including metastasis to the lung, bone, or brain.

Results:

Of the 730 patients, 372 (50.96%) patients had single lung metastases, and 196(26.85%) patients had multiple organ metastases that included pulmonary invasion. Therefore, the lung was the most common target organ for extraperitoneal metastasis of endometrial cancer. In multivariate risk factor analysis, grade 3 tumor (odds ratio = 3.39, P < .001), positive peritoneal cytology (odds ratio = 2.02, P < .001), and cervical stromal invasion (odds ratio = 1.42, P = .030) were independent risk factors for extraperitoneal metastasis. Once metastasis occurred in the brain or multiple organs, the prognosis was often poor. Of the patients, 362 underwent surgery, and surgery was performed only for primary tumors of the reproductive organs in almost all patients (97.23%) with extraperitoneal metastasis. The median cancer-specific survival periods of patients with solitary pulmonary metastasis undergoing surgery and those without surgery were 23 (16.43-29.57) months and 9 (6.21-11.79) months, respectively (P < .001), and survival superiority also existed in patients with bone metastasis (19 vs 8 months, P = .015) and multiple organs metastases (15 vs 4 months, P < .001). However, patients with brain metastasis had the same median survival period in the 2 groups (6 months, P = .146).

Conclusions:

The lung was the most common target organ for extraperitoneal metastasis in patients with endometrial cancer. Surgery was associated with improved survival in women with extraperitoneal metastasis, except for patients with brain metastasis.

Stereotactic irradiation of non-small cell lung cancer brain metastases: evaluation of local and cerebral control in a large series

Stereotactic radiotherapy (SRT) of brain metastases (BM) results are often reported in the heterogeneous primitive population. Here, we report our experience in consecutively treated patients who underwent SRT alone for BM from non-small cell lung cancer (NSCLC). This retrospective analysis included consecutive patients with no history of cerebral treatment who underwent Cyberknife™ SRT for BM from NSCLC in our institution from 2007 to 2016. One hundred patients were included in the study, with a median follow-up of 33 months (20–64). Mean age was 63 years (SD ± 10); 88% had Karnofsky Performance Status (KPS) > 70; 67% had unique BM; 18 patients received single-fraction SRT (20–25 Gy), and 82 received hypo-fractionated SRT (HSRT) (24–36 Gy in 3–5 fractions). We reported a complication rate of 17% (2% of G3-4). Median survival was 10.1 months [95% confidence interval (CI) 7.8–13.9]. At 1 year, local and cerebral control rates were respectively 78.7% (95% CI 70–86.5%) and 43% (95% CI 33.5–53%). Thirty patients underwent salvage treatment (whole brain radiation therapy, n = 13; SRT, n = 14; surgery, n = 3). Cyberknife™-based SRT is an effective treatment associated with high local control rate with low morbidity for patients with NSCLC’s BM. Close follow-up is necessary to perform salvage treatment.

Survival time and prognostic factors after whole-brain radiotherapy of brain metastases from of breast cancer

Background

Breast cancer has a poor prognosis due to the high risk of distant metastasis.

Purpose

To identify the prognosticators of brain metastasis from breast cancer treated by whole-brain radiotherapy.

Material and Methods

We evaluated patients diagnosed with primary brain metastasis without carcinomatous meningitis from breast cancer and had undergone whole-brain radiotherapy as initial treatment between 1 January 2010 and 30 September 2019. We investigated associations between overall survival time from diagnosis using cranial contrast-enhanced magnetic resonance imaging (MRI)/computed tomography (CT) and the following parameters: (i) age; (ii) sex; (iii) time to appearance of brain metastasis; (iv) other metastasis at appearance of brain metastasis; (v) blood test; (vi) symptoms at time of brain metastasis; (vii) whole-brain radiotherapy dose; (viii) whether whole-brain radiotherapy was completed; (ix) course of chemo- or radiotherapy; (x) subtype; (xi) additional irradiation after whole-brain radiotherapy; (xii) pathology; and (xiii) imaging findings.

