The Rationale for Targeted Therapies and Stereotactic Radiosurgery in the Treatment of Brain Metastases

Predictive value of perilesional edema volume in melanoma brain metastasis response to stereotactic radiosurgery

BACKGROUND AND AIM

Stereotactic radiotherapy (SRT) is an established treatment for melanoma brain metastases (MBM). Recent evidence suggests that perilesional edema volume (PEV) might compromise the delivery and efficacy of radiotherapy to treat BM. This study investigated the association between SRT efficacy and PEV extent in MBM.

MATERIALS AND METHODS

This retrospective study reviewed medical records from January 2020 to September 2023. Patients with up to 5 measurable MBMs, intracranial disease per RANO/iRANO criteria, and on low-dose corticosteroids were included. MRI scans assessed baseline neuroimaging, with PEV analyzed using 3D Slicer. SRT plans were based on MRI-CT fusion, delivering 18-32.5 Gy in 1-5 fractions. Outcomes included intracranial objective response rate (iORR) and survival measures (L-iPFS and OS). Statistical analysis involved decision tree analysis and multivariable logistic regression, adjusting for clinical and treatment variables.

RESULTS

Seventy-two patients with 101 MBM were analyzed, with a mean age of 68.83 years. The iORR was 61.4%, with Complete Response (CR) in 21.8% and Partial Response (PR) in 39.6% of the treated lesions. PEV correlated with KPS, BRAF status, and treatment response. Decision tree analysis identified a PEV cutoff at 0.5 cc, with lower PEVs predicting better responses (AUC = 0.82 sensitivity: 86.7%, specificity:74.4%,). Patients with PEV ≥ 0.5 cc had lower response rates (iORR 44.7% vs. 63.8%, p < 0.001). Median OS was 9.4 months, with L-iPFS of 27 months. PEV significantly impacted survival outcomes.

CONCLUSIONS

A more extensive PEV was associated with a less favorable outcome to SRT in MBM.

Fractionated stereotactic radiotherapy of intracranial postoperative cavities after resection of brain metastases - Clinical outcome and prognostic factors

Background and Purpose

After surgical resection of brain metastases (BM), radiotherapy (RT) is indicated. Postoperative stereotactic radiosurgery (SRS) reduces the risk of local progression and neurocognitive decline compared to whole brain radiotherapy (WBRT). Aside from the optimal dose and fractionation, little is known about the combination of systemic therapy and postoperative fractionated stereotactic radiotherapy (fSRT), especially regarding tumour control and toxicity.

Methods

In this study, 105 patients receiving postoperative fSRT with 35 Gy in 7 fractions performed with Cyberknife were retrospectively reviewed. Overall survival (OS), local control (LC) and total intracranial brain control (TIBC) were analysed via Kaplan-Meier method. Cox proportional hazards models were used to identify prognostic factors.

Results

Median follow-up was 20.8 months. One-year TIBC was 61.6% and one-year LC was 98.6%. Median OS was 28.7 (95%-CI: 16.9-40.5) months. In total, local progression (median time not reached) occurred in 2.0% and in 20.4% radiation-induced contrast enhancements (RICE) of the cavity (after median of 14.3 months) were diagnosed. Absence of extracranial metastases was identified as an independent prognostic factor for superior OS (p = <0.001) in multivariate analyses, while a higher Karnofsky performance score (KPS) was predictive for longer OS in univariate analysis (p = 0.041). Leptomeningeal disease (LMD) developed in 13% of patients.

Conclusion

FSRT after surgical resection of BM is an effective and safe treatment approach with excellent local control and acceptable toxicity. Further prospective randomized trials are needed to establish standardized therapeutic guidelines.

Genomic Alterations Identification and Resistance Mechanisms Exploration of NSCLC With Central Nervous System Metastases Using Liquid Biopsy of Cerebrospinal Fluid: A Real-World Study

Background

Genomic profiling of cerebrospinal fluid (CSF) can be used to detect actionable mutations and guide clinical treatment of non-small cell lung cancer (NSCLC) patients with central nervous system (CNS) metastases. Examining the performance of CSF samples in real-world settings can confirm the potential of CSF genotyping for guiding therapy in clinical practice.

