Melanoma brain metastasis presentation, treatment, and outcomes in the age of targeted and immunotherapies

Melanoma Brain Metastasis: Biology and Therapeutic Advances

Metastasis to the brain is a frequent complication of advanced melanoma. Historically, patients with melanoma brain metastasis (MBM) have had dismal outcomes, but outcomes have improved with the development of more effective treatments, including stereotactic radiosurgery and effective immune and targeted therapies. Despite these advances, MBM remains a leading cause of death from this disease, and many therapies show decreased efficacy against these tumors compared with extracranial metastases. This differential efficacy may be because of recently revealed unique molecular and immune features of MBMs-which may also provide rational new therapeutic strategies.

"Symptomatic" melanoma brain metastases: A call for clear definitions and adoption of standardized tools

With improved systemic treatment and prolonged survival even with metastatic disease, diagnosing, treating, and monitoring brain metastases has become a central topic in the care of patients with melanoma. Patients with brain metastases from melanoma are typically excluded from pivotal clinical trials. When allowed, inclusion and exclusion criteria are rather selective and do not reflect the larger population of melanoma patients with brain metastases who frequently present with neurological symptoms and signs and require steroid medications. Moreover, the lack of consensus on reporting symptomatic brain involvement complicates the interpretation and implications of trial results for the overall population of patients with melanoma and brain metastasis. Here, we review the evidence regarding brain metastasis from melanoma and discuss the challenges of longitudinal neurological clinical assessments, including tools to capture cognition and quality of life. Finally, we propose the adoption of standardized tools to interpret neurological deficits in patients with melanoma and brain metastases and to assess the neurological status in the context of clinical trials.

Prevention of Brain Metastases: A New Frontier

This review discusses the topic of prevention of brain metastases from the most frequent solid tumor types, i.e., lung cancer, breast cancer and melanoma. Within each tumor type, the risk of brain metastasis is related to disease status and molecular subtype (i.e., EGFR-mutant non-small cell lung cancer, HER2-positive and triple-negative breast cancer, BRAF and NRAF-mutant melanoma). Prophylactic cranial irradiation is the standard of care in patients in small cell lung cancer responsive to chemotherapy but at the price of late neurocognitive decline. More recently, several molecular agents with the capability to target molecular alterations driving tumor growth have proven as effective in the prevention of secondary relapse into the brain in clinical trials. This is the case for EGFR-mutant or ALK-rearranged non-small cell lung cancer inhibitors, tucatinib and trastuzumab-deruxtecan for HER2-positive breast cancer and BRAF inhibitors for melanoma. The need for screening with an MRI in asymptomatic patients at risk of brain metastases is emphasized.

Upregulation of HLA-II related to LAG-3+CD4+ T cell infiltration is associated with patient outcome in human glioblastoma

Glioblastoma (GBM) is the most common malignant diffuse glioma of the brain. Although immunotherapy with immune checkpoint inhibitors (ICIs), such as programmed cell death protein (PD)-1/PD ligand-1 inhibitors, has revolutionized the treatment of several cancers, the clinical benefit in GBM patients has been limited. Lymphocyte-activation gene 3 (LAG-3) binding to human leukocyte antigen-II (HLA-II) plays an essential role in triggering CD4+ T cell exhaustion and could interfere with the efficiency of anti-PD-1 treatment; however, the value of LAG-3-HLA-II interactions in ICI immunotherapy for GBM patients has not yet been analyzed. Therefore, we aimed to investigate the expression and regulation of HLA-II in human GBM samples and the correlation with LAG-3+CD4+ T cell infiltration. Human leukocyte antigen-II was highly expressed in GBM and correlated with increased LAG-3+CD4+ T cell infiltration in the stroma. Additionally, HLA-IIHighLAG-3High was associated with worse patient survival. Increased interleukin-10 (IL-10) expression was observed in GBM, which was correlated with high levels of HLA-II and LAG-3+ T cell infiltration in stroma. HLA-IIHighIL-10High GBM associated with LAG-3+ T cells infiltration synergistically showed shorter overall survival in patients. Combined anti-LAG-3 and anti-IL-10 treatment inhibited tumor growth in a mouse brain GL261 tumor model. In vitro, CD68+ macrophages upregulated HLA-II expression in GBM cells through tumor necrosis factor-α (TNF-α). Blocking TNF-α-dependent inflammation inhibited tumor growth in a mouse GBM model. In summary, T cell-tumor cell interactions, such as LAG-3-HLA-II, could confer an immunosuppressive environment in human GBM, leading to poor prognosis in patients. Therefore, targeting the LAG-3-HLA-II interaction could be beneficial in ICI immunotherapy to improve the clinical outcome of GBM patients.

Symptomatic brain metastases in melanoma

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

Demographics aspects of brain and spine metastatic melanoma. Retrospective analysis in a single third-level center

Background

Melanoma metastases to the CNS rank third in frequency, just after lung and breast metastases. There is controversy regarding the factors predisposing to developing CNS metastases in patients with cutaneous melanoma and their survival with conventional treatments.

Methods

We carried out a retrospective analysis in a third-level hospital in Mexico to determine epidemiological aspects of melanoma metastases to the central nervous system, factors related to its appearance, clinical presentation, and survival in three treatment groups: surgery, radiotherapy, and conservative management.

Results

We found that the nodular variant has the most significant association with CNS metastases. In addition, the superficial spreading variant has the highest risk of presenting a more substantial number of lesions, up to seven for each case and predominantly in the infratentorial space. On the other hand, we found more remarkable survival in patients treated only with surgery than those treated with radiotherapy or conservatively.

Conclusions

This study lays the foundations for future prospective survival analysis of the different current treatment modalities for metastatic melanoma in the brain and spine. It also highlights the clinical risk factors for metastatic brain and spine tumors of melanoma.

