BRAF‐V600 mutational status affects recurrence patterns of melanoma brain metastasis

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.

High-risk histopathologic features in local advanced conjunctival melanoma

PURPOSE

To identify high-risk histopathologic and molecular features of local recurrence, nodal metastasis, distant metastasis (DM) and disease-specific death (DSD) in conjunctival melanoma (CoM).

METHODS

Ninety patients with pathologically diagnosed CoM between 2008 and 2023 were enrolled. Immunohistochemistry staining of BRAFV600E , NRASQ61R , CD117, PD-1 and PD-L1 was performed in 65 and 45 patients, respectively. Cox regression and Kaplan-Meier survival analysis were conducted to identify risk factors for local recurrence, nodal metastasis, DM and DSD.

RESULTS

Pathologically, ulceration (hazard ratio [HR]: 3.170; 95% CI: 1.312-7.659; p = 0.01) and regression (HR: 3.196; 95% CI: 1.094-9.335; p = 0.034) were risk factors for DM. Tumour thickness ≥ 4 mm (HR: 4.889; 95% CI: 1.846-12.946; p = 0.001) and regression (HR: 4.011; 95% CI: 1.464-10.991; p = 0.007) were risk factors for DSD. For patients with tumour thickness < 4 mm, the presence of ulceration indicated a higher risk of nodal metastasis (log-rank p = 0.0011), DM (log-rank p = 0.00051) and DSD (log-rank p = 0.02). Patients with regression (+)/tumour-infiltrating lymphocytes (TILs) (+) had a higher risk for DM (log-rank p = 0.011) and DSD (log-rank p = 0.0032). Molecularly, the positive rate of BRAFV600E , NRASQ61R , CD117, PD-1 and PD-L1 was 40.00% (26/65), 43.08% (28/65), 70.77% (46/65), 46.67% (21/45) and 28.89% (13/45), respectively. Positive BRAFV600E was identified as an independent risk factor for DM (HR: 2.533; 95% CI: 1.046-6.136, p = 0.039). The expression level of BRAFV600E was positively correlated with vascular invasion (p = 0.01), as well as the expression levels of PD-1 (p = 0.038) and PD-L1 (p = 0.049).

CONCLUSIONS

Tumour thickness ≥ 4 mm, ulceration, the coexistence of regression and TILs, and positive BRAFV600E were risk factors for poor prognosis of CoM patients. Besides, expression level of BRAFV600E was positively correlated with the expression levels of PD-1 and PD-L1.

The Effect of Non-Overlapping Somatic Mutations in BRAF, NRAS, NF1, or CKIT on the Incidence and Outcome of Brain Metastases during Immune Checkpoint Inhibitor Therapy of Metastatic Melanoma

Previous studies suggested that somatic BRAF and NRAS mutations in metastatic melanoma increase the risk for brain metastases. The risk related to other non-overlapping "driver" mutations is unknown. We performed a retrospective evaluation of the incidence, timing, and outcome of brain metastases in a population of melanoma patients that underwent uniform next-gen sequencing. All patients were treated with initial checkpoint inhibitor therapy. Seventeen of 88 patients (20.0%) developed brain metastases. Eleven patients had brain metastases at diagnosis (12.9%). These were all patients with BRAF V600 or NF1 mutations. Only six patients with NRAS, NF1, KIT, or BRAF mutations (including fusions/internal rearrangements experienced delayed CNS progression following immunotherapy (7.1%)). No "quadruple negative" patient developed brain metastases. Patients with brain metastases at diagnosis had a better outcome than those with delayed intracranial progression. Current predictive markers, (LDH, tumor mutation burden, and PDL1) were poorly correlated with the development of brain metastases. Treatment with immunotherapy appears to reduce the incidence of brain metastases. Next-gen molecular sequencing of tumors in metastatic melanoma patients was useful in identifying genetic subpopulations with an increased or reduced risk of brain metastases. This may allow eventual personalization of screening strategies.

