Surgical management of melanoma brain metastases in patients treated with immunotherapy

Systemic Therapy for Melanoma Brain and Leptomeningeal Metastases

OPINION STATEMENT

Melanoma has a high propensity to metastasize to the brain which portends a poorer prognosis. With advanced radiation techniques and targeted therapies, outcomes however are improving. Melanoma brain metastases are best managed in a multi-disciplinary approach, including medical oncologists, neuro-oncologists, radiation oncologists, and neurosurgeons. The sequence of therapies is dependent on the number and size of brain metastases, status of systemic disease control, prior therapies, performance status, and neurological symptoms. The goal of treatment is to minimize neurologic morbidity and prolong both progression free and overall survival while maximizing quality of life. Surgery should be considered for solitary metastases, or large and/or symptomatic metastases with edema. Stereotactic radiosurgery offers a benefit over whole-brain radiation attributed to the relative radioresistance of melanoma and reduction in neurotoxicity. Thus far, data supports a more durable response with systemic therapy using combination immunotherapy of ipilimumab and nivolumab, though targeting the presence of BRAF mutations can also be utilized. BRAF inhibitor therapy is often used after immunotherapy failure, unless a more rapid initial response is needed and then can be done prior to initiating immunotherapy. Further trials are needed, particularly for leptomeningeal metastases which currently require the multi-disciplinary approach to determine best treatment plan.

Comparison of immunotherapy combined with stereotactic radiotherapy and targeted therapy for patients with brain metastases: A systemic review and meta-analysis

Advances in brain imaging have led to a higher incidence of brain metastases (BM) being diagnosed. Stereotactic radiotherapy (SRS), systemic immunotherapy, and targeted drug therapy are commonly used for treating BM. In this study, we summarized the differences in overall survival (OS) between several treatments alone and in combination. We carried out a systematic literature search on Pubmed, EMBASE, and Cochrane Library. Differences in OS associated with Immune checkpoint inhibitors (ICI) alone versus targeted therapy alone and SRS + ICI or ICI alone were evaluated. This analysis was conducted on 11 studies involving 4,154 patients. The comprehensive results of fixed effect model showed that the OS of SRS + ICI group was longer than that of the ICI group (hazard ratio, 1.72; 95% CI: 1.41-2.11; P = 0.22; I ² = 30%). The combined fixed-effect model showed that the OS time of ICI was longer than that of targeted therapy (hazard ratio, 2.09; 95% CI: 1.37-3.20; P = 0.21; I ² = 35%). The study had a low risk of bias. In conclusion, our analysis confirmed that immunotherapy alone showed a higher OS benefit in BM patients than targeted therapy alone. The total survival time of patients with SRS combined with ICI was higher than that of patients with single ICI.

Real-world data on melanoma brain metastases and survival outcome

Novel medical therapies have revolutionized outcome for patients with melanoma. However, patients with melanoma brain metastases (MBM) still have poor survival. Data are limited as these patients are generally excluded from clinical trials, wherefore real-world data on clinical outcome may support evidence-based treatment choices for patients with MBM. Patients diagnosed with MBM between 2008 and 2020 were included retrospectively. Patient characteristics, treatment, and outcome data were recorded from The Danish Metastatic Melanoma Database, pathology registries, electronic patient files, and radiation plans. Anti-programmed cell death protein 1 antibodies and the combination of BRAF/MEK-inhibitors were introduced in Denmark in 2015, and the cohort was split accordingly for comparison. A total of 527 patients were identified; 148 underwent surgical excision of MBM, 167 had stereotactic radiosurgery (SRS), 270 received whole-brain radiation therapy (WBRT), and 343 received systemic therapies. Median overall survival (mOS) for patients diagnosed with MBM before and after 2015 was 4.4 and 7.6 months, respectively. Patients receiving surgical excision as first choice of treatment had the best mOS of 10.9 months, whereas patients receiving WBRT had the worst outcome (mOS, 3.4 months). Postoperative SRS did not improve survival or local control after surgical excision of brain metastases. Of the 40 patients alive >3 years after diagnosis of MBM, 80% received immunotherapy at some point after diagnosis. Patients with meningeal carcinosis did not benefit from treatment with CPI. Outcome for patients with MBM has significantly improved after 2015, but long-term survivors are rare. Most patients alive >3 years after diagnosis of MBM received immunotherapy.