Peripheral macrophages in the development and progression of structural cerebrovascular pathologies

The human cerebrovascular system is responsible for maintaining neural function through oxygenation, nutrient supply, filtration of toxins, and additional specialized tasks. While the cerebrovascular system has resilience imparted by elaborate redundant collateral circulation from supportive tertiary structures, it is not infallible, and is susceptible to developing structural vascular abnormalities. The causes of this class of structural cerebrovascular diseases can be broadly categorized as 1) intrinsic developmental diseases resulting from genetic or other underlying aberrations (arteriovenous malformations and cavernous malformations) or 2) extrinsic acquired diseases that cause compensatory mechanisms to drive vascular remodeling (aneurysms and arteriovenous fistulae). Cerebrovascular diseases of both types pose significant risks to patients, in some cases leading to death or disability. The drivers of such diseases are extensive, yet inflammation is intimately tied to all of their progressions. Central to this inflammatory hypothesis is the role of peripheral macrophages; targeting this critical cell type may lead to diagnostic and therapeutic advancement in this area. Here, we comprehensively review the role that peripheral macrophages play in cerebrovascular pathogenesis, provide a schema through which macrophage behavior can be understood in cerebrovascular pathologies, and describe emerging diagnostic and therapeutic avenues in this area.

Clinical outcomes of melanoma brain metastases treated with nivolumab and ipilimumab alone versus nivolumab and ipilimumab with stereotactic radiosurgery

PURPOSE

Upfront dual checkpoint blockade with immune checkpoint inhibitors (ICI) has demonstrated efficacy for treating melanoma brain metastases (MBM) in asymptomatic patients. Whether the combination of stereotactic radiosurgery (SRS) with dual checkpoint blockade improves outcomes over dual-checkpoint blockade alone is unknown. We evaluated clinical outcomes of patients with MBM receiving ICI with nivolumab and ipilimumab, with and without SRS.

METHODS

49 patients with 158 MBM receiving nivolumab and ipilimumab for untreated MBM between 2015 and 2022 were identified at our institution. Patient and tumor characteristics including age, Karnofsky Performance Status (KPS), presence of symptoms, cancer history, MBM burden, and therapy course were recorded. Outcomes measured from initiation of MBM-directed therapy included overall survival (OS), local control (LC), and distant intracranial control (DIC). Time-to-event analysis was conducted with the Kaplan-Meier method.

RESULTS

25 patients with 74 MBM received ICI alone, and 24 patients with 84 MBM received concurrent SRS. Median follow-up was 24 months. No differences in age (p = 0.96), KPS (p = 0.85), presence of symptoms (p = 0.79), prior MBM (p = 0.68), prior MBM-directed surgery (p = 0.96) or SRS (p = 0.68), MBM size (p = 0.67), or MBM number (p = 0.94) were seen. There was a higher rate of nivolumab and ipilimumab course completion in the SRS group (54% vs. 24%; p = 0.029). The SRS group received prior immunotherapy more often than the ICI alone group (54% vs. 8.0%; p < 0.001). There was no significant difference in 1-year OS (72% vs. 71%, p = 0.20) and DIC (63% v 51%, p = 0.26) between groups. The SRS group had higher 1-year LC (92% vs. 64%; p = 0.002). On multivariate analysis, LC was improved with combination therapy (AHR 0.38, p = 0.01).

CONCLUSION

In our analysis, patients who received SRS with nivolumab and ipilimumab had superior LC without increased risk of toxicity or compromised immunotherapy treatment completion despite the SRS cohort having higher rates of prior immunotherapy. Further prospective study of combination nivolumab and ipilimumab with SRS is warranted.

Effectiveness, safety and utilization of cobimetinib and vemurafenib in patients with BRAF V600 mutant melanoma with and without cerebral metastasis under real-world conditions in Germany: the non-interventional study coveNIS

Cobimetinib/vemurafenib combination therapy is approved for treatment of adults with unresectable or metastatic BRAF V600 mutated malignant melanoma (mM). The non-interventional post-authorisation safety study coveNIS collected real-world data on cobimetinib/vemurafenib treatment focussing on overall survival (OS), safety and utilization. MM patients with brain metastases are usually excluded from clinical studies. coveNIS observed 2 cohorts: mM patients without (Cohort A) and with cerebral metastases (Cohort B), aiming to close the data gap for the latter population. A direct comparison of the 2 cohorts was not intended. The primary effectiveness objective was OS; the safety objective was the incidence of all and of serious adverse events (AEs). Secondary objectives included progression-free survival (PFS), time to development of cerebral metastasis (Cohort A) and time to central nervous system relapse (Cohort B). All statistical analyses were descriptive. Between 2017 and 2021, 95 patients were included (Cohort A: 54, Cohort B: 41 patients) at 32 sites in Germany. Median OS was 21.6 months in Cohort A, 7.4 months in Cohort B. Median PFS was 6.9 months in Cohort A, 5.2 months in Cohort B. The proportion of patients experiencing any AEs was 83.3% (Cohort A) and 87.8% (Cohort B). The two most common AEs in Cohort A were 'diarrhoea' (37%), 'vomiting' (20.4%) and 'pyrexia' (20.4%); in Cohort B 'diarrhoea' (36.6%) and 'fatigue' (22%). In conclusion, the OS rates in Cohort A and Cohort B of coveNIS are in line with the OS data from other trials with BRAF/MEK inhibitors for mM. No new safety signals were observed.

Matched three-dimensional organoids and two-dimensional cell lines of melanoma brain metastases mirror response to targeted molecular therapy

Purpose

Despite significant advances in the treatment paradigm for patients with metastatic melanoma, melanoma brain metastasis (MBM) continues to represent a significant treatment challenge. The study of MBM is limited, in part, by shortcomings in existing preclinical models. Surgically eXplanted Organoids (SXOs) are ex vivo, three-dimensional cultures prepared from primary tissue samples with minimal processing that recapitulate genotypic and phenotypic features of parent tumors and are grown without artificial extracellular scaffolding. We aimed to develop the first matched patient-derived SXO and cell line models of MBM to investigate responses to targeted therapy.

Methods

MBM SXOs were created by a novel protocol incorporating techniques for establishing glioma and cutaneous melanoma organoids. A BRAFV600K-mutant and BRAF-wildtype MBM sample were collected directly from the operating room for downstream experiments. Organoids were cultured in an optimized culture medium without an artificial extracellular scaffold. Concurrently, matched patient-derived cell lines were created. Drug screens were conducted to assess treatment response in SXOs and cell lines.

Results

Organoid growth was observed within 3-4 weeks, and MBM SXOs retained histological features of the parent tissue, including pleomorphic epithelioid cells with abundant cytoplasm, large nuclei, focal melanin accumulation, and strong SOX10 positivity. After sufficient growth, organoids could be manually parcellated to increase the number of replicates. Matched SXOs and cell lines demonstrated sensitivity to BRAF and MEK inhibitors.