Patients and Methods

We included 1,396 samples from 970 NSCLC patients with CNS metastases in real-world settings. All samples underwent targeted next-generation sequencing of 1,021 cancer-relevant genes. In total, 100 CSF samples from 77 patients who had previously received targeted treatment were retrospectively analyzed to explore the mechanisms of TKI-resistance.

Results

For NSCLC patients with CNS metastases, CSF samples were slightly more often used for genomic sequencing in treated patients with only distant CNS metastases compared to other patients (10.96% vs. 0.81–9.61%). Alteration rates in CSF samples were significantly higher than those in plasma, especially for copy number variants (CNV). The MSAFs of CSF samples were significantly higher than those of plasma and tumor tissues (all p <0.001). Remarkably, detection rates of all actionable mutations and EGFR in CSF were higher than those in plasma samples of treated patients (all p <0.0001). For concordance between paired CSF and plasma samples that were simultaneously tested, the MSAF of the CSF was significantly higher than that of matched plasma cfDNA (p <0.001). From multiple comparisons, it can be seen that CSF better detects alterations compared to plasma, especially CNV and structural variant (SV) alterations. CSF cfDNA in identifying mutations can confer the reason for the limited efficacy of EGFR-TKIs for 56 patients (78.87%, 56/71).

Conclusions

This real-world large cohort study confirmed that CSF had higher sensitivity than plasma in identifying actionable mutations and showed high potential in exploring underlying resistance mechanisms. CSF can be used in genomics profiling to facilitate the broad exploration of potential resistance mechanisms for NSCLC patients with CNS metastases.

Outcomes of Hypofractionated Stereotactic Radiotherapy for Small and Moderate-Sized Brain Metastases: A Single-Institution Analysis

Background

Stereotactic radiosurgery (SRS) is the standard treatment for limited intracranial metastases. With the advent of frameless treatment delivery, fractionated stereotactic radiotherapy (FSRT) has become more commonly implemented given superior control and toxicity rates for larger lesions. We reviewed our institutional experience of FSRT to brain metastases without size restriction.

Methods

We performed a retrospective review of our institutional database of patients treated with FSRT for brain metastases. Clinical and dosimetric details were abstracted. All patients were treated in 3 or 5 fractions using LINAC-based FSRT, did not receive prior cranial radiotherapy, and had at least 6 months of MRI follow-up. Overall survival was estimated using the Kaplan–Meier method. Local failure and radionecrosis cumulative incidence rates were estimated using a competing risks model with death as the competing risk. Univariable and multivariable analyses using Fine and Gray’s proportional subdistribution hazards regression model were performed to determine covariates predictive of local failure and radionecrosis.

Results

We identified 60 patients and 133 brain metastases treated at our institution from 2016 to 2020. The most common histologies were lung (53%) and melanoma (25%). Most lesions were >1 cm in diameter (84.2%) and did not have previous surgical resection (88%). The median duration of imaging follow-up was 9.8 months. The median survival for the whole cohort was 20.5 months. The local failure at 12 months was 17.8% for all lesions, 22.1% for lesions >1 cm, and 13.7% for lesions ≤1 cm (p = 0.36). The risk of radionecrosis at 12 months was 7.1% for all lesions, 13.2% for lesions >1 cm, and 3.2% for lesions ≤1 cm (p = 0.15).

Conclusions

FSRT is safe and effective in the treatment of brain metastases of any size with excellent local control and toxicity outcomes. Prospective evaluation against single-fraction SRS is warranted for all lesion sizes.

