Innovative therapeutic strategies in the treatment of brain metastases

Predicting voxel-level dose distributions of single-isocenter volumetric modulated arc therapy treatment plan for multiple brain metastases

Purpose

Brain metastasis is a common, life-threatening neurological problem for patients with cancer. Single-isocenter volumetric modulated arc therapy (VMAT) has been popularly used due to its highly conformal dose and short treatment time. Accurate prediction of its dose distribution can provide a general standard for evaluating the quality of treatment plan. In this study, a deep learning model is applied to the dose prediction of a single-isocenter VMAT treatment plan for radiotherapy of multiple brain metastases.

Method

A U-net with residual networks (U-ResNet) is employed for the task of dose prediction. The deep learning model is first trained from a database consisting of hundreds of historical treatment plans. The 3D dose distribution is then predicted with the input of the CT image and contours of regions of interest (ROIs). A total of 150 single-isocenter VMAT plans for multiple brain metastases are used for training and testing. The model performance is evaluated based on mean absolute error (MAE) and mean absolute differences of multiple dosimetric indexes (DIs), including (D max and D mean) for OARs, (D 98, D 95, D 50, and D 2) for PTVs, homogeneity index, and conformity index. The similarity between the predicted and clinically approved plan dose distribution is also evaluated.

Result

For 20 tested patients, the largest and smallest MAEs are 3.3% ± 3.6% and 1.3% ± 1.5%, respectively. The mean MAE for the 20 tested patients is 2.2% ± 0.7%. The mean absolute differences of D 98, D 95, D 50, and D2 for PTV60, PTV52, PTV50, and PTV40 are less than 2.5%, 3.0%, 2.0%, and 3.0%, respectively. The prediction accuracy of OARs for D max and D mean is within 3.2% and 1.2%, respectively. The average DSC ranges from 0.86 to 1 for all tested patients.

Conclusion

U-ResNet is viable to produce accurate dose distribution that is comparable to those of the clinically approved treatment plans. The predicted results can be used to improve current treatment planning design, plan quality, efficiency, etc.

Impact of Heavy Metals on Glioma Tumorigenesis

Recently, an increase in the incidence of brain tumors has been observed in the most industrialized countries. This event triggered considerable interest in the study of heavy metals and their presence in the environment (air, water, soil, and food). It is probable that their accumulation in the body could lead to a high risk of the onset of numerous pathologies, including brain tumors, in humans. Heavy metals are capable of generating reactive oxygen, which plays a key role in various pathological mechanisms. Alteration of the homeostasis of heavy metals could cause the overproduction of reactive oxygen species and induce DNA damage, lipid peroxidation, and the alteration of proteins. A large number of studies have shown that iron, cadmium, lead, nickel, chromium, and mercury levels were significantly elevated in patients affected by gliomas. In this study, we try to highlight a possible correlation between the most frequently encountered heavy metals, their presence in the environment, their sources, and glioma tumorigenesis. We also report on the review of the relevant literature.

Stereotactic radiosurgery with whole brain radiotherapy combined with bevacizumab in the treatment of brain metastases from NSCLC

OBJECTIVE

Non-small cell lung cancer (NSCLC) patients who experience brain metastases are usually associated with poor prognostic outcomes. Whole-brain radiotherapy (WBRT) is one of the standard treatment strategies for NSCLC. It is interesting to combine angiogenesis inhibitors such as bevacizumab with radiation therapy. This study aimed to explore the efficacy and safety of stereotactic radiosurgery (SRS) with WBRT combined with bevacizumab in the treatment of brain metastases.

METHODS

A total of 21 patients with brain metastases from NSCLC were treated with bevacizumab and WBRT-SRS, while 28 patients were treated with WBRT-SRS only. The bevacizumab average dose was 5-7.5 mg/kg, approximately 2 cycles during radiotherapy. Tumor responses were evaluated every 3 months based on Response Evaluation Criteria in Solid Tumors version 1.1.

RESULTS

The median follow-up time was 13.5 months (range 2.7-88.4 months). The ORR and DCR of patients who received WBRT-SRS with or without bevacizumab were similar (p = 0.458, p = 0.382). OS(42.63 years VS 25.23 years, p = 0.02)and LPFS (39.53 years VS 23 years, p = 0.047)were better in WBRT-SRS with bevacizumab groups. After radiotherapy and 3 months after radiotherapy, the volume of peritumoral edema was significantly reduced in WBRT-SRS with bevacizumab groups(45.62 ± 24.03 cm³ vs 63.03 ± 25.44 cm³, p = 0.036;8.63 ± 6.87 cm³ vs 15.62 ± 10.58 cm³, p = 0.021). The main adverse reactions were similar in the two groups except for Venous thrombosis with bevacizumab (0 patients vs 5 patients, p = 0.006).

CONCLUSION

Bevacizumab with radiotherapy improved the overall efficacy and reduced the peritumoral edema of BM from NSCLC.