Conclusion

Here, we describe the creation of a scaffold-free organoid model of MBM. Further study using SXOs may improve the translational relevance of preclinical studies and enable the study of the metastatic melanoma tumor microenvironment.

A single-center retrospective analysis of prognoses in patients with melanoma brain metastases and effectiveness of treatment in Japan

BACKGROUND

Melanoma brain metastasis (MBM) has a poor prognosis, although recent treatments, including immune checkpoint inhibitors and targeted therapy, have improved the prognosis. However, these systemic therapies have been reported to be less efficient for Asian patients. We investigated the survival of Asian patients with MBM and the effectiveness of systemic therapies.

METHODS

We retrospectively reviewed the survival rates of patients diagnosed with MBM between January 2011 and December 2021 at the National Cancer Center Hospital in Tokyo, Japan. In addition, we identified factors associated with survival using Cox regression analysis.

RESULTS

A total of 135 patients were included. The median overall survival (OS) after an MBM diagnosis was 7.8 months (95% confidence interval [CI] 6.1-9.6). The 6-month and 1-year survival rates were 60.7% and 34.8%, respectively. We identified the prognostic factors of MBM, including non-acral primary location, low serum LDH levels, systemic therapy of single-agent immune checkpoint inhibitors (ICIs) or targeted therapies (TTs), and radiotherapy of stereotactic irradiation (STI). We found no significant difference in effectiveness between single-agent ICIs, the combination of Nivolumab and Ipilimumab (COMBI-ICI), and TTs (COMBI-ICI vs. single-agent ICI, hazard ratio 0.71, 95% confidence interval 0.27-1.88, p = 0.49; COMBI-ICI vs. TT: hazard ratio 0.46, 95% confidence interval 0.14-1.55, p = 0.21).

CONCLUSIONS

Systemic therapy and radiotherapy have improved the survival of MBM patients, but the survival of Asian patients remains poor. Our findings suggest that COMBI-ICIs are not significantly more effective than single-agent ICI or TT in treating MBM.

Diagnostic and Therapeutic Updates in Leptomeningeal Disease

PURPOSE OF REVIEW

Leptomeningeal disease (LMD) is a devastating complication of advanced metastatic cancer associated with a poor prognosis and limited treatment options. This study reviews the current understanding of the clinical presentation, pathogenesis, diagnosis, and treatment of LMD. We highlight opportunities for advances in this disease.

RECENT FINDINGS

In recent years, the use of soluble CSF biomarkers has expanded, suggesting improved sensitivity over traditional cytology, identification of targetable mutations, and potential utility for monitoring disease burden. Recent studies of targeted small molecules and intrathecal based therapies have demonstrated an increase in overall and progression-free survival. In addition, there are several ongoing trials evaluating immunotherapy in LMD. Though overall prognosis of LMD remains poor, studies suggest a potential role for soluble CSF biomarkers in diagnosis and management and demonstrate promising findings in patient outcomes with targeted therapies for specific solid tumors. Despite these advances, there continues to be a gap of knowledge in this disease, emphasizing the importance of inclusion of LMD patients in clinical trials.

Leptomeningeal Metastasis: A Review of the Pathophysiology, Diagnostic Methodology, and Therapeutic Landscape

The present review aimed to establish an understanding of the pathophysiology of leptomeningeal disease as it relates to late-stage development among different cancer types. For our purposes, the focused metastatic malignancies include breast cancer, lung cancer, melanoma, primary central nervous system tumors, and hematologic cancers (lymphoma, leukemia, and multiple myeloma). Of note, our discussion was limited to cancer-specific leptomeningeal metastases secondary to the aforementioned primary cancers. LMD mechanisms secondary to non-cancerous pathologies, such as infection or inflammation of the leptomeningeal layer, were excluded from our scope of review. Furthermore, we intended to characterize general leptomeningeal disease, including the specific anatomical infiltration process/area, CSF dissemination, manifesting clinical symptoms in patients afflicted with the disease, detection mechanisms, imaging modalities, and treatment therapies (both preclinical and clinical). Of these parameters, leptomeningeal disease across different primary cancers shares several features. Pathophysiology regarding the development of CNS involvement within the mentioned cancer subtypes is similar in nature and progression of disease. Consequently, detection of leptomeningeal disease, regardless of cancer type, employs several of the same techniques. Cerebrospinal fluid analysis in combination with varied imaging (CT, MRI, and PET-CT) has been noted in the current literature as the gold standard in the diagnosis of leptomeningeal metastasis. Treatment options for the disease are both varied and currently in development, given the rarity of these cases. Our review details the differences in leptomeningeal disease as they pertain through the lens of several different cancer subtypes in an effort to highlight the current state of targeted therapy, the potential shortcomings in treatment, and the direction of preclinical and clinical treatments in the future. As there is a lack of comprehensive reviews that seek to characterize leptomeningeal metastasis from various solid and hematologic cancers altogether, the authors intended to highlight not only the overlapping mechanisms but also the distinct patterning of disease detection and progression as a means to uniquely treat each metastasis type. The scarcity of LMD cases poses a barrier to more robust evaluations of this pathology. However, as treatments for primary cancers have improved over time, so has the incidence of LMD. The increase in diagnosed cases only represents a small fraction of LMD-afflicted patients. More often than not, LMD is determined upon autopsy. The motivation behind this review stems from the increased capacity to study LMD in spite of scarcity or poor patient prognosis. In vitro analysis of leptomeningeal cancer cells has allowed researchers to approach this disease at the level of cancer subtypes and markers. We ultimately hope to facilitate the clinical translation of LMD research through our discourse.

A Survival Tree of Advanced Melanoma Patients with Brain Metastases Treated with Immune Checkpoint Inhibitors

The efficacy of immune checkpoint inhibitors (ICIs) in patients with advanced melanoma that develop brain metastases (BM) remains unpredictable. In this study, we aimed to identify prognostic factors in patients with melanoma BM who are treated with ICIs. Data from advanced melanoma patients with BM treated with ICIs in any line between 2013 and 2020 were obtained from the Dutch Melanoma Treatment Registry. Patients were included from the time of the treatment of BM with ICIs. Survival tree analysis was performed with clinicopathological parameters as potential classifiers and overall survival (OS) as the response variable. In total, 1278 patients were included. Most patients were treated with ipilimumab-nivolumab combination therapy (45%). The survival tree analysis resulted in 31 subgroups. The median OS ranged from 2.7 months to 35.7 months. The strongest clinical parameter associated with survival in advanced melanoma patients with BM was the serum lactate dehydrogenase (LDH) level. Patients with elevated LDH levels and symptomatic BM had the worst prognosis. The clinicopathological classifiers identified in this study can contribute to optimizing clinical studies and can aid doctors in giving an indication of the patients' survival based on their baseline and disease characteristics.