Role of exosomal miRNAs in brain metastasis affected by radiotherapy

In oncogenesis and development of malignant tumor, microRNAs (miRNAs) regulate the complex gene expression associated with the tumor pathogenesis. Currently, only few studies have been conducted to identify miRNAs and the potential pathways involved in the pathogenesis of brain metastasis in patients who underwent radiotherapy, especially miRNAs in the plasma exosomes. Therefore, this study is aimed to use small RNA analysis to identify miRNAs and their potential target genes in plasma exosomes during the initiation and development of brain metastasis in patients who underwent radiotherapy. Using high-throughput sequencing technologies, we identified 35 differentially expressed miRNAs in patients with brain metastasis who had undergone radiotherapy. In annotation of miRNA targets, gene ontology enrichment analysis revealed that the targets of the differentially expressed miRNAs were significantly enriched in the regulation of cellular processes. Kyoto Encyclopedia of Genes and Genomes revealed that most of the miRNA targets were cancer-related, including genes involved in the mitogen-activated protein kinase signaling pathway, cancer-related pathways, phosphatidylinositol 3-kinase-protein kinase B signaling pathway, microtubule-associated protein kinase signaling pathway, Ras signaling pathway, regulation of the actin cytoskeleton, and axon guidance. In conclusion, this study provides a new perspective to understand the possible function of these miRNAs in the pathogenesis of brain metastasis. This was the first time that a pilot study identified plasma exosomal miRNAs in five patients with brain metastasis before and after radiotherapy. This study is the beginning; more specimen and further research are needed to explore the functional role of specific miRNAs and their potential as therapeutic targets for brain metastasis.

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.

Changing Hands: A Rising Role of the Tumor Surgeon in Teaching Sylvian Fissure Dissection

OBJECTIVE

The landscape of microneurosurgery has changed considerably over the past 2 decades, with a decline in indications for open surgery on cerebrovascular pathology and ever-increasing indications for open resection of brain tumors. This study investigated how these trends in case volume affected residents' training experiences in microsurgery and, specifically, Sylvian fissure dissection.

METHODS

Resident case logs were reviewed, identifying open cerebrovascular operations and craniotomies for tumor. Operations involving Sylvian fissure dissection were identified through operative reports. Changes in case number by resident were plotted over time, and linear regression was applied.

RESULTS

Among 23 chief residents, 3045 operations were identified, 1071 of which were for cerebrovascular pathology and 1974 for tumor. Open cerebrovascular experience decreased (P < 0.0001) while tumor volume remained unchanged (P = 0.221). The number of Sylvian fissure dissections per resident did not change over time overall (P = 0.583) or within cerebrovascular operations (P = 0.071). The number of Sylvian fissure dissections in tumor operations increased (P = 0.004). This effect was predominated by an increase in intraaxial tumors approached via Sylvian fissure dissection (P = 0.003). The proportion of Sylvian fissure dissections in tumor surgery increased from 15% in 2009 to 34% by 2019 (P = 0.003).

CONCLUSIONS

Residents are seeing an increasing proportion of their Sylvian fissure dissection experience during tumor operations. The distribution of this experience will continue to evolve as surgical indications change but suggests a growing role for tumor surgeons in resident training in microsurgery.

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.

Hypofractionated radiation therapy with versus without immune checkpoint inhibitors in patients with brain metastases: A meta-analysis

INTRODUCTION

The efficacy and safety of hypofractionated radiation therapy (HFRT) combined with immune checkpoint inhibitors (ICIs) in patients with brain metastases (BM) remain controversial. This meta-analysis was performed to compare the efficacy and safety of HFRT with and without ICIs in BM patients.

MATERIALS AND METHODS

PubMed, Embase, and Cochrane Library were searched up to 25 December 2018 for studies that compared the efficacy and safety of HFRT with and without ICIs in BM patients.

RESULTS

Twenty-four studies involving 2,365 patients were included in this analysis. Compared with those of HFRT without ICIs, the 6-month locoregional recurrence-free survival (LRFS) rate (P = 0.002), 6-month overall survival (OS) rate (P = 0.001), 1-year OS rate (P = 0.001), 2-year OS rate (P = 0.007), and median OS (mOS) (P < 0.001) were significantly improved in combined HFRT and ICI treatment. A trend toward improved 1-year LRFS rate (P = 0.392) and 3-year OS rate (P = 0.266) for the ICI arm was observed compared with the non-ICI arm, although there was no statistically significant difference between the two arms. No significant difference in toxicity was found between the two arms (radionecrosis: P = 0.361; BM hemorrhage: P = 0.738).

CONCLUSIONS

Compared with HFRT without ICIs, the combination of these two therapies improved efficacy but did not increase toxicity in patients with BM.

Early posttreatment assessment of MRI perfusion biomarkers can predict long-term response of lung cancer brain metastases to stereotactic radiosurgery

Background

Imaging criteria to evaluate the response of brain metastases to stereotactic radiosurgery (SRS) in the early posttreatment period remains a crucial unmet need. The aim of this study is to correlate early (within 12 wk) posttreatment perfusion MRI changes with long-term outcomes after treatment of lung cancer brain metastases with SRS.