Prognostic Value of Baseline 18F-FDG PET/CT to Predict Brain Metastasis Development in Melanoma Patients

To investigate the value of 18F-FDG-PET/CT in predicting the occurrence of brain metastases in melanoma patients, in this retrospective study 201 consecutive patients with pathology-proven melanoma, between 2008 and 2021, were reviewed. Those who underwent 18F-FDG-PET/CT for initial staging were considered eligible. Baseline assessment included histopathology, 18F-FDG-PET/CT, and brain MRI. Also, all patients had serial follow-ups for diagnosing brain metastasis development. Baseline 18F-FDG-PET/CT parameters were analysed using competing risk regression models to analyze their correlation with the occurrence of brain metastases. Overall, 159 patients entered the study. The median follow-up was six years. Among clinical variables, the initial M-stage and TNM-stage were significantly correlated with brain metastasis. Regarding 18F-FDG-PET/CT parameters, regional metastatic lymph node uptake values, as well as prominent SULmax (pSULmax) and prominent SUVmean (pSUVmean), were significantly correlated with the outcome. Cumulative incidences were 10% (6.3-16%), 31% (24.4-38.9%), and 35.2% (28.5-43.5%) after 1, 5, and 10 years. There were significant correlations between pSULmax (p-value < 0.001) and pSULpeak (p-value < 0.001) and the occurrence of brain metastases. The higher these values, the sooner the patient developed brain metastases. Thus, baseline 18F-FDG-PET/CT may have the potential to predict brain metastasis in melanoma patients. Those with high total metabolic activity should undergo follow-up/complementary evaluations, such as brain MRI.

Successes and challenges in modeling heterogeneous BRAFV600E mutated central nervous system neoplasms

Central nervous system (CNS) neoplasms are difficult to treat due to their sensitive location. Over the past two decades, the availability of patient tumor materials facilitated large scale genomic and epigenomic profiling studies, which have resulted in detailed insights into the molecular underpinnings of CNS tumorigenesis. Based on results from these studies, CNS tumors have high molecular and cellular intra-tumoral and inter-tumoral heterogeneity. CNS cancer models have yet to reflect the broad diversity of CNS tumors and patients and the lack of such faithful cancer models represents a major bottleneck to urgently needed innovations in CNS cancer treatment. Pediatric cancer model development is lagging behind adult tumor model development, which is why we focus this review on CNS tumors mutated for BRAFV600E which are more prevalent in the pediatric patient population. BRAFV600E-mutated CNS tumors exhibit high inter-tumoral heterogeneity, encompassing clinically and histopathological diverse tumor types. Moreover, BRAFV600E is the second most common alteration in pediatric low-grade CNS tumors, and low-grade tumors are notoriously difficult to recapitulate in vitro and in vivo. Although the mutation predominates in low-grade CNS tumors, when combined with other mutations, most commonly CDKN2A deletion, BRAFV600E-mutated CNS tumors are prone to develop high-grade features, and therefore BRAFV600E-mutated CNS are a paradigm for tumor progression. Here, we describe existing in vitro and in vivo models of BRAFV600E-mutated CNS tumors, including patient-derived cell lines, patient-derived xenografts, syngeneic models, and genetically engineered mouse models, along with their advantages and shortcomings. We discuss which research gaps each model might be best suited to answer, and identify those areas in model development that need to be strengthened further. We highlight areas of potential research focus that will lead to the heightened predictive capacity of preclinical studies, allow for appropriate validation, and ultimately improve the success of "bench to bedside" translational research.