Neuronal Cannabinoid CB1 Receptors Suppress the Growth of Melanoma Brain Metastases by Inhibiting Glutamatergic Signalling

Melanoma is one of the deadliest forms of cancer. Most melanoma deaths are caused by distant metastases in several organs, especially the brain, the so-called melanoma brain metastases (MBMs). However, the precise mechanisms that sustain the growth of MBMs remain elusive. Recently, the excitatory neurotransmitter glutamate has been proposed as a brain-specific, pro-tumorigenic signal for various types of cancers, but how neuronal glutamate shuttling onto metastases is regulated remains unknown. Here, we show that the cannabinoid CB₁ receptor (CB₁R), a master regulator of glutamate output from nerve terminals, controls MBM proliferation. First, in silico transcriptomic analysis of cancer-genome atlases indicated an aberrant expression of glutamate receptors in human metastatic melanoma samples. Second, in vitro experiments conducted on three different melanoma cell lines showed that the selective blockade of glutamatergic NMDA receptors, but not AMPA or metabotropic receptors, reduces cell proliferation. Third, in vivo grafting of melanoma cells in the brain of mice selectively devoid of CB₁Rs in glutamatergic neurons increased tumour cell proliferation in concert with NMDA receptor activation, whereas melanoma cell growth in other tissue locations was not affected. Taken together, our findings demonstrate an unprecedented regulatory role of neuronal CB₁Rs in the MBM tumour microenvironment.

Efficacy of immunotherapy for melanoma brain metastases in patients with concurrent corticosteroid exposure

Aim: Immune checkpoint inhibitor (ICI) efficacy is undefined for melanoma brain metastases (MBM) with concurrent corticosteroid exposure. Materials & methods: We retrospectively evaluated patients with untreated MBM who received corticosteroids (≥1.5 mg dexamethasone equivalent) within 30 days of ICI. mRECIST criteria and Kaplan-Meier methods defined intracranial progression-free survival (iPFS). The lesion size-response association was evaluated with repeated measures modeling. Results: A total of 109 MBM were evaluated. The patient level intracranial response rate was 41%. Median iPFS was 2.3 months and overall survival was 13.4 months. Larger lesions were more likely to progress, with diameter >2.05 cm most predictive of progression (OR: 18.9; 95% CI: 2.6-139.5; p = 0.004). There was no difference in iPFS with steroid exposure pre- versus post-ICI initiation. Conclusion: In the largest reported ICI+corticosteroid cohort, we identify size dependent MBM response.

Melanoma Brain Metastases: A Retrospective Analysis of Prognostic Factors and Efficacy of Multimodal Therapies

Brain metastasis in cutaneous melanoma (CM) has historically been considered to be a dismal prognostic feature, although recent evidence has highlighted the intracranial activity of combined immunotherapy (IT). Herein, we completed a retrospective study to investigate the impact of clinical-pathological features and multimodal therapies on the overall survival (OS) of CM patients with brain metastases. A total of 105 patients were evaluated. Nearly half of the patients developed neurological symptoms leading to a negative prognosis (p = 0.0374). Both symptomatic and asymptomatic patients benefited from encephalic radiotherapy (eRT) (p = 0.0234 and p = 0.011). Lactate dehydrogenase (LDH) levels two times higher than the upper limit normal (ULN) at the time of brain metastasis onset was associated with poor prognosis (p = 0.0452) and identified those patients who did not benefit from eRT. Additionally, the poor prognostic role of LDH levels was confirmed in patients treated with targeted therapy (TT) (p = 0.0015) concerning those who received immunotherapy (IT) (p = 0.16). Based on these results, LDH levels higher than two times the ULN at the time of the encephalic progression identify those patients with a poor prognosis who did not benefit from eRT. The negative prognostic role of LDH levels on eRT observed in our study will require prospective evaluations.

Impact of Novel Treatments in Patients with Melanoma Brain Metastasis: Real-World Data

BACKGROUND

Melanoma brain metastasis (MBM) is associated with poor outcome, but targeted therapies (TTs) and immune checkpoint inhibitors (ICIs) have revolutionized treatment over the past decade. We assessed the impact of these treatments in a real-world setting.

METHODS

A single-center cohort study was performed at a large, tertiary referral center for melanoma (Erasmus MC, Rotterdam, the Netherlands). Overall survival (OS) was assessed before and after 2015, after which TTs and ICIs were increasingly prescribed.

RESULTS

There were 430 patients with MBM included; 152 pre-2015 and 278 post-2015. Median OS improved from 4.4 to 6.9 months (HR 0.67, p < 0.001) after 2015. TTs and ICIs prior to MBM diagnosis were associated with poorer median OS as compared to no prior systemic treatment (TTs: 2.0 vs. 10.9 and ICIs: 4.2 vs. 7.9 months, p < 0.001). ICIs directly after MBM diagnosis were associated with improved median OS as compared to no direct ICIs (21.5 vs. 4.2 months, p < 0.001). Stereotactic radiotherapy (SRT; HR 0.49, p = 0.013) and ICIs (HR 0.32, p < 0.001) were independently associated with improved OS.

CONCLUSION

After 2015, OS significantly improved for patients with MBM, especially with SRT and ICIs. Demonstrating a large survival benefit, ICIs should be considered first after MBM diagnosis, if clinically feasible.