Methods

Pre- and posttreatment perfusion MRI scans were obtained in patients treated with SRS for intact non-small cell lung cancer brain metastases. Time-dependent leakage (Ktrans), blood plasma volume (Vp), and extracellular extravascular volume (Ve) were calculated for each lesion. Patients were followed longitudinally with serial MRI until death, progression, or intervention (whole brain radiation or surgery).

Results

We included 53 lesions treated with SRS from 41 total patients. Median follow-up after treatment was 11 months. Actuarial local control at one year was 85%. Univariate analysis demonstrated a significant difference (P = 0.032) in posttreatment Ktrans SD between patients with progressive disease (mean = 0.0317) and without progressive disease (mean = 0.0219). A posttreatment Ktrans SD cutoff value of 0.017 was highly sensitive (89%) for predicting progressive disease and no progressive disease. Early posttreatment volume change was not associated with outcome (P = 0.941).

Conclusion

Posttreatment Ktrans SD may be used as an early posttreatment imaging biomarker to help predict long-term response of lung cancer brain metastases to SRS. This can help identify patients who will ultimately fail SRS and allow for timelier adjustment in treatment approach. These data should be prospectively validated in larger patient cohorts and other histologies.

Detectability of radiation-induced changes in magnetic resonance biomarkers following stereotactic radiosurgery: A pilot study

Our objective was to investigate direct voxel-wise relationship between dose and early MR biomarker changes both within and in the high-dose region surrounding brain metastases following stereotactic radiosurgery (SRS). Specifically, we examined the apparent diffusion coefficient (ADC) from diffusion-weighted imaging and the contrast transfer coefficient (K^trans) and volume of extracellular extravascular space (v_e) derived from dynamic contrast-enhanced (DCE) MRI data. We investigated 29 brain metastases in 18 patients using 3 T MRI to collect imaging data at day 0, day 3 and day 20 following SRS. The ADC maps were generated by the scanner and K^trans and v_e maps were generated using in-house software for dynamic tracer-kinetic analysis. To enable spatially-correlated voxel-wise analysis, we developed a registration pipeline to register all ADC, K^trans and v_e maps to the planning MRI scan. To interrogate longitudinal changes, we computed absolute ΔADC, ΔK^trans and Δv_e for day 3 and 20 post-SRS relative to day 0. We performed a Kruskall-Wallice test on each biomarker between time points and investigated dose correlations within the gross tumour volume (GTV) and surrounding high dose region > 12 Gy via Spearman’s rho. Only v_e exhibited significant differences between day 0 and 20 (p < 0.005) and day 3 and 20 (p < 0.05) within the GTV following SRS. Strongest dose correlations were observed for ADC within the GTV (rho = 0.17 to 0.20) and weak correlations were observed for ADC and K^trans in the surrounding > 12 Gy region. Both ΔK^trans and Δv_e showed a trend with dose at day 20 within the GTV and > 12 Gy region (rho = -0.04 to -0.16). Weak dose-related decreases in K^trans and v_e within the GTV and high dose region at day 20 most likely reflect underlying vascular responses to radiation. Our study also provides a voxel-wise analysis schema for future MR biomarker studies with the goal of elucidating surrogates for radionecrosis.

Cognitive effects of stereotactic radiosurgery in adult patients with brain metastases: A systematic review

PURPOSE

Stereotactic radiation surgery (SRS) is increasingly applied in patients with brain metastases (BM) and is expected to have fewer adverse effects on cognitive functioning than whole brain radiation therapy (WBRT). Patients with BM are often confronted with a relatively short life expectancy, and the prevention or delay of cognitive decline to maintain quality of life is a clinically and highly relevant treatment goal. This review systematically and specifically evaluates the current literature on the cognitive effects of SRS in patients with BM.

METHODS AND MATERIALS

Published trials on SRS alone or in combination with WBRT, including objective assessment of cognitive functioning, were identified through a systematic search of the PubMed database up to March 2018.

RESULTS

Of the 241 records screened, 14 studies matched the selection criteria: 2 pilot studies, 7 single-group/observational trials (1 study update), and 5 randomized trials (1 secondary analysis).