Current Treatment Approaches and Global Consensus Guidelines for Brain Metastases in Melanoma

Background

Up to 60% of melanoma patients develop melanoma brain metastases (MBM), which traditionally have a poor diagnosis. Current treatment strategies include immunotherapies (IO), targeted therapies (TT), and stereotactic radiosurgery (SRS), but there is considerable heterogeneity across worldwide consensus guidelines.

Objective

To summarize current treatments and compare worldwide guidelines for the treatment of MBM.

Methods

Review of global consensus treatment guidelines for MBM patients.

Results

Substantial evidence supported that concurrent IO or TT plus SRS improves progression-free survival (PFS) and overall survival (OS). Guidelines are inconsistent with regards to recommendations for surgical resection of MBM, since surgical resection of symptomatic lesions alleviates neurological symptoms but does not improve OS. Whole-brain radiation therapy is not recommended by all guidelines due to negative effects on neurocognition but can be offered in rare palliative scenarios.

Conclusion

Worldwide consensus guidelines consistently recommend up-front combination IO or TT with or without SRS for the treatment of MBM.

Tumor-promoting properties of karyopherin β1 in melanoma by stabilizing Ras-GTPase-activating protein SH3 domain-binding protein 1

The nuclear import receptor karyopherin β1 (KPNB1), a member of the Karyopherin protein family, is reported to be overexpressed in various cancers and promote carcinogenesis. By analyzing the correlation between the expression of KPNB1 and the overall survival rate of melanoma patients, we found that melanoma patients with higher expression of KPNB1 had worse survival. Furthermore, the database analyzed that the KPNB1 mRNA level was higher in melanoma samples than that in skin nevus tissues. We thus proposed that KPNB1 played a role in promoting melanoma development, and conducted gain-of- and loss-of-function experiments to test our hypothesis. We found that KPNB1 knockdown significantly retarded the growth and metastasis of melanoma cells in vitro and in vivo, and increased their sensitivity towards the anti-tumor drug cisplatin. KPNB1 overexpression had opposite effects. Notably, in melanoma cells, KPNB1 overexpression significantly decreased Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) protein level, which was also overexpressed in melanoma samples and enhanced malignant behaviors of melanoma cells. We further demonstrated that KPNB1 overexpression induced deubiquitination of G3BP1, and prevented its degradation. However, KPNB1 overexpression hardly affected the nuclear translocation of G3BP1. Additionally, alterations induced by KPNB1 overexpression were partly reversed by G3BP1 inhibition. Therefore, the results suggest that KPNB1 may promote melanoma progression by stabilizing the G3BP1 protein. KPNB1-G3BP1 axis represents a potential therapeutic targetable node for melanoma.

Immune response pathways enriched in breast cancer samples with brain metastasis

BACKGROUND

Breast cancer (BC) is the most common form of cancer in women. BC brain metastasis (BM) is associated with poor prognosis, especially for Triple negative breast cancer (TNBC). However, the driver genes of this clinical characteristic are poorly understood.

METHODS

This study conducted a transcriptome-wide analysis of gene expression levels in BCBM samples from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) datasets. Clinical data and gene expression matrix of TNBC samples were collected. Differential analysis and functional enrichment of metastasis vs. non metastasis data samples were conducted. Genes associated with overall survival and BM event was scanned.

RESULTS

Up-regulation in 120 genes and down-regulation in 56 genes were found in TNBC metastasis data. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) clustering using expression alternated genes showed unique immune-gene enrichment in BM samples. Immune response category GO:000695 was found as the most significant term associated with metastasis event. KEGG pathways including cytokine pathways and Primary immunodeficiency were significantly changed in metastasis samples. ESR1 and FYB2 genes expression changes were found to be linked to survival or BM events.

CONCLUSIONS

Our results suggest that data-mining on the immune microenvironment of BM might be useful in future study.

Oncolytic Virotherapy for Melanoma Brain Metastases, a Potential New Treatment Paradigm?

INTRODUCTION

Melanoma brain metastases remain a devastating disease process with poor prognosis. Recently, there has been a surge in studies demonstrating the efficacy of oncolytic virotherapy for brain tumor treatment. Given their specificity and amenability to genetic modification, the authors explore the possible role of oncolytic virotherapy as a potential treatment option for patients with melanoma brain metastases.