Brain metastasis screening in the molecular age

The incidence of brain metastases (BM) amongst cancer patients has been increasing due to improvements in therapeutic options and an increase in overall survival. Molecular characterization of tumors has provided insights into the biology and oncogenic drivers of BM and molecular subtype-based screening. Though there are currently some screening and surveillance guidelines for BM, they remain limited. In this comprehensive review, we review and present epidemiological data on BM, their molecular characterization, and current screening guidelines. The molecular subtypes with the highest BM incidence are epithelial growth factor receptor-mutated non-small cell lung cancer (NSCLC), BRCA1, triple-negative (TN), and HER2+ breast cancers, and BRAF-mutated melanoma. Furthermore, BMs are more likely to present asymptomatically at diagnosis in oncogene-addicted NSCLC and BRAF-mutated melanoma. European screening standards recommend more frequent screening for oncogene-addicted NSCLC patients, and clinical trials are investigating screening for BM in hormone receptor+, HER2+, and TN breast cancers. However, more work is needed to determine optimal screening guidelines for other primary cancer molecular subtypes. With the advent of personalized medicine, molecular characterization of tumors has revolutionized the landscape of cancer treatment and prognostication. Incorporating molecular characterization into BM screening guidelines may allow physicians to better identify patients at high risk for BM development and improve patient outcomes.

Changes In Outcomes And Factors Associated With Survival In Melanoma Patients With Brain Metastases

BACKGROUD

Treatment options for patients with melanoma brain metastasis (MBM) have changed significantly in the last decade. Few studies have evaluated changes in outcomes and factors associated with survival in MBM patients over time. The aim of this study is to evaluate changes in clinical features and overall survival (OS) for MBM patients.

METHODS

Patients diagnosed with MBMs from 1/1/2009-12/31/2013 (Prior Era; PE) and 1/1/2014-12/31/2018 (Current Era; CE) at The University of Texas MD Anderson Cancer Center were included in this retrospective analysis. The primary outcome measure was OS. Log-rank test assessed differences between groups; multivariable analyses were performed with Cox proportional hazards models and recursive partitioning analysis (RPA).

RESULTS

791 MBM patients (PE, n=332; CE, n=459) were included in analysis. Median OS from MBM diagnosis was 10.3 months (95% CI, 8.9 - 12.4) and improved in the CE versus PE (14.4 vs. 10.3 months, P < .001). Elevated serum LDH was the only factor associated with worse OS in both PE and CE patients. Factors associated with survival in CE MBM patients included patient age, primary tumor Breslow thickness, prior immunotherapy, leptomeningeal disease (LMD), symptomatic MBMs, and whole brain radiation therapy (WBRT). Several factors associated with OS in the PE were not significant in the CE. RPA demonstrated that elevated serum LDH and prior immunotherapy treatment are the most important determinants of survival in CE MBM patients.

CONCLUSIONS

OS and factors associated with OS have changed for MBM patients. This information can inform contemporary patient management and clinical investigations.

Decoding molecular programs in melanoma brain metastases

Melanoma brain metastases (MBM) variably respond to therapeutic interventions; thus determining patient's prognosis. However, the mechanisms that govern therapy response are poorly understood. Here, we use a multi-OMICS approach and targeted sequencing (TargetSeq) to unravel the programs that potentially control the development of progressive intracranial disease. Molecularly, the expression of E-cadherin (Ecad) or NGFR, the BRAF mutation state and level of immune cell infiltration subdivides tumors into proliferative/pigmented and invasive/stem-like/therapy-resistant irrespective of the intracranial location. The analysis of MAPK inhibitor-naive and refractory MBM reveals switching from Ecad-associated into NGFR-associated programs during progression. NGFR-associated programs control cell migration and proliferation via downstream transcription factors such as SOX4. Moreover, global methylome profiling uncovers 46 differentially methylated regions that discriminate BRAF^mut and wildtype MBM. In summary, we propose that the expression of Ecad and NGFR sub- classifies MBM and suggest that the Ecad-to-NGFR phenotype switch is a rate-limiting process which potentially indicates drug-response and intracranial progression states in melanoma patients.

The Analysis of Trends in Survival for Patients with Melanoma Brain Metastases with Introduction of Novel Therapeutic Options before the Era of Combined Immunotherapy-Multicenter Italian-Polish Report

Stage IV melanoma patients develop melanoma brain metastases (MBM) in 50% of cases. Their prognosis is improving, and its understanding outside the context of clinical trials is relevant. We have retrospectively analyzed the clinical data, course of treatment, and outcomes of 531 subsequent stage IV melanoma patients with BM treated in five reference Italian and Polish melanoma centers between 2014 and 2021. Patients with MBM after 2017 had a better prognosis, with a significantly improved median of overall survival (OS) after 2017 in the worst mol-GPA prognostic groups (mol-GPA ≤ 2): a median OS >6 months and HR 0.76 vs. those treated before 2017 (CI: 0.60−0.97, p = 0.027). In our prognostic model, mol-GPA was highly predictive for survival, and symptoms without steroid use did not have prognostic significance. Local therapy significantly improved survival regardless of the year of diagnosis (treated before or after 2017), with median survival >12 months. Systemic therapy improved outcomes when it was combined with local therapy. Local surgery was associated with improved OS regardless of the timing related to treatment start (i.e., before or after 30 days from MBM diagnosis). Local and systemic treatment significantly prolong survival for the poorest mol-GPA prognosis. Use of modern treatment modalities is justified in all mol-GPA prognostic groups.

Melanoma central nervous system metastases: An update to approaches, challenges, and opportunities

Brain metastases are the most common brain malignancy. This review discusses the studies presented at the third annual meeting of the Melanoma Research Foundation in the context of other recent reports on the biology and treatment of melanoma brain metastases (MBM). Although symptomatic MBM patients were historically excluded from immunotherapy trials, efforts from clinicians and patient advocates have resulted in more inclusive and even dedicated clinical trials for MBM patients. The results of checkpoint inhibitor trials were discussed in conversation with current standards of care for MBM patients, including steroids, radiotherapy, and targeted therapy. Advances in the basic scientific understanding of MBM, including the role of astrocytes and metabolic adaptations to the brain microenvironment, are exposing new vulnerabilities which could be exploited for therapeutic purposes. Technical advances including single-cell omics and multiplex imaging are expanding our understanding of the MBM ecosystem and its response to therapy. This unprecedented level of spatial and temporal resolution is expected to dramatically advance the field in the coming years and render novel treatment approaches that might improve MBM patient outcomes.

Longest survival with primary intracranial malignant melanoma: A case report and literature review

BACKGROUND

Primary intracranial malignant melanoma (PIMM) is rare, and its prognosis is very poor. It is not clear what systematic treatment strategy can achieve long-term survival. This case study attempted to identify the optimal strategy for long-term survival outcomes by reviewing the PIMM patient with the longest survival following comprehensive treatment and by reviewing the related literature.