CONCLUSIONS

In general, the results show little to no objective cognitive decline up to 4 months after SRS compared with WBRT. However, most trials suffered from methodologic limitations that hindered reliable conclusions. Most importantly, few studies investigated the specific cognitive effects of SRS alone or versus WBRT. Furthermore, disentangling the cognitive effects of SRS from the effects of the disease itself and from the effects of other treatments remains very difficult. By presenting this comprehensive review, we aim to encourage researchers to probe deeper into this area and to do so in a standardized and methodologically optimal manner. The ultimate objective of this line of research is to inform both doctors and patients more precisely about the cognitive effects they can expect from treatment. This study is expected to improve the quality of decision-making and maximize clinical outcomes for each individual patient.

Epidemiology, Treatment, and Complications of Central Nervous System Metastases

PURPOSE OF REVIEW

Neurologic problems resulting from systemic cancer metastases to brain parenchyma, dura, spinal cord, and leptomeninges are among the most common types of consultations addressed by neurologists. With patients surviving longer from systemic cancer, along with the rapidly evolving therapeutic options, the treatment of these devastating complications has become both more effective and more complicated. This article reviews current patterns of metastatic disease and the increasingly nuanced landscape of evolving therapies, their complications, and their impact on quality of survival.

RECENT FINDINGS

Targeted therapies with tyrosine kinase inhibitors and immune checkpoint inhibitors and cytotoxic therapies directed at disease-specific chemosensitivity patterns have dramatically improved the prognosis of non-small cell lung cancer, melanoma, and breast cancer, but have led to some novel complications and altered recurrence patterns. Clinical trials suggest the superiority of hippocampal-avoidance radiation fields and the use of stereotactic radiosurgery over whole-brain radiation therapy to minimize long-term cognitive consequences of radiation therapy. Emerging data document tolerable safety when brain radiation is combined with immunotherapy. Chemotherapy can be a first-line treatment for some inoperable brain metastases, eliminating or deferring whole-brain radiation therapy. Stereotactic body radiation therapy is a new technique of radiation used for spinal and epidural metastases that spares spinal cord tissue while ablating tumors.

SUMMARY

Metastases to the nervous system remain devastating, but their prognosis and therapies are more heterogeneous than previously appreciated. Neurologists now can offer more personalized prognostic information based on new stratification criteria, can predict drug complications relevant to the nervous system, and can provide critical partnership in the multidisciplinary effort to balance effective longer-term disease control with treatment-related adverse consequences.

Brain metastases with poor vascular function are susceptible to pseudoprogression after stereotactic radiation surgery

Purpose

This study aimed to investigate the hemodynamic status of cerebral metastases prior to and after stereotactic radiation surgery (SRS) and to identify the vascular characteristics that are associated with the development of pseudoprogression from radiation-induced damage with and without a radionecrotic component.

Methods and materials

Twenty-four patients with 29 metastases from non-small cell lung cancer or malignant melanoma received SRS with dose of 15 Gy to 25 Gy. Magnetic resonance imaging (MRI) scans were acquired prior to SRS, every 3 months during the first year after SRS, and every 6 months thereafter. On the basis of the follow-up MRI scans or histology after SRS, metastases were classified as having response, tumor progression, or pseudoprogression. Advanced perfusion MRI enabled the estimation of vascular status in tumor regions including fractions of abnormal vessel architecture, underperfused tissue, and vessel pruning.

Results

Prior to SRS, metastases that later developed pseudoprogression had a distinct poor vascular function in the peritumoral zone compared with responding metastases (P < .05; number of metastases = 15). In addition, differences were found between the peritumoral zone of pseudoprogressing metastases and normal-appearing brain tissue (P < .05). In contrast, for responding metastases, no differences in vascular status between peritumoral and normal-appearing brain tissue were observed. The dysfunctional peritumoral vasculature persisted in pseudoprogressing metastases after SRS.

Conclusions

Our results suggest that the vascular status of peritumoral tissue prior to SRS plays a defining role in the development of pseudoprogression and that advanced perfusion MRI may provide new insights into patients' susceptibility to radiation-induced effects.