METHODS

A comprehensive literature review including both preclinical and clinical evidence of oncolytic virotherapy for the treatment of melanoma brain metastasis was performed.

RESULTS

Oncolytic virotherapy, specifically T-VEC (Imlygic™), was approved for the treatment of melanoma in 2015. Recent clinical trials demonstrate promising anti-tumor changes in patients who have received T-VEC; however, there is little evidence for its use in metastatic brain disease based on the existing literature. To date, only two single cases utilizing virotherapy in patients with metastatic brain melanoma have been reported, specifically in patients with treatment refractory disease. Currently, there is not sufficient data to support the use of T-VEC or other viruses for intracranial metastatic melanoma. In developing a virotherapy treatment paradigm for melanoma brain metastases, several factors must be considered, including route of administration, need to bypass the blood-brain barrier, viral tumor infectivity, and risk of adverse events.

CONCLUSIONS

Evidence for oncolytic virotherapy treatment of melanoma is limited primarily to T-VEC, with a noticeable paucity of data in the literature with respect to brain tumor metastasis. Given the promising findings of virotherapy for other brain tumor types, oncolytic virotherapy has great potential to offer benefits to patients afflicted with melanoma brain metastases and warrants further investigation.

Three-dimensional in vitro tissue culture models of brain organoids

Brain organoids are three-dimensional self-assembled structures that are derived from human induced pluripotent stem cells (hiPSCs). They can recapitulate the spatiotemporal organization and function of the brain, presenting a robust system for in vitro modeling of brain development, evolution, and diseases. Significant advances in biomaterials, microscale technologies, gene editing technologies, and stem cell biology have enabled the construction of human specific brain structures in vitro. However, the limitations of long-term culture, necrosis, and hypoxic cores in different culture models obstruct brain organoid growth and survival. The in vitro models should facilitate oxygen and nutrient absorption, which is essential to generate complex organoids and provides a biomimetic microenvironment for modeling human brain organogenesis and human diseases. This review aims to highlight the progress in the culture devices of brain organoids, including dish, bioreactor, and organ-on-a-chip models. With the modulation of bioactive molecules and biomaterials, the generated organoids recapitulate the key features of the human brain in a more reproducible and hyperoxic fashion. Furthermore, an outlook for future preclinical studies and the genetic modifications of brain organoids is presented.

Local failure after stereotactic radiosurgery (SRS) for intracranial metastasis: analysis from a cooperative, prospective national registry

INTRODUCTION

Stereotactic radiosurgery (SRS) has been increasingly employed to treat patients with intracranial metastasis, both as a salvage treatment after failed whole brain radiation therapy (WBRT) and as an initial treatment. "Several studies have shown that SRS may be as effective as WBRT with the added benefit of preserving neuro-cognition". However, some patients may have local failure following SRS for intracranial metastasis, defined as increase in total lesion volume by 25% after at least 3 months of follow up.

METHODS

The SRS registry, established by the Neuro point alliance (NPA) under the auspices of the American Association of Neurological Surgeons (AANS), was queried for patients with intracranial metastasis receiving SRS at the participating sites. Demographic, clinical symptoms, tumor, and treatment characteristics as well as follow up status were summarized for the cohort. A multivariable explanatory cox- regression was performed to evaluate the impact of each of the factors on time to local failure.at last follow-up.

RESULTS

A total of 441 patients with 1255 intracranial metastatic lesions undergoing SRS were identified. The most common primary cancer histology was non-small cell lung cancer (43.8%, n = 193). More than half of the cohort had more than 1 metastatic lesion (2-3 lesions: 29.5%, n = 130; more than 3 lesions: 25.2% (n = 111). The average duration of follow-up for the cohort was found to be 8.4 months (SD = 7.61). The mean clinical treatment volume (CTV), after adding together the volume of each lesion for each patient was 5.39 cc (SD = 7.6) at baseline. A total of 20.2% (n = 89) had local failure (increase in volume by  > 25%) with a mean time to progression of 7.719 months (SD = 6.09). The progression free survival (PFS) for the cohort at 3, 6 and 12 months were found to be 94.9%, 84.3%, and 69.4%, respectively. On multivariable cox regression analysis, factors associated with increased hazard of local failure included male gender (HR 1.65, 95% CI 1.03-2.66, p = 0.037), chemotherapy at or before SRS (HR = 2.39, 95% CI 1.41-4.05, p = 0.001), WBRT at or before SRS (HR = 2.21, 95% CI 1.16- 4.22, p = 0.017), while surgical resection (HR 0.45, 95% CI 0.21-0. 97, p = 0.04) and immunotherapy (0.34, 95% CI 0.16-0.50, p = 0.014) were associated with lower hazard of local failure.