CASE SUMMARY

The patient is a 47-year-old Chinese man who suffered from dizziness and gait disturbance. He underwent surgery for right cerebellum melanoma and was subsequently diagnosed by pathology in June 2000. After the surgery, the patient received three cycles of chemotherapy but relapsed locally within 4 mo. Following the second surgery for total tumor resection, the patient received an injection of Newcastle disease virus-modified tumor vaccine, interferon, and β-elemene treatment. The patient was tumor-free with a normal life for 21 years before the onset of the recurrence of melanoma without any symptoms in July 2021. A third gross-total resection with adjuvant radiotherapy and temozolomide therapy was performed. Brain magnetic resonance imaging showed no residual tumor or recurrence 3 mo after the 3^rd operation, and the patient recovered well without neurological dysfunction until the last follow-up in June 2022, which was 22 years following the initial treatment.

CONCLUSION

It is important for patients with PIMM to receive comprehensive treatment to enable the application of the most appropriate treatment strategies. Long-term survival is not impossible in patients with these malignancies.

Molecular Mechanisms Driving the Formation of Brain Metastases

Simple Summary

Brain metastases are the most common brain tumor in adults and are associated with poor prognosis. The propensity of different solid tumors to metastasize varies greatly, with lung, breast, and melanoma primary tumors commonly leading to brain metastases, while other primaries such as prostate rarely metastasize to the brain. The molecular mechanisms that predispose and facilitate brain metastasis development are poorly understood. In this review, we present the current data on the genomic landscape of brain metastases that arise from various primary cancers and also outline potential molecular mechanisms that drive the formation of distant metastases in the brain.

Abstract

Targeted therapies for cancers have improved primary tumor response rates, but concomitantly, brain metastases (BM) have become the most common brain tumors in adults and are associated with a dismal prognosis of generally less than 6 months, irrespective of the primary cancer type. They most commonly occur in patients with primary breast, lung, or melanoma histologies; however, they also appear in patients with other primary cancers including, but not limited to, prostate cancer, colorectal cancer, and renal cell carcinoma. Historically, molecular biomarkers have normally been identified from primary tumor resections. However, clinically informative genomic alterations can occur during BM development and these potentially actionable alterations are not always detected in the primary tumor leading to missed opportunities for effective targeted therapy. The molecular mechanisms that facilitate and drive metastasis to the brain are poorly understood. Identifying the differences between the brain and other extracranial sties of metastasis, and between primary tumors and BM, is essential to improving our understanding of BM development and ultimately patient management and survival. In this review, we present the current data on the genomic landscape of BM from various primary cancers which metastasize to the brain and outline potential mechanisms which may play a role in promoting the formation of the distant metastases in the brain.

A Conceptual Framework for Inducing T Cell-Mediated Immunity Against Glioblastoma

Glioblastoma is a highly aggressive brain tumor with limited treatment options. Several major challenges have limited the development of novel therapeutics, including the extensive heterogeneity of tumor cell states within each glioblastoma and the ability of glioma cells to diffusely infiltrate into neighboring healthy brain tissue, including the contralateral hemisphere. A T cell-mediated immune response could deal with these challenges based on the ability of polyclonal T cell populations to recognize diverse tumor antigens and perform surveillance throughout tissues. Here we will discuss the major pathways that inhibit T cell-mediated immunity against glioblastoma, with an emphasis on receptor-ligand systems by which glioma cells and recruited myeloid cells inhibit T cell function. A related challenge is that glioblastomas tend to be poorly infiltrated by T cells, which is not only caused by inhibitory molecular pathways but also currently utilized drugs, in particular high-dose corticosteroids that kill activated, proliferating T cells. We will discuss innovative approaches to induce glioblastoma-directed T cell responses, including neoantigen-based vaccines and sophisticated CAR T cell approaches that can target heterogeneous glioblastoma cell populations. Finally, we will propose a conceptual framework for the future development of T cell-based immunotherapies for glioblastoma.

Activity and resistance of a brain-permeable paradox breaker BRAF inhibitor in melanoma brain metastasis

The therapeutic benefit of approved BRAF and MEK inhibitors (BRAFi/MEKi) in patients with brain metastatic BRAF V600E/K-mutated melanoma is limited and transient. Resistance largely occurs through the restoration of MAPK signaling via paradoxical BRAF activation, highlighting the need for more effective therapeutic options. Aiming to address this clinical challenge, we characterized the activity of a potent, brain-penetrant paradox breaker BRAFi (compound 1a, C1a) as first line therapy and following progression upon treatment with approved BRAFi and BRAFi/MEKi therapies. C1a activity was evaluated in vitro and in vivo in melanoma cell lines and patient-derived models of BRAF V600E-mutant melanoma brain metastases following relapse after treatment with BRAFi/MEKi. C1a showed superior efficacy compared to approved BRAFi, both in subcutaneous and brain metastatic models. Importantly, C1a manifested potent and prolonged antitumor activity even in models that progressed on BRAFi/MEKi treatment. Analysis of mechanisms of resistance to C1a revealed MAPK reactivation under drug treatment as the predominant resistance-driving event in both subcutaneous and intracranial tumors. Specifically, BRAF kinase domain duplication was identified as a frequently occurring driver of resistance to C1a. Combination therapies of C1a and anti-PD1 antibody proved to significantly reduce disease recurrence. Collectively, these preclinical studies validate the outstanding antitumor activity of C1a in brain metastasis, support clinical investigation of this agent in patients pretreated with BRAFi/MEKi, unveil genetic drivers of tumor escape from C1a, and identify a combinatorial treatment that achieves long-lasting responses.

Brain metastases: An update on the multi-disciplinary approach of clinical management

IMPORTANCE

Brain metastasis (BM) is the most common malignant intracranial neoplasm in adults with over 100,000 new cases annually in the United States and outnumbering primary brain tumors 10:1.