SRS in Combination With Ipilimumab: A Promising New Dimension for Treating Melanoma Brain Metastases

Stereotactic radiosurgery provides effective local control, but high recurrence rate are observed while ipilimumab have shown promising improvements in survival in the treatment of melanoma brain metastases. This meta-analysis was done to review the clinical evidence regarding the combination of stereotactic radiosurgery and ipilimumab in the treatment of brain metastases from melanoma. Comprehensive research of the electronic databases (PubMed and Cochrane Library) was carried out in April 2017. Different combination of MESH headings and words were used. Review Manager was used to analyze the outcome data of interest. According to heterogeneity, fixed effects model or random effects model was adapted. Six retrospective studies comparing stereotactic radiosurgery plus ipilimumab with stereotactic radiosurgery alone were found. Total of 411 participants were included in this meta-analysis. Of that, 128 patients had received stereotactic radiosurgery + ipilimumab, while 283 patients had received stereotactic radiosurgery only. Stereotactic radiosurgery plus ipilimumab significantly improved survival when compared to stereotactic radiosurgery alone (hazard ratio: 0.74 [95% confidence interval: 0.56-0.99, P = .04]), with no significant increase in the incidence of adverse events (odds ratio 0.57 [95% confidence interval: 0.28-1.17, P = .12]). Stereotactic radiosurgery with ipilimumab is safe and effective treatment option and can be recommended for the treatment of brain metastases in patients with melanoma.

Diagnosis and treatment of brain metastases from solid tumors: guidelines from the European Association of Neuro-Oncology (EANO)

The management of patients with brain metastases has become a major issue due to the increasing frequency and complexity of the diagnostic and therapeutic approaches. In 2014, the European Association of Neuro-Oncology (EANO) created a multidisciplinary Task Force to draw evidence-based guidelines for patients with brain metastases from solid tumors. Here, we present these guidelines, which provide a consensus review of evidence and recommendations for diagnosis by neuroimaging and neuropathology, staging, prognostic factors, and different treatment options. Specifically, we addressed options such as surgery, stereotactic radiosurgery/stereotactic fractionated radiotherapy, whole-brain radiotherapy, chemotherapy and targeted therapy (with particular attention to brain metastases from non-small cell lung cancer, melanoma and breast and renal cancer), and supportive care.

Radiotoxicity in robotic radiosurgery: proposing a new quality index for optimizing the treatment planning of brain metastases

BACKGROUND

As irradiated brain volume at 12 Gy (V12) is a predictor for radionecrosis, the purpose of the study was to develop a model for Cyberknife (CK) plans that is able to predict the lowest achievable V12 at a given tumor size and prescription dose (PD), and to suggest a new quality index regarding V12 for optimizing the treatment planning of brain metastases.

METHOD

In our model V12 was approximated as a spherical shell around the tumor volume. The radial distance between tumor surface and the 12 Gy isodose line was calculated using an approximation of the mean dose gradient in that area. Assuming a radially symmetrical irradiation from the upper half space, the dose distribution is given by the superposition of single fields. The dose profiles of a single field were derived by the measured off-center ratios (OCR) of the CK system. Using the calculated gradients of the sum dose profiles, minimal-V12 was estimated for different tumor sizes. The model calculation was tested using a phantom dataset and retrospectively applied on clinical cases.

RESULTS

Our model allows the prediction of a best-case scenario for V12 at a given tumor size and PD which was confirmed by the results of the isocentric phantom plans. The results of the non-isocentric phantom plans showed that an optimization of coverage caused an increase in V12. This was in accordance with the results of the retrospective analysis. V12 s of the clinical cases were on average twice that of the predicted model calculation. A good agreement was achieved for plans with an optimal conformity index (nCI). Re-planning of cases with high V12 showed that lower values could be reached by selecting smaller collimators and by allowing a larger number of total MU and more MU per beam.

CONCLUSIONS

V12 is a main parameter for assessing plan quality in terms of radiotoxicity. The index f12 defined as the ratio of V12 from the actual plan with the evaluated V12 from our model describes the conformity of an optimally possible V12 and thus can be used as a new quality index for optimizing treatment plans.

Treatment of brain metastasis: current status and future directions

PURPOSE OF REVIEW

The purpose of this review is to highlight the most recent advances in the management of brain metastases.

RECENT FINDINGS

Role of local therapies (surgery and stereotactic radiosurgery), new approaches to minimize cognitive sequelae following whole-brain radiotherapy and advances in targeted therapies have been reviewed.