Treatment experience with encorafenib plus binimetinib for BRAF V600-mutant metastatic melanoma: management insights for clinical practice

For patients with locally advanced or metastatic melanoma who have BRAF V600 activating mutations, combination therapy with BRAF and MEK inhibitors is now the standard of care. The combination of encorafenib, a highly selective adenosine triphosphate-competitive BRAF inhibitor, plus binimetinib, a potent, selective, allosteric, non-adenosine triphosphate-competitive MEK1/2 inhibitor, was approved by the US Food and Drug Administration for unresectable or metastatic melanoma with BRAF V600E or V600K mutations based on data from the phase III COLUMBUS study (NCT01909453). Clinical data evaluating BRAF and MEK inhibitor combinations in advanced melanoma indicate a specific profile of adverse events that includes serious retinopathy, skin disorders, and cardiovascular toxicities. Here we provide an overview of the rationale for combining BRAF and MEK inhibitors for the treatment of melanoma, long-term safety results from COLUMBUS, and guidance on managing the most common adverse events associated with this combination based on clinical experience. Proactive and appropriate management of adverse events can allow for longer treatment durations and may result in better treatment outcomes.

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.

Burden and Risk Factors of Brain Metastases in Melanoma: A Systematic Literature Review

Melanoma can frequently metastasize to the brain with severe consequences. However, variation of melanoma brain metastases (MBM) development among populations is not well studied, and underlying mechanisms and risk factors for MBM development are not consistently documented. We conducted a systematic literature review (SLR) including a total of 39 articles to evaluate the proportion of melanoma patients who are diagnosed with, or develop, brain metastases, and summarize the risk factors of MBM. The average proportion of MBM was calculated and weighted by the sample size of each study. Meta-analyses were conducted for the selected risk factors using a random-effects model. The proportion of MBM at diagnosis was 33% (975 with MBM out of 2948 patients) among patients with cutaneous melanoma (excluding acral) and 23% (651/2875) among patients with cutaneous mixed with other types of melanoma. The proportion at diagnosis was lower among populations with mucosal (9/96, 9%) or uveal (4/184, 2%) melanoma and among populations outside the United States and Europe. Meta-analysis demonstrated that male vs. female gender and left-sided tumors vs. right-sided were significantly associated with increased risk of melanoma brain metastases. These data may help clinicians to assess an individual patient's risk of developing melanoma brain metastases.

Systematic literature review and meta-analysis of clinical outcomes and prognostic factors for melanoma brain metastases

Background

More than 60% of all stage IV melanoma patients develop brain metastases, while melanoma brain metastases (MBM) is historically difficult to treat with poor prognosis.

Objectives

To summarize clinical outcomes and prognostic factors in MBM patients.

Methods

A systematic review with meta-analysis was conducted, and a literature search for relevant studies was performed on November 1, 2020. Weighted average of median overall survival (OS) was calculated by treatments. The random-effects model in conducting meta-analyses was applied.

Results

A total of 41 observational studies and 12 clinical trials with our clinical outcomes of interest, and 31 observational studies addressing prognostic factors were selected. The most common treatments for MBM were immunotherapy (IO), MAP kinase inhibitor (MAPKi), stereotactic radiosurgery (SRS), SRS+MAPKi, and SRS+IO, with median OS from treatment start of 7.2, 8.6, 7.3, 7.3, and 14.1 months, respectively. Improved OS was observed for IO and SRS with the addition of IO and/or MAPKi, compared to no IO and SRS alone, respectively. Several prognostic factors were found to be significantly associated with OS in MBM.

Conclusion

This study summarizes pertinent information regarding clinical outcomes and the association between patient characteristics and MBM prognosis.

Correlation of MRI signal characteristics of intracranial melanoma metastases with BRAF mutation status