OBSERVATIONS

The incidence of BM in adult cancer patients ranges from 10-40%, and is increasing with improved surveillance, effective systemic therapy, and an aging population. The overall prognosis of cancer patients is largely dependent on the presence or absence of brain metastasis, and therefore, a timely and accurate diagnosis is crucial for improving long-term outcomes, especially in the current era of significantly improved systemic therapy for many common cancers. BM should be suspected in any cancer patient who develops new neurological deficits or behavioral abnormalities. Gadolinium enhanced MRI is the preferred imaging technique and BM must be distinguished from other pathologies. Large, symptomatic lesion(s) in patients with good functional status are best treated with surgery and stereotactic radiosurgery (SRS). Due to neurocognitive side effects and improved overall survival of cancer patients, whole brain radiotherapy (WBRT) is reserved as salvage therapy for patients with multiple lesions or as palliation. Newer approaches including multi-lesion stereotactic surgery, targeted therapy, and immunotherapy are also being investigated to improve outcomes while preserving quality of life.

CONCLUSION

With the significant advancements in the systemic treatment for cancer patients, addressing BM effectively is critical for overall survival. In addition to patient's performance status, therapeutic approach should be based on the type of primary tumor and associated molecular profile as well as the size, number, and location of metastatic lesion(s).

Multimodality durable salvage of recurrent brain metastases refractory to LITT, SRS and immunotherapy with resection and cesium-131 brachytherapy: case report and literature review

Brain metastases (BrM) are treated with multimodality therapy, however the optimal combination and timing of modalities in the setting of recurrent tumours that have failed prior treatments remain poorly defined. We present a case of a patient with biopsy-confirmed renal cell carcinoma BrM with good performance status initially treated with laser interstitial thermal ablation therapy (LITT) followed by stereotactic radiosurgery and dual checkpoint inhibitor immunotherapy. He subsequently developed rapid in-field recurrence which was treated with salvage surgical resection and implantation of intracavitary cesium-131 brachytherapy. The patient's disease remained stable through 18 months postoperatively. This case illustrates the range of options available and provides a combination salvage therapy strategy in a select group of locally recurrent patients who have exhausted conventional treatment options.

Salvage resection of recurrent previously irradiated brain metastases: tumor control and radiation necrosis dependency on adjuvant re-irradiation

PURPOSE

The efficacy of salvage resection (SR) of recurrent brain metastases (rBrM) following stereotactic radiosurgery (SRS) is undefined. We sought to describe local recurrence (LR) and radiation necrosis (RN) rates in patients undergoing SR, with or without adjuvant post-salvage radiation therapy (PSRT).

METHODS

A retrospective cohort study evaluated patients undergoing SR of post-SRS rBrM between 3/2003-2/2020 at an NCI-designated cancer center. Cases with histologically-viable malignancy were stratified by receipt of adjuvant PSRT within 60 days of SR. Clinical outcomes were described using cumulative incidences in the clustered competing-risks setting, competing risks regression, and Kaplan-Meier methodology.

RESULTS

One-hundred fifty-five rBrM in 135 patients were evaluated. The overall rate of LR was 40.2% (95% CI 34.3-47.2%) at 12 months. Thirty-nine (25.2%) rBrM treated with SR + PSRT trended towards lower 12-month LR versus SR alone [28.8% (95% CI 17.0-48.8%) versus 43.9% (95% CI 36.2-53.4%), p = .07 by multivariate analysis]. SR as re-operation (p = .03) and subtotal resection (p = .01) were independently associated with higher rates of LR. On univariate analysis, tumor size (p = .48), primary malignancy (p = .35), and PSRT technique (p = .43) bore no influence on LR. SR + PSRT was associated with an increased risk of radiographic RN at 12 months versus SR alone [13.4% (95% CI 5.5-32.7%) versus 3.5% (95% CI 1.5-8.0%), p = .02], though the percentage with symptomatic RN remained low (5.1% versus 0.9%, respectively). Median overall survival from SR was 13.4 months (95% CI 10.5-17.7).

CONCLUSION

In this largest-known series evaluating SR outcomes in histopathologically-confirmed rBrM, we identify a significant LR risk that may be reduced with adjuvant PSRT and with minimal symptomatic RN. Prospective analysis is warranted.

Salvage Surgery for Local Control of Brain Metastases After Previous Stereotactic Radiosurgery: A Single-Center Series

BACKGROUND

Although overall survival (OS) has improved in patients with brain metastases (BMs), control of recurrent BMs remains a therapeutic challenge. Salvage surgery may achieve acceptable control rates in the setting of progression after previous stereotactic radiosurgery (SRS), yet it remains a question how additional adjuvant therapies may affect outcomes and how patient selection for salvage surgery may be optimized.

METHODS

Patients receiving salvage surgery for BM progression after previous SRS were retrospectively reviewed from a single center. Outcomes of interest included local tumor progression, leptomeningeal dissemination, and OS. Cox proportional hazard models and nominal logistic regression were applied to determine factors associated with outcomes of interest.

RESULTS

A total of 43 patients with 50 BMs were included. After salvage surgery, local progression was observed for 17 BMs (34%), leptomeningeal dissemination was observed in 17 patients (39.5%), and censored median OS was 17.9 months. On multivariate analysis, use of brachytherapy was associated with improved local control (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04-0.6; P = 0.008). For patients treated with SRS ≥4.5 months before salvage surgery, both brachytherapy (HR, 0.07; 95% CI, 0.01-0.39; P = 0.002) and postoperative adjuvant SRS (HR, 0.14; 95% CI, 0.02-1.00; P = 0.05) were associated with improved local control compared with no adjuvant radiation therapy. Presence of extracranial malignancy (HR, 6.70; 95% CI, 2.58-17.42; P < 0.0001) was associated with shorter survival. Graded prognostic assessment underestimated survival in 79.1% of patients, with a mean difference of 18.9 months between graded prognostic assessment-estimated and actual OS.

CONCLUSIONS

In properly selected patients, salvage surgery may be an appropriate therapy for BM progression after previous SRS. Adjuvant brachytherapy and repeat SRS can offer significant benefit for local control with salvage resection.

Outcomes Following Hypofractionated Stereotactic Radiotherapy to the Cavity After Surgery for Melanoma Brain Metastases

AIMS

Hypofractionated stereotactic radiotherapy (HSRT) to the cavity after surgical resection of brain metastases improves local control. Most reported cohorts include few patients with melanoma, a population known to have high rates of recurrence and neurological death. We aimed to assess outcomes in patients with melanoma brain metastases who received HSRT after surgery at two Australian institutions.