CONCLUSION

Factors found to be predictive of local failure included higher RPA score and those receiving chemotherapy, while patients undergoing surgical resection and those with occipital lobe lesions were less likely to experience local failure. Our analyses not only corroborate those previously reported but also demonstrate the utility of a multi-institutional registry to advance real-world SRS research for patients with intracranial metastatic lesions.

Management of melanoma brain metastases: Evidence-based clinical practice guidelines by Cancer Council Australia

INTRODUCTION

The brain is a common site of metastatic disease for patients with advanced melanoma. Brain metastasis portends a poor prognosis, often causing deterioration in neurological function and quality of life, and leading to neurological death. Treatment approaches including surgery, radiotherapy and systemic therapy can lead to better control of this problem. Therefore, appropriate guidelines for the management of melanoma brain metastases need to be established, with regular updating when new treatment options become available.

METHODS

A multidisciplinary working party established by Cancer Council Australia has produced up-to-date, evidence-based clinical practice guidelines for the management of melanoma. After selecting key clinical questions, a comprehensive literature search for relevant studies was conducted, followed by systematic review of those studies. Data were summarised and the evidence was assessed, leading to the development of recommendations.

MAIN RECOMMENDATIONS

Symptomatic lesions are best treated with surgery, when possible; this provides safe and effective local control. For patients with single or a small number of asymptomatic brain metastases, stereotactic radiotherapy is recommended, but in asymptomatic patients who have not previously received systemic treatment, drug therapy can be considered as a first-line treatment option. Whole brain radiotherapy may provide palliative benefits in patients with multiple brain metastases. Whenever possible, melanoma patients with brain metastases should be managed by a multidisciplinary team of melanoma specialists that considers the optimal combination and sequencing of surgery, radiotherapy and systemic therapy.

Survival in melanoma brain metastases in the era of novel systemic therapies

Background

Melanoma brain metastases (MBMs) have historically poor overall survival (OS). Recently introduced systemic anticancer therapies (SACTs), namely targeted therapies such as BRAF inhibitors and immunotherapy, to control advanced disease have shown improved survival. Today, increasingly aggressive strategies are sought for MBM. We review outcomes in MBM after surgery or stereotactic radiosurgery (SRS) and the survival impact in advanced systemic disease when combined with novel anticancer therapies.

Methods

A retrospective cohort study of patients referred to a regional neuro-oncology multidisciplinary team (MDT) meeting with MBM. Demographic data, extent of systemic disease, and data on surgical and oncological management were collected, plus the use of SACT. The primary outcomes were median OS, 12- and 24-month survival, and progression-free survival.

Results

Between 2010 and 2018, 142 patients with MBM were referred. Following the introduction of SACT, the rate of referrals to MDT more than doubled from 11.6 to 25.7 patients per year. Focal brain metastasis was treated surgically in 23 (16.2%) patients and by SRS in 29 (20.4%). Fifty-six (39.4%) patients underwent palliative whole-brain radiotherapy and 34 (23.9%) did not receive treatment. Median OS was 11 months for the surgical cohort, 9 months for the SRS cohort, and increased when treatment with or without SACT was considered to 23 and 12 months, respectively.

Conclusion

In the setting of SACTs, survival in MBM is significantly improved after surgery or SRS even in patients with advanced and uncontrolled systemic disease at the time of presentation, supporting an aggressive approach to MBM management.