BRAF V600 mutations (BRAFmut) are associated with more pigmentation in primary melanomas, but data on melanin content of metastases are limited. This study compares signal characteristics of BRAFmut and BRAF-wildtype (BRAFwt) intracranial melanoma metastases (IMM). MRI brain examinations at first diagnosis of IMM were identified, all performed at 3-Tesla including 1 mm volumetric pre- and postcontrast T1-weighted imaging and susceptibility-weighted imaging (SWI). Individual metastases were assessed by a neuroradiologist, stratified by size (≥10 mm, 'larger', vs. 2-9 mm, 'small'; up to 10 per group); presence of intrinsic T1-hyperintensity (T1H) and, if present, whether confidently attributable to melanin as opposed to haemorrhage; evidence of haemorrhage; presence of central necrosis. A total of 267 IMM in 73 patients were assessed (87 larger IMM, 180 small). The proportion of larger IMM was similar in both groups (31% BRAFmut and 36% BRAFwt). In small IMM, MRI evidence of melanin was more common in BRAFmut patients (42% vs. 26%; P = 0.038). Haemorrhage was more common in larger IMM (51%, vs. 20% of small IMM; P < 0.0001), but did not differ based on BRAF status. Central necrosis was more common in larger IMM (44% vs. 7%; P < 0.0001) and in BRAFmut IMM (23% vs. 11%; P = 0.011). In the BRAFmut cohort, central necrosis was more common in patients without previous anti-BRAF therapy (33% vs. 7%; P = 0.0001). T1H attributable to melanin is only slightly more common in BRAFmut IMM than BRAFwt. Higher rates of central necrosis in BRAFmut patients without previous anti-BRAF therapy suggest that anti-BRAF therapy may affect the patterns of IMM growth.

Emerging Role of Deubiquitinating Enzymes (DUBs) in Melanoma Pathogenesis

Metastatic melanoma is the leading cause of death from skin cancer. Therapies targeting the BRAF oncogenic pathway and immunotherapies show remarkable clinical efficacy. However, these treatments are limited to subgroups of patients and relapse is common. Overall, the majority of patients require additional treatments, justifying the development of new therapeutic strategies. Non-genetic and genetic alterations are considered to be important drivers of cellular adaptation mechanisms to current therapies and disease relapse. Importantly, modification of the overall proteome in response to non-genetic and genetic events supports major cellular changes that are required for the survival, proliferation, and migration of melanoma cells. However, the mechanisms underlying these adaptive responses remain to be investigated. The major contributor to proteome remodeling involves the ubiquitin pathway, ubiquitinating enzymes, and ubiquitin-specific proteases also known as DeUBiquitinases (DUBs). In this review, we summarize the current knowledge regarding the nature and roles of the DUBs recently identified in melanoma progression and therapeutic resistance and discuss their potential as novel sources of vulnerability for melanoma therapy.

Clinical Development of BRAF plus MEK Inhibitor Combinations

Genomic profiling shows that many solid tumors are characterized by specific driver aberrations, and this has expanded the therapeutic options for many patients. The mitogen-activated protein kinase (MAPK) pathway is a key cell signaling pathway involved in regulating cellular growth, proliferation, and survival. Driver mutations in the BRAF gene, a key player in the MAPK pathway, are described in multiple tumor types, including subsets of melanoma, non-small cell lung cancer (NSCLC), and anaplastic thyroid cancer (ATC), making BRAF a desirable target for inhibition. BRAF inhibitors have shown efficacy in several cancers; however, most patients eventually develop resistance. To delay or prevent resistance, combination therapy targeting BRAF and MEK, a downstream signaling target of BRAF in the MAPK pathway, was evaluated and demonstrated synergistic benefit. BRAF and MEK inhibitor combinations have been approved for use in various cancers by the US FDA. We review the clinical data for various BRAF plus MEK combination regimens in three cancer types with underlying BRAF driver mutations: melanoma, NSCLC, and ATC. We also discuss practical treatment considerations and management of selected combination therapy toxicities.

Virtual biopsy using MRI radiomics for prediction of BRAF status in melanoma brain metastasis