Results

We evaluated 29 consecutive female patients (mean age 55.2 ± 12.1 years). Median overall survival time after diagnosis on cranial contrast-enhanced MRI/CT was 135 days (range 16–2112 days). Multivariate stepwise analysis of the three parameters of lactate dehydrogenase, dose, and subtype identified the following significant differences: Hazard Ratio (HR) for dose (discontinued, 30 Gy/10 fractions, 31.5 Gy/11 fractions, 32.5 Gy/11 fractions, 37.5 Gy/15 fractions) was 0.08 (95% confidence interval [CI] 0.02–0.30, P < 0.01), and HR for subtype (luminal, HER2, triple-negative) was 2.70 (95% CI 1.16–6.243, P < 0.01).

Conclusion

HER2-type and 37.5 Gy/15 fractions are good prognostic factor after whole-brain radiotherapy in breast cancer with brain metastases.

Evolving treatment strategies of brain metastases from breast cancer: current status and future direction

Remarkable progress in breast cancer treatment has improved patient survival, resulting in an increased incidence of brain metastasis (BM). Current treatment options for BM are limited and are generally used for palliative purposes. Historically, local treatment, consisting of radiotherapy and surgery, is the standard of care due to delivery limitations of systemic treatments through the blood-brain barrier. However, as novel biological mechanisms for tumors and BM have been discovered, several innovative systemic agents, such as small-molecular-targeted therapy and immunotherapy, have begun to change the treatment paradigm. In addition, efforts to maximize antitumor effects have been attempted using combination therapy, informed by tumor biology. In this comprehensive review, we will highlight various clinical trials investigating the treatment of BM in breast cancer patients, discuss presently available treatment options, and suggest potential directions of future therapeutic targets.

Case of a Long-Time Survivor with Recurrent Multiple Brain Metastases from Lung Cancer: Terminal Stage Cancer or Chronic Disease

Lung cancer with brain metastasis has a poor prognosis and has always been treated with palliative intent in the past. We report a case of good response to two courses of whole brain irradiation (WBI) and one course of hypofractionated stereotactic radiotherapy (HSRT) over a nine-year period, with no significant neurotoxicity. We present the case of a 43-year-old non-smoker female with biopsy-proven adenocarcinoma of right lower lobe lung, stage T1N2M0, positive for anaplastic lymphoma kinase (ALK). She received concurrent 60-Gy chemoradiation in 30 fractions in 2010. She had no local recurrence, but biopsy confirmed distant metastases in neck lymph nodes nine months later. As a result of a 3-cm brain metastasis in the right cerebellum on computed tomography (CT), she received 20-Gy WBI in five fractions. We did not treat any other distant metastases with radiation. She only received systemic tyrosine kinase inhibitors (TKIs). Four years after the first WBI, she developed headaches and balance problem. MRI showed at least nine metastatic lesions in the brain. She had a craniotomy to remove the largest 4-cm lesion in the right cerebellum followed by 21-Gy WBI in seven fractions. Her symptoms disappeared, and she went back to her normal life. Another MRI three years after the second WBI showed progression of the largest brain metastases in the right cerebellum. We offered her 20-Gy HSRT in five fractions every other day. She tolerated HSRT very well, with no neurotoxicity. She was able to walk without a walker or cane. She could manage all her daily activities. On examination, there was no neurological deficit. CT scan nine months after HSRT showed excellent local control.  Stage 4 non-small cell lung cancer with positive ALK can have a good response to TKI, and long survival is possible even with multiple brain metastases. Not all patients will have severe neurotoxicity after multiple courses of WBI. HSRT can be a good alternative treatment to symptomatic brain metastases if craniotomy is not desirable. The acute and late toxicities can be reasonably tolerated. Long-term local control and good quality of life are achievable.

Computational Modeling of Interstitial Fluid Pressure and Velocity in Non-small Cell Lung Cancer Brain Metastases Treated With Stereotactic Radiosurgery

Background: Early imaging-based treatment response assessment of brain metastases following stereotactic radiosurgery (SRS) remains challenging. The aim of this study is to determine whether early (within 12 weeks) intratumoral changes in interstitial fluid pressure (IFP) and velocity (IFV) estimated from computational fluid modeling (CFM) using dynamic contrast-enhanced (DCE) MRI can predict long-term outcomes of lung cancer brain metastases (LCBMs) treated with SRS.