The impact of current treatment modalities on the outcomes of patients with melanoma brain metastases: A systematic review

Patients with melanoma brain metastases (MBM) still have a very poor prognosis. Several treatment modalities have been investigated in an attempt to improve the management of MBM. This review aimed to evaluate the impact of current treatments for MBM on patient‐ and tumor‐related outcomes, and to provide treatment recommendations for this patient population. A literature search in the databases PubMed, Embase, Web of Science and Cochrane was conducted up to January 8, 2019. Original articles published since 2010 describing patient‐ and tumor‐related outcomes of adult MBM patients treated with clearly defined systemic therapy were included. Information on basic trial demographics, treatment under investigation and outcomes (overall and progression‐free survival, local and distant control and toxicity) were extracted. We identified 96 eligible articles, comprising 95 studies. A large variety of treatment options for MBM were investigated, either used alone or as combined modality therapy. Combined modality therapy was investigated in 71% of the studies and resulted in increased survival and better distant/local control than monotherapy, especially with targeted therapy or immunotherapy. However, neurotoxic side‐effects also occurred more frequently. Timing appeared to be an important determinant, with the best results when radiotherapy was given before or during systemic therapy. Improved tumor control and prolonged survival can be achieved by combining radiotherapy with immunotherapy or targeted therapy. However, more randomized controlled trials or prospective studies are warranted to generate proper evidence that can be used to change the standard of care for patients with MBM.

Upfront Surgical Resection of Melanoma Brain Metastases Provides a Bridge Toward Immunotherapy-Mediated Systemic Control

BACKGROUND

Immune checkpoint blockade has systemic efficacy in patients with metastatic melanoma, including those with brain metastases (MBMs). However, immunotherapy-induced intracranial tumoral inflammation can lead to neurologic compromise, requiring steroids, which abrogate the systemic efficacy of this approach. We investigated whether upfront neurosurgical resection of MBM is associated with a therapeutic advantage when performed prior to initiation of immunotherapy.

MATERIAL AND METHODS

An institutional review board-approved, retrospective study identified 142 patients with MBM treated with immune checkpoint blockade between 2010 and 2016 at Massachusetts General Hospital, of whom 79 received surgery. Patients were classified based on the temporal relationship between immunotherapy, surgery, and development of central nervous system metastases. Overall survival (OS) was calculated from the date of diagnosis of MBM until death from any cause. Multivariate model building included a prognostic Cox model of OS, the effect of immunotherapy and surgical sequencing on OS, and the effect of immunotherapy and radiation sequencing on OS.

RESULTS

The 2-year overall survival for patients treated with cytotoxic T-lymphocyte antigen 4, programmed death 1, or combinatorial blockade was 19%, 54%, and 57%, respectively. Among immunotherapy-naïve melanoma brain metastases, surgery followed by immunotherapy had a median survival of 22.7 months (95% confidence interval [CI], 12.6-39.2) compared with 10.8 months for patients treated with immunotherapy alone (95% CI, 7.8-16.3) and 9.4 months for patients treated with immunotherapy followed by surgery (95% CI, 4.1 to ∞; p = .12). On multivariate analysis, immunotherapy-naïve brain metastases treated with immunotherapy alone were associated with increased risk of death (hazard ratio, 1.72; 95% CI, 1.00-2.99) compared with immunotherapy-naïve brain metastases treated with surgery followed by immunotherapy.

CONCLUSION

In treatment-naïve patients, early surgical resection for local control should be considered prior to commencing immunotherapy. A prospective, randomized trial comparing the sequence of surgery and immunotherapy for treatment-naïve melanoma brain metastases is warranted.

IMPLICATIONS FOR PRACTICE

In this retrospective study of 142 patients with melanoma brain metastases treated with immune checkpoint blockade, the development of melanoma brain metastases following immunotherapy was associated with decreased survival compared with diagnosis of immunotherapy-naïve brain metastases. The benefit of surgical intervention was seen in immunotherapy-naïve brain metastases in contrast to brain metastases that developed on immunotherapy. These results suggest that upfront local control with surgery for immunotherapy-naïve melanoma brain metastasis may provide a bridge toward immunotherapy-mediated systemic control.

Indications for the surgical resection of stage IV disease

Tumor biology and careful patient selection weigh heavily in determining the appropriate role of surgical resection in stage IV melanoma. Historically, surgical resection for highly selected patients with metastatic melanoma was the only treatment modality associated with improved long-term survival and the ability to provide palliation. With the new age of effective systemic therapies, the treatment of metastatic melanoma has become more intricate and future work is needed to better define the role for surgery within the current treatment paradigm.