Brain metastases are common in patients with advanced melanoma and constitute a major cause of morbidity and mortality. Between 40% and 60% of melanomas harbor BRAF mutations. Selective BRAF inhibitor therapy has yielded improvement in clinical outcome; however, genetic discordance between the primary lesion and the metastatic tumor has been shown to occur. Currently, the only way to characterize the genetic landscape of a brain metastasis is by tissue sampling, which carries risks and potential complications. The aim of this study was to investigate the use of radiomics analysis for non-invasive identification of BRAF mutation in patients with melanoma brain metastases, based on conventional magnetic resonance imaging (MRI) data. We applied a machine-learning method, based on MRI radiomics features for noninvasive characterization of the BRAF status of brain metastases from melanoma (BMM) and applied it to BMM patients from two tertiary neuro-oncological centers. All patients underwent surgical resection for BMM, and their BRAF mutation status was determined as part of their oncological work-up. Their routine preoperative MRI study was used for radiomics-based analysis in which 195 features were extracted and classified according to their BRAF status via a support vector machine. The BRAF status of 53 study patients, with 54 brain metastases (25 positive, 29 negative for BRAF mutation) was predicted with mean accuracy = 0.79 ± 0.13, mean precision = 0.77 ± 0.14, mean sensitivity = 0.72 ± 0.20, mean specificity = 0.83 ± 0.11 and with a 0.78 area under the receiver operating characteristic curve for positive BRAF mutation prediction. Radiomics-based noninvasive genetic characterization is feasible and should be further verified using large prospective cohorts.

BRAFi induced demethylation of miR-152-5p regulates phenotype switching by targeting TXNIP in cutaneous melanoma

Treatment of advanced BRAFV600-mutant melanoma using BRAF inhibitors (BRAFi) eventually leads to drug resistance and selects for highly metastatic tumor cells. We compared the most differentially dysregulated miRNA expression profiles of vemurafenib-resistant and highly-metastatic melanoma cell lines obtained from GEO DataSets. We discovered miR-152-5p was a potential regulator mediating melanoma drug resistance and metastasis. Functionally, knockdown of miR-152-5p significantly compromised the metastatic ability of BRAFi-resistant melanoma cells and overexpression of miR-152-5p promoted the formation of slow-cycling phenotype. Furthermore, we explored the cause of how and why miR-152-5p affected metastasis in depth. Mechanistically, miR-152-5p targeted TXNIP which affected metastasis and BRAFi altered the methylation status of MIR152 promoter. Our study highlights the crucial role of miR-152-5p on melanoma metastasis after BRAFi treatment and holds significant implying that discontinuous dosing strategy may improve the benefit of advanced BRAFV600-mutant melanoma patients.

Purely Meningeal Intracranial Relapse of Melanoma Brain Metastases After Surgical Resection and Immunotherapy as a Unique Disease Progression Pattern: Our Experience and Review of the Literature

BACKGROUND

We present a case of 72-year-old man with a history of metastatic melanoma diagnosed in 2015 presenting a stable disease in treatment with dabrafenib.

CASE DESCRIPTION

The patient had been surgically treated for a presumed intracranial parietooccipital metastasis. He presented 1 month later with a meningeal lesion associated with a subdural hematoma. A second surgical treatment confirmed the diagnosis of meningeal recurrence of metastatic melanoma.

CONCLUSIONS

The most recent literature lacks studies defining the clinical phenomena of an early recurrence of intracranial melanoma with de novo involvement of dural compartment in patients in treatment with a target immunotherapy. The aim of this present study is to report a case of early recurrence of intracranial melanoma metastases with evidence of fast immunohistochemical and macroscopical mutation of pathologic elements, with an analysis of literature that shows the lack of well-described occurrences.

Activated Hgf-Met Signaling Cooperates with Oncogenic BRAF to Drive Primary Cutaneous Melanomas and Angiotropic Lung Metastases in Mice

Oncogenic mutations in the BRAF kinase gene represent the most frequent genomic driver in acquired melanocytic nevi and in cutaneous melanomas. It is currently thought that oncogene-induced senescence and cell cycle arrest limit the ability of oncogenic BRAF to promote melanocyte proliferation in benign nevi. The molecular and cellular mechanisms that allow an oncogenic BRAF mutation to fully transform melanocytes into invasively growing melanoma cells that are able to metastasize systemically are only partially understood. In this study, we show in a genetic mouse model that constitutively enhanced Hgf-Met signaling cooperates with oncogenic BRAF to drive tumor development and metastatic spread. Activation of oncogenic BRAF in mice with transgenic Hgf overexpression and an oncogenic CDK4 germline mutation accelerated and increased the development of primary cutaneous melanomas. Primary melanomas showed considerable phenotypic heterogeneity with frequent signs of dedifferentiation. BRAF activation in Hgf-CDK4 mice also increased the number of lung metastases. Melanoma cells showed a pronounced angiotropic growth pattern both at the invasive front in primary tumors and in metastatic lesions of the lung. Taken together, our work supports the notion that activated Hgf-Met signaling and oncogenic BRAF can cooperate in melanoma pathogenesis.