MATERIALS AND METHODS

A retrospective analysis was carried out including patients treated between January 2012 and May 2020. HSRT was recommended for patients with melanoma brain metastases at high risk of local recurrence after surgery. Treatment was delivered using appropriately commissioned linear accelerators. Routine follow-up included surveillance magnetic resonance imaging brain every 3 months for at least 2 years. Primary outcomes were overall survival, local control, incidence of radiological radionecrosis and symptomatic radionecrosis.

RESULTS

There were 63 cavities identified in 57 patients. The most common HSRT dose prescriptions were 24 Gy in three fractions and 27.5 Gy in five fractions. The median follow-up was 32 months in survivors. Local control was 90% at 1 year, 83% at 2 years and 76% at 3 years. Subtotal brain metastases resection (hazard ratio 12.5; 95% confidence interval 1.4-111; P = 0.0238) was associated with more local recurrence. Overall survival was 64% at 1 year, 45% at 2 years and 40% at 3 years. There were 10 radiological radionecrosis events (16% of cavities) during the study period, with 5% at 1 year and 8% at 2 years after HSRT. The median time to onset of radiological radionecrosis was 21 months (range 6-56). Of these events, three became symptomatic (5%) during the study period at a median time to onset of 26 months (range 21-32).

CONCLUSION

Cavity HSRT is associated with high rates of local control in patients with melanoma brain metastases. Subtotal resection strongly predicts for local recurrence after HSRT. Symptomatic radionecrosis occurred in 5% of cavities but increased to 8% of longer-term survivors.

Risk of tract recurrence with stereotactic biopsy of brain metastases: an 18-year cancer center experience

OBJECTIVE

Stereotactic biopsy is increasingly performed on brain metastases (BrMs) as improving cancer outcomes drive aggressive multimodality treatment, including laser interstitial thermal therapy (LITT). However, the tract recurrence (TR) risk is poorly defined in an era defined by focused-irradiation paradigms. As such, the authors aimed to define indications and adjuvant therapies for this procedure and evaluate the BrM-biopsy TR rate.

METHODS

In a single-center retrospective review, the authors identified stereotactic BrM biopsies performed from 2002 to 2020. Surgical indications, radiographic characteristics, stereotactic planning, dosimetry, pre- and postoperative CNS-directed and systemic treatments, and clinical courses were collected. Recurrence was evaluated using RANO-BM (Response Assessment in Neuro-Oncology Brain Metastases) criteria.

RESULTS

In total, 499 patients underwent stereotactic intracranial biopsy for any diagnosis, of whom 25 patients (5.0%) underwent biopsy for pathologically confirmed viable BrM, a proportion that increased over the time period studied. Twelve of the 25 BrM patients had ≥ 3 months of radiographic follow-up, of whom 6 patients (50%) developed new metastatic growth along the tract at a median of 5.0 months post-biopsy (range 2.3-17.1 months). All of the TR cases had undergone pre- or early post-biopsy stereotactic radiosurgery (SRS), and 3 had also undergone LITT at the time of initial biopsy. TRs were treated with resection, reirradiation, or observation/systemic therapy.

CONCLUSIONS

In this study the authors identified a nontrivial, higher than previously described rate of BrM-biopsy tract recurrence, which often required additional surgery or radiation and justified close radiographic surveillance. As BrMs are commonly treated with SRS limited to enhancing tumor margins, consideration should be made, in cases lacking CNS-active systemic treatments, to include biopsy tracts in adjuvant radiation plans where feasible.

Epidemiology of brain metastases and leptomeningeal disease

Brain metastases affect a significant percentage of patients with advanced extracranial malignancies. Yet, the incidence of brain metastases remains poorly described, largely due to limitations of population-based registries, a lack of mandated reporting of brain metastases to federal agencies, and historical difficulties with delineation of metastatic involvement of individual organs using claims data. However, in 2016, the Surveillance Epidemiology and End Results (SEER) program released data relating to the presence vs absence of brain metastases at diagnosis of oncologic disease. In 2020, studies demonstrating the viability of utilizing claims data for identifying the presence of brain metastases, date of diagnosis of intracranial involvement, and initial treatment approach for brain metastases were published, facilitating epidemiologic investigations of brain metastases on a population-based level. Accordingly, in this review, we discuss the incidence, clinical presentation, prognosis, and management patterns of patients with brain metastases. Leptomeningeal disease is also discussed. Considerations regarding individual tumor types that commonly metastasize to the brain are provided.

Cerebrospinal fluid diversion for leptomeningeal metastasis: palliative, procedural and oncologic outcomes

BACKGROUND

Leptomeningeal metastasis (LM) occurs in 3-5% of patients with solid metastatic tumors and often portends a severe prognosis including symptomatic hydrocephalus and intracranial hypertension. Cerebrospinal fluid (CSF) shunting can provide symptomatic relief in this patient subset; however, few studies have examined the role of shunting in the palliation, prognosis and overall oncologic care of these patients.

OBJECTIVE

To identify and evaluate risk factors associated with prognosis after CSF diversion and assess surgical, symptomatic and oncologic outcomes in this population.

METHODS

A retrospective study was conducted on patients with solid-malignancy LM treated with a shunt at a NCI-designated Comprehensive Cancer Center between 2010 and 2019.

RESULTS

One hundred and ninety patients with metastatic LM underwent CSF diversion. Overall survival was 4.14 months from LM diagnosis (95% CI: 3.29-4.70) and 2.43 months (95% CI: 2.01-3.09) from shunting. Karnofsky performance status (KPS) at time of shunting and brain metastases (BrM) number at LM diagnosis demonstrated significant associations with survival (HR = 0.66; 95% CI [0.51-0.86], p = 0.002; HR = 1.40; 95% CI [1.01-1.93] per 10 BrM, p = 0.04, respectively). Eighty-three percent of patients experienced symptomatic relief, and 79% were discharged home or to rehabilitation facilities post-shunting. Post-shunt, 56% of patients received additional systemic therapy or started or completed WBRT. Complications included infection (5%), symptomatic subdural hygroma/hematoma (6.3%), and shunt externalization/removal/repair (8%). Abdominal seeding was not identified.

CONCLUSIONS

CSF diversion for LM with hydrocephalus and intracranial hypertension secondary to metastasis can achieve symptomatic relief, hospital discharge, and return to further oncologic therapy, with a complication profile unique to this pathophysiology. However, decision-making in this population must incorporate end-of-life goals of care given limited prognosis.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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