Brain metastases: epidemiology

Brain metastases (BM) are the most commonly diagnosed type of central nervous system tumor in the United States. Estimates of the frequency of BM vary significantly, as there is no nationwide reporting system for metastases. BM may be the first sign of a previously undiagnosed cancer, or occur years or decades after the primary cancer was diagnosed. Incidence of BM varies significantly by primary cancer site. Lung, breast, and melanoma continue to be the leading cause of BM. These tumors are increasingly more common as new therapeutics, advanced imaging, and improved screening have led to lengthened survival after primary diagnosis for cancer patients. BM are difficult to treat, and for most individuals the diagnosis of BM generally portends a poor prognosis.

The biology and therapeutic management of melanoma brain metastases

The recent years have seen significant progress in the development of systemic therapies to treat patients with advanced melanoma. Use of these new treatment modalities, which include immune checkpoint inhibitors and small molecule BRAF inhibitors, lead to increased overall survival and better outcomes. Although revolutionary, these therapies are often less effective against melanoma brain metastases, and frequently the CNS is the major site of treatment failure. The development of brain metastases remains a serious complication of advanced melanoma that is associated with significant morbidity and mortality. New approaches to both prevent the development of brain metastases and treat established disease are urgently needed. In this review we will outline the mechanisms underlying the development of melanoma brain metastases and will discuss how new insights into metastasis biology are driving the development of new therapeutic strategies. Finally, we will describe the latest data from the ongoing clinical trials for patients with melanoma brain metastases.

Challenges in the delivery of therapies to melanoma brain metastases

Brain metastases are a major cause of morbidity and mortality in patients with advanced melanoma. Recent approval of several molecularly-targeted agents and biologics has brought hope to patients with this previously untreatable disease. However, patients with symptomatic melanoma brain metastases have often been excluded from pivotal clinical trials. This may be in part attributed to the fact that several of the approved small molecule molecularly-targeted agents are substrates for active efflux at the blood-brain barrier, limiting their effective delivery to brain metastases. We believe that successful treatment of melanoma brain metastases will depend on the ability of these agents to traverse the blood-brain barrier and reach micrometastases that are often not clinically detectable. Moreover, overcoming the emergence of a unique pattern of resistance, possibly through adequate delivery of combination targeted therapies in brain metastases will be important in achieving a durable response. These concepts, and the current challenges in the delivery of new treatments to melanoma brain metastases, are discussed in this review.

Embracing rejection: Immunologic trends in brain metastasis

Brain metastases represent the most common type of brain tumor. These tumors offer a dismal prognosis and significantly impact quality of life for patients. Their capacity for central nervous system (CNS) invasion is dependent upon induced disruptions to the blood-brain barrier (BBB), alterations to the brain microenvironment, and mechanisms for escaping CNS immunosurveillance. In the emerging era of immunotherapy, understanding how metastases are influenced by the immunologic peculiarities of the CNS will be crucial to forging therapeutic advances. In this review, the immunology of brain metastasis is explored.

Management of melanoma brain metastases

Relapses in the brain remain a major obstacle to cure in many patients with advanced melanoma. At present, the management of melanoma brain metastases continues to rely heavily on surgical and radiotherapeutic interventions, which have become safer and more effective with modern imaging, surgery and radiation technologies. Additionally, novel targeted and immunotherapeutic agents, shown to generate meaningful intracranial response and survival benefit in patients with melanoma brain metastases when compared with historical controls, expand systemic treatment options for this subset of patients. These systemic therapies become particularly important when intracranial disease burden precludes neuro- or radio-surgery. Considerable multidisciplinary research effort is ongoing to improve outcomes for melanoma patients with brain metastases, a key challenge in the management of advanced melanoma.

Metastasectomy for stage IV melanoma

Metastatic melanoma has an unpredictable natural history but a predictably high mortality. Despite recent advances in systemic therapy, many patients do not respond, or develop resistance to drug therapy. Surgery has consistently shown good outcomes in appropriately selected patients. It is likely to be even more successful in the era of more effective medical treatment. Surgery should remain a strongly considered option for metastatic melanoma.

[Locoregional treatments of brain metastases for patients with metastatic cutaneous melanoma: French national guidelines]

INTRODUCTION

The management of metastatic cutaneous melanoma is changing, marked by innovative therapies. However, their respective use and place in the therapeutic strategy continue to be debated by healthcare professionals.