The Role of Melanoma Cell-Stroma Interaction in Cell Motility, Invasion, and Metastasis

The importance of studying cancer cell invasion is highlighted by the fact that 90% of all cancer-related mortalities are due to metastatic disease. Melanoma metastasis is driven fundamentally by aberrant cell motility within three-dimensional or confined environments. Within this realm of cell motility, cytokines, growth factors, and their receptors are crucial for engaging signaling pathways, which both mediate crosstalk between cancer, stromal, and immune cells in addition to interactions with the surrounding microenvironment. Recently, the study of the mechanical biology of tumor cells, stromal cells and the mechanics of the microenvironment have emerged as important themes in driving invasion and metastasis. While current anti-melanoma therapies target either the MAPK signaling pathway or immune checkpoints, there are no drugs available that specifically inhibit motility and thus invasion and dissemination of melanoma cells during metastasis. One of the reasons for the lack of so-called "migrastatics" is that, despite decades of research, the precise biology of metastatic disease is still not fully understood. Metastatic disease has been traditionally lumped into a single classification, however what is now emergent is that the biology of melanoma metastasis is highly diverse, heterogeneous and exceedingly dynamic-suggesting that not all cases are created equal. The following mini-review discusses melanoma heterogeneity in the context of the emergent theme of mechanobiology and how it influences the tumor-stroma crosstalk during metastasis. Thus, highlighting future therapeutic options for migrastatics and mechanomedicines in the prevention and treatment of metastatic melanoma.

Patterns of disease control and survival in patients with melanoma brain metastases undergoing immune-checkpoint blockade

OBJECTIVES

Immune-checkpoint blockers (ICBs) significantly prolong overall survival (OS) in patients with advanced melanoma. Limited data are available on the efficacy and clinical benefit in patients with melanoma brain metastases (MBMs). The aim of this study was to determine whether ICB is active in an unselected cohort treated of patients with known brain metastases and if disease control correlates with the survival.

METHODS

A total of 385 patients with metastatic malignant melanoma treated with ICB as monotherapy between 2005 and 2017 in two tertiary referral centres were included. Patient records were searched for the development of brain metastases. Demographic and clinical data of all patients were collected retrospectively.

RESULTS

We identified 177 patients with MBM who received ICBs (ipilimumab, nivolumab, pembrolizumab). Patients with and without brain metastases received similar ICB regimens. Prognosis was inferior in patients with brain metastases; patients with >1 brain metastasis showed even poorer survival. For extracranial (ec) metastases, disease control was associated with improved survival. However, when comparing patients with intracranial (ic) disease control during immunotherapy to patients with ic disease progression, no difference in OS could be observed.

CONCLUSIONS

In our study, ec disease control was the dominant predictive factor for OS in both patients with or without melanoma brain metastases. These data indicate that clinical trials in melanoma patients with brain metastases should address end-points such as symptom control, quality of life or OS in addition to ic response rates.

Risk factors for development of melanoma brain metastasis and disease progression: a single-center retrospective analysis