Methods: Pre- and post-treatment T₁-weighted DCE-MRI data were obtained in 41 patients treated with SRS for intact LCBMs. The imaging response was assessed using RANO-BM criteria. For each lesion, extravasation of contrast agent measured from Extended Tofts pharmacokinetic Model (volume transfer constant, K^trans) was incorporated into a computational fluid model to estimate tumor IFP and IFV. Estimates of mean IFP and IFV and heterogeneity (skewness and kurtosis) were calculated for each lesion from pre- and post-SRS imaging. The Wilcoxon rank-sum test was utilized to assess for significant differences in IFP, IFV, and IFP/IFV change (Δ) between response groups.

Results: Fifty-three lesions from 41 patients were included. Median follow-up time after SRS was 11 months. The objective response (OR) rate (partial or complete response) was 79%, with 21% demonstrating stable disease (SD) or progressive disease (PD). There were significant response group differences for multiple posttreatment and Δ CFM parameters: post-SRS IFP skewness (mean −0.405 vs. −0.691, p = 0.022), IFP kurtosis (mean 2.88 vs. 3.51, p = 0.024), and IFV mean (5.75e-09 vs. 4.19e-09 m/s, p = 0.027); and Δ IFP kurtosis (mean −2.26 vs. −0.0156, p = 0.017) and IFV mean (1.91e-09 vs. 2.38e-10 m/s, p = 0.013). Posttreatment and Δ thresholds predicted non-OR with high sensitivity (sens): post-SRS IFP skewness (−0.432, sens 84%), kurtosis (2.89, sens 84%), and IFV mean (4.93e-09 m/s, sens 79%); and Δ IFP kurtosis (−0.469, sens 74%) and IFV mean (9.90e-10 m/s, sens 74%).

Conclusions: Objective response was associated with lower post-treatment tumor heterogeneity, as represented by reductions in IFP skewness and kurtosis. These results suggest that early post-treatment assessment of IFP and IFV can be used to predict long-term response of lung cancer brain metastases to SRS, allowing a timelier treatment modification.

Outcomes following stereotactic radiosurgery for small to medium-sized brain metastases are exceptionally dependent upon tumor size and prescribed dose

BACKGROUND

At our institution, we have historically treated brain metastasis (BM) ≤2 cm in eloquent brain with a radiosurgery (SRS) lower prescription dose (PD) to reduce the risk of radionecrosis (RN). We sought to evaluate the impact of this practice on outcomes.

METHODS

We analyzed a prospective registry of BM patients treated with SRS between 2008 and 2017. Incidences of local failure (LF) and RN were determined and Cox regression was performed for univariate and multivariate analyses (MVAs).

RESULTS

We evaluated 1533 BM ≤2 cm. Median radiographic follow-up post SRS was 12.7 months (1.4-100). Overall, the 2-year incidence of LF was lower for BM treated with PD ≥21 Gy (9.3%) compared with PD ≤15 Gy (19.5%) (sub-hazard ratio, 2.3; 95% CI: 1.4-3.7; P = 0.0006). The 2-year incidence of RN was not significantly higher for the group treated with PD ≥21 Gy (9.5%) compared with the PD ≤15 Gy group (7.5%) (P = 0.16). MVA demonstrated that PD (≤15 Gy) and tumor size (>1 cm) were significantly correlated (P < 0.05) with higher rates of LF and RN, respectively. For tumors ≤1 cm, when comparing PD ≤15 Gy with ≥21 Gy, the risks of LF and RN are equivalent. However, for lesions >1 cm, PD ≥21 Gy is associated with a lower incidence of LF without significantly increasing the risk of RN.

CONCLUSION

Our results indicate that rates of LF or RN following SRS for BM are strongly correlated with size and PD. Based on our results, we now, depending upon the clinical context, consider increasing PD to 21 Gy for BM in eloquent brain, excluding the brainstem.

Stereotactic radiosurgery in the treatment of adults with metastatic brain tumors

Brain metastasis is the most common type of intracranial tumor affecting a significant proportion of advanced cancer patients. In recent years, stereotactic radiosurgery (SRS) has become commonly utilized. It has contributed significantly to decreased toxicity, prolonged quality of life and general improvement in outcomes of patients with brain metastases. Frequent imaging and advanced treatment techniques have allowed for the treatment of more patients with large and numerous metastases extending their overall survival. The addition of targeted therapy and immunotherapy to SRS has introduced novel treatment paradigms and has further improved our ability to effectively treat brain lesions. In this review, we examined in detail the available evidence for the use of SRS alone or in combination with surgery and systemic therapies. Given our developing understanding of the importance of primary tumor histology, the use of different treatment strategies for different metastasis is evolving. Combining SRS with immunotherapy and targeted therapy in breast cancer, lung cancer and melanoma as well as the use of preoperative SRS have shown significant promise in recent years and are investigated in multiple ongoing prospective trials. Further research is needed to guide the optimal sequence of therapies and to identify specific patient subgroups that may benefit the most from aggressive, combined treatment approaches.