The Role of Nanotechnology in Spinal Cord Tumors

The efficacy of current multimodal therapeutic strategies in spinal cord tumors is limited by the lack of specific therapies. Importantly, sufficient amount of therapeutic materials should be concentrated in tumors in order to be efficient. Overcoming the blood-brain barrier is the major obstacle for chemotherapeutics, which cannot reach the tumor bed in efficacious doses. The intrinsic properties of nanoparticles make them suitable for activating numerous processes both at the cellular and subcellular levels, making them good candidates to be used for different purposes in medicine. Furthermore, the adaptability characteristic of NPs may enable them to pass through the blood-brain barrier and transport different pharmacological compounds. Nanoparticle systems provide prolonged drug delivery directly to the tumor or by functionalizing the material surface with peptides and ligands allowing the drug-loaded material to specifically target the tumor cells. In this chapter, various preclinical and/or clinical studies in treatment of spinal cord tumors are discussed.

The value of DTI: achieving high diagnostic performance for brain metastasis

BACKGROUND

The evaluation of brain metastases generally requires post-contrast MRI exam, but some patients have contraindication to contrast medium administration.

PURPOSE

To investigate the value of the MRI diffusion tensor imaging (DTI) for detection of metastatic brain tumor.

MATERIALS AND METHODS

We retrospectively analyzed the MRI data from 23 patients (13 males and 10 females) with brain metastases. The MRI protocol consisted in T1WI, T2WI, post-contrast 3DT1WI and DTI images (b = 1000) sequences. The brain metastatic lesions were counted in each of these sequences. We compared the advantages and limitations of different sequences in the brain metastases detection. The number of metastatic lesions identified on the contrast-enhanced 3DT1WI image is used as the reference. FA values were measured in the intratumoral, adjacent peritumoral and distant peritumoral edema area (PTEA) of brain metastasis, and the differences were statistically analyzed.

RESULTS

DTI can detect more brain metastatic lesions rather than T1WI and T2WI. The number of brain metastases on DTI is similar to post-contrast 3D T1WI. There is no statistical difference in the FA value change between the adjacent and distant PTEA.

CONCLUSION

The DTI original image can be used as an alternative examination for patients with contraindications to contrast-enhanced MRI. It has high sensitivity to intratumoral hemorrhage, which has advantage to detect brain metastatic lesions as compared with T1WI or T2WI images.

Bevacizumab for the treatment of non-small cell lung cancer patients with synchronous brain metastases

Bevacizumab is FDA-approved in the treatment of primary brain tumors, but its efficacy in patients with brain metastases could be better-studied. This study examines a population of non-small cell lung cancer (NSCLC) patients with synchronous brain metastases to identify predictors of the decision to use bevacizumab and survival following bevacizumab treatment. Primary cancer registry data were used to determine which NSCLC patients diagnosed in the years 2010 through 2012 had synchronous brain metastases at the time of diagnosis, and Medicare claims used to identify a population of patients treated with bevacizumab. Record of bevacizumab treatment was found for 81 and 666 patients with and without brain metastases, respectively. After adjusting for clinical and demographic characteristics, bevacizumab was associated with 0.88 times the hazard of mortality in the elderly NSCLC population (95% CI: 0.81–0.96, p: 0.003) and a corresponding hazard ratio of 0.75 in the population of elderly NSCLC patients with synchronous brain metastases (95% CI: 0.59–0.96, p: 0.020). Bevacizumab may benefit NSCLC patients with synchronous brain metastases more than it does patients without intracranial disease, possibly as a result of its multiple potential mechanisms of action simultaneously inhibiting angiogenesis and minimizing vasogenic edema.

Brain metastasis in pancreatic cancer: Two case reports

RATIONALE

Brain metastases are extremely rare for patients with pancreatic adenocarcinoma due to the poor prognoses. In the present study, we reported 2 cases of pancreatic adenocarcinoma with brain metastases.

PATIENT CONCERNS

The 1st patient was diagnosed asymptomatic brain metastasis by a follow-up brain magnetic resonance imaging (MRI) due to a medical history of subarachnoid hemorrhage. The 2nd patient experienced dizziness, neck pain, and seizure. Computed tomography (CT) was used for the diagnosis of brain metastasis because he was inserted a pacemaker.

DIAGNOSIS

In case 1, brain MRI revealed that a solitary brain metastasis 14-mm in size was identified at the cortico-medullary junction in the left frontal lobe. In case 2, brain enhanced CT revealed multiple brain metastases with calcification at the cerebral cortex. Times to develop central nervous system metastasis were 19 months and 33 months, respectively.

INTERVENTIONS

The 1st patient was treated with 45.2 Gy γ-knife irradiation for the solitary brain metastasis, and the 2nd patient was treated with supportive care due to the poor general condition.

OUTCOMES

The prognoses of these 2 patients were 13 months, and 32 days from the diagnosis of brain metastasis. The 1st patient did not experience complication of a γ-knife irradiation and brain metastasis was controlled until death.

LESSONS

The incidence of brain metastases from pancreatic adenocarcinoma is expected to increase due to prolonged survival from improved treatment. Therefore, increased awareness of brain involvement is necessary when neurological disorder is suspected in patients with advanced pancreatic cancer.