OBJECTIVE

The French national cancer institute has led a national clinical practice guideline project since 2008. It has carried out a review of these modalities of treatment and established recommendations.

METHODS

The clinical practice guidelines development process is based on systematic literature review and critical appraisal by experts. The recommendations are thus based on the best available evidence and expert agreement. Prior to publication, the guidelines are reviewed by independent practitioners in cancer care delivery.

RESULTS

This article presents the results of bibliographic search, the conclusions of the literature and the recommendations concerning locoregional treatments of brain metastases for patients with metastatic cutaneous melanoma.

Epigenome-wide DNA methylation landscape of melanoma progression to brain metastasis reveals aberrations on homeobox D cluster associated with prognosis

Melanoma brain metastasis (MBM) represents a frequent complication of cutaneous melanoma. Despite aggressive multi-modality therapy, patients with MBM often have a survival rate of <1 year. Alteration in DNA methylation is a major hallmark of tumor progression and metastasis; however, it remains largely unexplored in MBM. In this study, we generated a comprehensive DNA methylation landscape through the use of genome-wide copy number, DNA methylation and gene expression data integrative analysis of melanoma progression to MBM. A progressive genome-wide demethylation in low CpG density and an increase in methylation level of CpG islands according to melanoma progression were observed. MBM-specific partially methylated domains (PMDs) affecting key brain developmental processes were identified. Differentially methylated CpG sites between MBM and lymph node metastasis (LNM) from patients with good prognosis were identified. Among the most significantly affected genes were the HOX family members. DNA methylation of HOXD9 gene promoter affected transcript and protein expression and was significantly higher in MBM than that in early stages. A MBM-specific PMD was identified in this region. Low methylation level of this region was associated with active HOXD9 expression, open chromatin and histone modifications associated with active transcription. Demethylating agent induced HOXD9 expression in melanoma cell lines. The clinical relevance of this finding was verified in an independent large cohort of melanomas (n = 145). Patients with HOXD9 hypermethylation in LNM had poorer disease-free and overall survival. This epigenome-wide study identified novel methylated genes with functional and clinical implications for MBM patients.

A new role of vemurafenib as a neoadjuvant treatment of axillary and brain melanoma metastases

Vemurafenib is approved by the FDA for the management of unresectable or metastatic melanoma. However, its role as a neoadjuvant therapy has not been determined. We present the first documented case in which vemurafenib induced complete tumor necrosis of both lymph node and brain metastases within one month or less, an outcome that indicated that the patient was a good candidate for excisional surgery.

Advances in therapy for melanoma brain metastases

Melanoma cells frequently metastasize to the brain, and approximately 50% of patients with metastatic melanoma develop intracranial disease. Historically, central nervous system dissemination has portended a very poor prognosis. Recent advances in systemic therapies for melanoma, supported by improved local therapy control of brain lesions, have resulted in better median survival for these patients. We review current local and systemic approaches for patients with melanoma brain metastases.

Ipilimumab and radiation therapy for melanoma brain metastases

Ipilimumab, an antibody that enhances T-cell activation, may augment immunogenicity of tumor cells that are injured by radiation therapy. We hypothesized that patients with melanoma brain metastasis treated with both ipilimumab and radiotherapy would have improved overall survival, and that the sequence of treatments may affect disease control in the brain. We analyzed the clinical and radiographic records of melanoma patients with brain metastases who were treated with whole brain radiation therapy or stereotactic radiosurgery between 2005 and 2012. The hazard ratios for survival were estimated to assess outcomes as a function of ipilimumab use and radiation type. Seventy patients were identified, 33 of whom received ipilimumab and 37 who did not. The patients who received ipilimumab had a censored median survival of 18.3 months (95% confidence interval 8.1–25.5), compared with 5.3 months (95% confidence interval 4.0–7.6) for patients who did not receive ipilimumab. Ipilimumab and stereotactic radiosurgery were each significant predictors of improved overall survival (hazard ratio = 0.43 and 0.45, with P = 0.005 and 0.008, respectively). Four of 10 evaluable patients (40.0%) who received ipilimumab prior to radiotherapy demonstrated a partial response to radiotherapy, compared with two of 22 evaluable patients (9.1%) who did not receive ipilimumab. Ipilimumab is associated with a significantly reduced risk of death in patients with melanoma brain metastases who underwent radiotherapy, and this finding supports the need for multimodality therapy to optimize patient outcomes. Prospective studies are needed and are underway.