Radiomics Method for the Differential Diagnosis of Radionecrosis Versus Progression after Fractionated Stereotactic Body Radiotherapy for Brain Oligometastasis

Stereotactic radiotherapy (SRT) is recommended for treatment of brain oligometastasis (BoM) in patients with controlled primary disease. Where contrast enhancement enlargement occurs during follow-up, distinguishing between radionecrosis and progression presents a critical challenge. Without pathological confirmation, decision-making may be inappropriate and delayed. Quantitative imaging features extracted from routinely performed examinations are of interest in potentially addressing this problem. We explored the added value of the radiomics method for the differential diagnosis of these two entities. Twenty patients who received SRT for BoM, from any primary location, were included (8 radionecrosis, 12 progressions, pathologically confirmed). We assessed the clinical relevance of 1,766 radiomics features, extracted using IBEX software, from the first T1-weighted postcontrast magnetic resonance imaging (MRI) after SRT showing a lesion modification. We evaluated seven feature-selection methods and 12 classification methods in terms of respective predictive performance. The classification accuracy was measured using Cohen's kappa after leave-one-out cross-validation. In this work, the best predictive power reached was a Cohen's kappa of 0.68 (overall accuracy of 85%), expressing a strong agreement between the algorithm prediction and the histological gold standard. Prediction accuracy was 75% for radionecrosis, and 91% for progression. The area under a curve reached 0.83 using a bagging algorithm trained with the chi-square score features set. These findings indicated that the radiomics method is able to discriminate radionecrosis from progression in an accurate, early and noninvasive way. This promising study is a proof of concept, preceding a larger prospective study for defining a robust model to support decision-making in BoM. In summary, distinguishing between radionecrosis and progression is challenging without pathology. We built a classification model based on imaging data and machine learning. Using this model, we were able predict progression and radionecrosis in, respectively, 91% and 75% of cases.

Brain metastasis formation and irradiation by stereotactic radiation therapy combined with immunotherapy: A systematic review

INTRODUCTION

Brain metastasis (BM) is a complex process that implies immune cells and microglia. Stereotactic radiation therapy (SRT) and immunotherapy (IT) are established to increase the immune response; but their association has never been prospectively studied.

MATERIALS AND METHODS

Two reviewers performed a systematic review in original papers published up to September 2019. We analysed OS, local (mLRF) and regional (mBRF) median disease-free survival in patients with BMs after SRT with and without IT.

RESULTS

Upon 14 studies, eleven concerned melanoma, three concerned lung cancers. SRT-IT showed better OS, mLRF and mBRF than SRT. mBRF was better if SRT was performed with short delay from IT. No higher rates of radionecrosis and haemorrhage were found among groups.

CONCLUSION

This review suggests SRT combined to IT in melanoma is safe and could provide better BRF, suggesting a lymphocytic immune reaction in brain. No improvement trend was found in lung cancer BM.

Treating Brain Metastases from Breast Cancer: Outcomes after Stereotactic Radiosurgery

AIMS

Stereotactic radiosurgery (SRS) is an alternative to surgery or whole brain radiotherapy for the control of single or multiple brain metastases in patients with breast cancer. To date, there is no clear consensus on factors that might predict overall survival following SRS. The aim of this study was to assess the overall survival of breast cancer patients with brain metastases treated with SRS at a single centre and to examine the factors that might influence survival.

MATERIALS AND METHODS

A retrospective analysis of consecutive patients with breast cancer and brain metastases, considered suitable for SRS by the regional neuro-oncology multidisciplinary team. All patients were treated at a single National Health Service centre.