SUMMARY

The implications for clinical trials and daily practice of the increasing use of stereotactic radiosurgery in multiple brain metastases and upfront targeted agents in asymptomatic brain metastases are discussed.

Survival Patterns of 5750 Stereotactic Radiosurgery-Treated Patients with Brain Metastasis as a Function of the Number of Lesions

BACKGROUND

The number of brain metastases (BMs) plays an important role in the decision between stereotactic radiosurgery (SRS) and whole-brain radiation therapy.

METHODS

We analyzed the survival of 5750 SRS-treated patients with BM as a function of BM number. Survival analyses were performed with Kaplan-Meier analysis as well as univariate and multivariate Cox proportional hazards models.

RESULTS

Patients with BMs were first categorized as those with 1, 2-4, and 5-10 BMs based on the scheme proposed by Yamamoto et al. (Lancet Oncology 2014). Median overall survival for patients with 1 BM was superior to those with 2-4 BMs (7.1 months vs. 6.4 months, P = 0.009), and survival of patients with 2-4 BMs did not differ from those with 5-10 BMs (6.4 months vs. 6.3 months, P = 0.170). The median survival of patients with >10 BMs was lower than those with 2-10 BMs (6.3 months vs. 5.5 months, P = 0.025). In a multivariate model that accounted for age, Karnofsky Performance Score, systemic disease status, tumor histology, and cumulative intracranial tumor volume, we observed a ∼10% increase in hazard of death when comparing patients with 1 versus 2-10 BMs (P < 0.001) or 10 versus >10 BMs (P < 0.001). When BM number was modeled as a continuous variable rather than using the classification by Yamamoto et al., we observed a step-wise 4% increase in the hazard of death for every increment of 6-7 BM (P < 0.001).

CONCLUSIONS

The contribution of BM number to overall survival is modest and should be considered as one of the many variables considered in the decision between SRS and whole-brain radiation therapy.

Immunotherapy and radiation therapy for operable early stage and locally advanced non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common cause of cancer mortality. Although a significant proportion of patients can be cured with surgery, with or without adjuvant or neoadjuvant chemotherapy and radiation, a significant proportion of patients will fail, particularly distantly. Over fifty percent of patients present with stage IV disease. There are multiple forms of immunotherapy available including T-cell transfer, cytokine therapy, and oncolytic viruses. Checkpoint inhibitors have shown tremendous activity in NSCLC and are currently under intense study given promising data on response. Immunotherapy and radiation therapy (RT) both show significant immune editing activity in NSCLC that may allow the innate and adaptive immune system to help control systemic disease by both radiosensitization and a sustained systemic immune response. Multiple clinical trials are underway exploring the role of adjuvant or neoadjuvant immunotherapy in operable NSCLC. A substantial amount of progress is to be made in terms of optimizing radiation dose and fractionation, immunotherapy type and dose, and integrating both to best realize the benefits of immunotherapy and radiation in operable lung cancer.

Combination of Radiotherapy and Targeted Agents in Brain Metastasis: An Update

OPINION STATEMENT

The combination of radiation therapy and targeted agents (molecular inhibitors or immunotherapy) represents an opportunity to improve the outcomes of patients with brain metastases. The combination of whole-brain radiation therapy (WBRT) with targeted agents takes advantage of radiosensitization, while the combination with stereotactic radiosurgery (SRS) may allow one to substitute an effective systemic agent for adjuvant WBRT, the historical standard of care. This strategy may in turn allow the promotion of secondary prevention paradigms with possibly less cognitive toxicity. At present, the combination of targeted therapy with SRS rather than with WBRT is the more viable option although both avenues will likely have a role in the future management of brain metastases. Patients should be encouraged to enter clinical trials since the off-study use of these combinations will delay the advancement of the field. Caution is advised in the combination of radiation and targeted agents as unexpected toxicities can occur. Clinicians should avail themselves of clinical trials in order to offer patients these promising options and to move the field forward. In the absence of a clinical trial, we recommend the combination of SRS with targeted agents and deferred WBRT. Small, asymptomatic brain metastases may be best managed with single-modality targeted agents with deferred radiation therapy, preferably on a clinical trial. Advances in targeted therapies combined with radiation therapy will most likely improve local control and hopefully the quality of life and survival of patients with brain metastasis.