Optimal management of metastatic melanoma: current strategies and future directions

Melanoma is increasing in incidence and remains a major public health threat. Although the disease may be curable when identified early, advanced melanoma is characterized by widespread metastatic disease and a median survival of less than 10 months. In recent years, however, major advances in our understanding of the molecular nature of melanoma and the interaction of melanoma cells with the immune system have resulted in several new therapeutic strategies that are showing significant clinical benefit. Current therapeutic approaches include surgical resection of metastatic disease, chemotherapy, immunotherapy, and targeted therapy. Dacarbazine, interleukin-2, ipilimumab, and vemurafenib are now approved for the treatment of advanced melanoma. In addition, new combination chemotherapy regimens, monoclonal antibodies blocking the programmed death-1 (PD-1)/PD-ligand 1 pathway, and targeted therapy against CKIT, mitogen-activated protein/extracellular signal-regulated kinase (MEK), and other putative signaling pathways in melanoma are beginning to show promise in early-phase clinical trials. Further research on these modalities alone and in combination will likely be the focus of future clinical investigation and may impact the outcomes for patients with advanced melanoma.

In vivo Modeling and Molecular Characterization: A Path Toward Targeted Therapy of Melanoma Brain Metastasis

Brain metastasis (B-Met) from melanoma remains mostly incurable and the main cause of death from the disease. Early stage clinical trials and case studies show some promise for targeted therapies in the treatment of melanoma B-Met. However, the progression-free survival for currently available therapies, although significantly improved, is still very short. The development of new potent agents to eradicate melanoma B-Met relies on the elucidation of the molecular mechanisms that allow melanoma cells to reach and colonize the brain. The discovery of such mechanisms depends heavily on pre-clinical models that enable the testing of candidate factors and therapeutic agents in vivo. In this review we summarize the effects of available targeted therapies on melanoma B-Met in the clinic. We provide an overview of existing pre-clinical models to study the disease and discuss specific molecules and mechanisms reported to modulate different aspects of melanoma B-Met and finally, by integrating both clinical and basic data, we summarize both opportunities and challenges currently presented to researchers in the field.

Intracerebral CpG immunotherapy with carbon nanotubes abrogates growth of subcutaneous melanomas in mice

PURPOSE

Recently, we showed that intratumoral delivery of low-dose, immunostimulatory CpG oligodeoxynucleotides conjugated with carbon nanotubes (CNT-CpG) was more effective than free CpG and not only eradicated intracranial (i.c.) gliomas but also induced antitumor immunity that protected mice from subsequent i.c. or systemic tumor rechallenge. Here, we examined whether the same "intracerebral immunotherapy" strategy could be applied to the treatment of metastatic brain tumors.

EXPERIMENTAL DESIGN

Mice with both i.c. and s.c. melanomas were injected intratumorally with CNT-CpG into either location. Antitumor responses were assessed by flow cytometry, bioluminescent imaging, and animal survival.

RESULTS

When given s.c., CNT-CpG response was mostly local, and it only modestly inhibited the growth of i.c. melanomas. However, i.c. CNT-CpG abrogated the growth of not only brain but also s.c. tumors. Furthermore, compared with s.c. injections, i.c. CNT-CpG elicited a stronger inflammatory response that resulted in more potent antitumor cytotoxicity and improved in vivo trafficking of effector cells into both i.c. and s.c. tumors. To investigate factors that accounted for these observations, CNT-CpG biodistribution and cellular inflammatory responses were examined in both tumor locations. Intracranial melanomas retained the CNT-CpG particles longer and were infiltrated by Toll-like receptor (TLR-9)-positive microglia. In contrast, myeloid-derived suppressive cells were more abundant in s.c. tumors. Although depletion of these cells before s.c. CNT-CpG therapy enhanced its cytotoxic responses, antitumor responses to brain melanomas were unchanged.

CONCLUSIONS

These findings suggest that intracerebral CNT-CpG immunotherapy is more effective than systemic therapy in generating antitumor responses that target both brain and systemic melanomas.