RESULTS

In total, 91 patients received SRS between 2013 and 2017, of whom 15 (16.5%) were alive at the time of analysis. The median overall survival post-SRS was 15.7 months (interquartile range 7.7-23.8 months) with no significant effect of age on survival (67 patients ≤ 65 years, 16.3 months; 26 patients > 65 years, 11.4 months, P = 0.129). The primary tumour receptor status was an important determinant of outcome: 31 oestrogen receptor positive (ER+)/human epidermal growth factor receptor 2 negative (HER2-) patients had a median overall survival of 13.8 months, 14 ER+/HER2+ patients had a median overall survival of 21.4 months, 30 ER-/HER2+ patients had a median overall survival of 20.4 months and 16 patients with triple negative breast cancer (TNBC) had a median overall survival of 8.5 months. A larger total volume of tumour treated (>10 cm³), but not the number of individual metastases treated, was associated with worse survival (P = 0.0002) in this series. Patients with stable extracranial disease at the time of SRS had improved overall survival compared with those with progressive extracranial disease (30 patients stable extracranial disease overall survival = 20.1 months versus 33 patients progressive extracranial disease overall survival = 11.4 months; P = 0.0011). Seventeen patients had no extracranial disease at the time of SRS, with a median overall survival of 13.1 months.

CONCLUSIONS

This single-centre series of consecutive patients with brain metastases from breast cancer, treated with SRS, had a similar overall survival compared with previous studies of SRS. TNBC and ER+/HER2- histology, metastatic volumes >10 cm³ and progressive extracranial disease at the time of SRS were associated with worse survival.

Management of brain metastases in breast cancer: a review of current practices and emerging treatments

PURPOSE

Breast cancer brain metastases (BCBM) are becoming an increasingly common diagnosis due to improved systemic control and more routine surveillance imaging. Treatment continues to require a multidisciplinary approach managing systemic and intracranial disease burden. Although, improvements have been made in the diagnosis and management of BCBM, brain metastasis patients continue to pose a challenge for practitioners.

METHODS

In this review, a group of medical oncologists, radiation oncologists, radiologists, breast surgeons, and neurosurgeons specializing in the treatment of breast cancer reviewed the available published literature and compiled a comprehensive review on the current state of BCBM.

RESULTS

We discuss the pathogenesis, epidemiology, diagnosis, treatment options (including systemic, surgical, and radiotherapy treatment modalities), and treatment response evaluation for BCBM. Furthermore, we discuss the ongoing prospective trials enrolling BCBM patients and their biologic rationale.

CONCLUSIONS

BCBM management is an increasing clinical concern. Multidisciplinary management combining the strengths of surgical, systemic, and radiation treatment modalities with prospective trials incorporating knowledge from the basic and translational sciences will ultimately lead to improved clinical outcomes for BCBM patients.

Repeated stereotactic radiosurgery (SRS) using a non-coplanar mono-isocenter (HyperArc™) technique versus upfront whole-brain radiotherapy (WBRT): a matched-pair analysis

Stereotactic radiosurgery (SRS) is an effective treatment option for multiple brain metastases (BMs). Modern mono-isocentric techniques allow the delivery of multiple stereotactic courses, in the event of intracranial failure. Nevertheless, limited data on effectiveness and toxicity have been reported in comparison to WBRT. Aim of this retrospective matched-pair analysis was to compare patients affected by limited BMs treated with multiple SRS courses using a mono-isocentric, non-coplanar technique (HyperArc™, Varian Medical System) to upfront WBRT. One hundred and two patients accounting for 677 BMs were treated with HyperArc™. In case of further intracranial progression, 44 treatment courses of 201 metastases in 19 patients, were treated by subsequent HyperArc™ courses. This population was matched with 38 patients treated with WBRT. The median BMs number was 4 (range 2-10) for HyperArc™ and 5 (range 2-10) for WBRT. Overall survival (OS) and toxicity were evaluated. The median follow-up was 9 months (range 3-40 months). The median OS was not reached (range 5-22 months) for HyperArc™ patients and 8 months (range 3-40 months) for WBRT patients, while the 1-year OS was 77% and 34.6% for HyperArc™ and WBRT, respectively (p = 0.001; HR 4.77, 95% CI 1.62-14.00). There was one case of radionecrosis. HyperArc™ is an effective and safe technique for the treatment of multiple BMs. In selected cases of intracranial oligorecurrence, further subsequent courses can be safely delivered with the same technical approach. Moreover, in patients with a limited number of BMs, SRS showed an improved survival outcome when compared to WBRT.