Melanoma metastasis to the brain is associated with a poor prognosis. We sought to determine patient demographics and primary tumor factors associated with the development of brain metastasis (BM) and survival. We also investigated whether the BM detection setting (routine screening vs. symptomatic presentation) affected clinical outcomes. A database of melanoma patients seen from 1999 to 2015 at our institution was reviewed to identify patients who developed BM. Patients with BM were matched by initial stage with patients who did not develop BM as a control group. Patient demographics, primary tumor characteristics, and clinical outcomes were analyzed. A total of 123 patients with BM were matched by initial presenting stage to 237 patients without BM. The characteristics of the primary melanoma tumor associated with BM development included location on the scalp (P=0.030), nodular histologic type (P=0.020), and Breslow depth more than 4 mm (P=0.048), whereas location on the leg was associated with decreased BM risk (P=0.006). In patients with BM, time to first recurrence for melanomas of the scalp was significantly shorter (10.8 vs. 24.8 months, P=0.007) than nonscalp head and neck tumors. Patient stage, tumor depth, nodular type, and ulceration were also associated with worse clinical outcomes. There were no differences in the clinical outcomes between patients whose BM were detected upon routine screening versus those detected upon symptomatic presentation. In summary, factors predictive of development of BM included primary scalp location, nodular type, and depth. In BM patients, scalp location, stage, tumor depth, nodular type, and ulceration, but not detection setting, were associated with worse clinical outcomes.

Tumour mutation status and sites of metastasis in patients with cutaneous melanoma

Background:

Cutaneous melanoma can metastasise haematogenously and/or lymphogenously to form satellite/in-transit, lymph node or distant metastasis. This study aimed to determine if BRAF and NRAS mutant and wild-type tumours differ in their site of first tumour metastasis and anatomical metastatic pathway.

Methods:

Prospective cohort of patients with a histologically confirmed primary cutaneous melanoma at three tertiary referral centres in Melbourne, Australia from 2010 to 2015. Multinomial regression determined clinical, histological and mutational factors associated with the site of first metastasis and metastatic pathway.

Results:

Of 1048 patients, 306 (29%) developed metastasis over a median 4.7 year follow-up period. 73 (24%), 192 (63%) and 41 (13%) developed distant, regional lymph node and satellite/in-transit metastasis as the first site of metastasis, respectively. BRAF mutation was associated with lymph node metastasis (adjusted RRR 2.46 95% CI 1.07–5.69, P=0.04) and sentinel lymph node positivity (adjusted odds ratio [aOR] OR 1.55, 95% CI 1.14–2.10, P=0.005). BRAF mutation and NRAS mutation were associated with increased odds of developing liver metastasis (aOR 3.09, 95% CI 1.49–6.42, P=0.003; aOR 3.17, 95% CI 1.32–7.58, P=0.01) and central nervous system (CNS) metastasis (aOR 4.65, 95% CI 2.23–9.69, P<0.001; aOR 4.03, 95% CI 1.72–9.44, P=0.001). NRAS mutation was associated with lung metastasis (aOR 2.44, 95% CI 1.21–4.93, P=0.01).

Conclusions:

BRAF mutation was found to be associated with lymph node metastasis as first metastasis and sentinel lymph node positivity. BRAF and NRAS mutations were associated with CNS and liver metastasis and NRAS mutation with lung metastasis. If these findings are validated in additional prospective studies, a role for heightened visceral organ surveillance may be warranted in patients with tumours harbouring these somatic mutations.

Melanoma Brain Metastasis: Mechanisms, Models, and Medicine

The development of brain metastases in patients with advanced stage melanoma is common, but the molecular mechanisms responsible for their development are poorly understood. Melanoma brain metastases cause significant morbidity and mortality and confer a poor prognosis; traditional therapies including whole brain radiation, stereotactic radiotherapy, or chemotherapy yield only modest increases in overall survival (OS) for these patients. While recently approved therapies have significantly improved OS in melanoma patients, only a small number of studies have investigated their efficacy in patients with brain metastases. Preliminary data suggest that some responses have been observed in intracranial lesions, which has sparked new clinical trials designed to evaluate the efficacy in melanoma patients with brain metastases. Simultaneously, recent advances in our understanding of the mechanisms of melanoma cell dissemination to the brain have revealed novel and potentially therapeutic targets. In this review, we provide an overview of newly discovered mechanisms of melanoma spread to the brain, discuss preclinical models that are being used to further our understanding of this deadly disease and provide an update of the current clinical trials for melanoma patients with brain metastases.