Bevacizumab and risk of intracranial hemorrhage in patients with brain metastases: a meta-analysis

Administration of bevacizumab to patients with brain metastases (BM) is controversial due to concerns about the increased risk of intracranial hemorrhage (ICH). This meta-analysis assessed whether the risk of ICH increases in BM patients receiving treatments that contain bevacizumab versus without. PubMed, Embase, Cochrane Library and annual meeting abstracts of the American Society of Clinical Oncology up to 13 November 2016 were searched for studies that referred to ICH complications due to bevacizumab in patients with BM. Eight studies involving 8713 patients were included in this analysis. Compared with the control arm without bevacizumab, the bevacizumab treatment arm did not exhibit a significant increase in ICH [odds ratio (OR) 1.20; 95% confidence intervals (CI) 0.69–2.09; P = 0.53]. Subgroup analyses with retrospective studies showed a similar result, although subgroup analyses with prospective studies failed. This meta-analysis revealed that bevacizumab does not significantly increase the risk of ICH in solid tumor patients with BM.

Cancer Immunotherapy Getting Brainy: Visualizing the Distinctive CNS Metastatic Niche to Illuminate Therapeutic Resistance

The advent of cancer immunotherapy (CIT) and its success in treating primary and metastatic cancer may offer substantially improved outcomes for patients. Despite recent advancements, many malignancies remain resistant to CIT, among which are brain metastases, a particularly virulent disease with no apparent cure. The immunologically unique niche of the brain has prompted compelling new questions in immuno-oncology such as the effects of tissue-specific differences in immune response, heterogeneity between primary tumors and distant metastases, and the role of spatiotemporal dynamics in shaping an effective anti-tumor immune response. Current methods to examine the immunobiology of metastases in the brain are constrained by tissue processing methods that limit spatial data collection, omit dynamic information, and cannot recapitulate the heterogeneity of the tumor microenvironment. In the current review, we describe how high-resolution, live imaging tools, particularly intravital microscopy (IVM), are instrumental in answering these questions. IVM of pre-clinical cancer models enables short- and long-term observations of critical immunobiology and metastatic growth phenomena to potentially generate revolutionary insights into the spatiotemporal dynamics of brain metastasis, interactions of CIT with immune elements therein, and influence of chemo- and radiotherapy. We describe the utility of IVM to study brain metastasis in mice by tracking the migration and growth of fluorescently-labeled cells, including cancer cells and immune subsets, while monitoring the physical environment within optical windows using imaging dyes and other signal generation mechanisms to illuminate angiogenesis, hypoxia, and/or CIT drug expression within the metastatic niche. Our review summarizes the current knowledge regarding brain metastases and the immune milieu, presents the current status of CIT and its prospects in targeting brain metastases to circumvent therapeutic resistance, and proposes avenues to utilize IVM to study CIT drug delivery and therapeutic efficacy in preclinical models that will ultimately facilitate novel drug discovery and innovative combination therapies.

Neurosurgical management of brain metastases

Brain metastases present a significant public health issue, affecting more than 100,000 patients per year in the U.S. and result in significant morbidity. Brain metastases can occur in a variety of clinical situations ranging from multiple brain metastases with uncontrolled systemic disease to a solitary metastasis in the setting of controlled systemic disease. Additionally, advances in genomics have broadened the opportunities for targeted treatment options and potentially more durable systemic responses. As such, the treatment of brain metastases is now more tailored and multimodal, involving systemic, radiation, and surgical therapies, often in combination. This review discusses the historical and current role of neurosurgical techniques in the treatment of brain metastases.

Downregulation of EGFR in a metastatic brain lesion of EGFR-mutated non-small cell lung cancer using a tyrosine kinase inhibitor: A case report

Brain metastasis is a common complication in patients with cancer, with lung cancer being the most frequent origin of brain metastases. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have begun to serve a pivotal role in lung cancer treatment and have been reported to demonstrate anticancer activity against brain metastases by penetrating the blood-brain barrier. The present study reports, to the best of our knowledge, the first case of EGFR-mutated non-small cell lung cancer (NSCLC) brain metastasis that was surgically resected while the lesion was responding to the EGFR-TKI erlotinib. The results of the present study demonstrated that EGFR-mutated NSCLC cells were able to evade the cytotoxic effect of EGFR-TKI by downregulating EGFR expression, without exhibiting the T790M EGFR mutation.

Use of Systemic Therapy Concurrent With Cranial Radiotherapy for Cerebral Metastases of Solid Tumors

The incidence of brain metastases of solid tumors is increasing. Local treatment of brain metastases is generally straightforward: cranial radiotherapy (e.g., whole-brain radiotherapy or stereotactic radiosurgery) or resection when feasible. However, treatment becomes more complex when brain metastases occur while other metastases, outside of the central nervous system, are being controlled with systemic therapy (chemotherapeutics, molecular targeted agents, or monoclonal antibodies). It is known that some anticancer agents can increase the risk for neurotoxicity when used concurrently with radiotherapy. Increased neurotoxicity decreases quality of life, which is undesirable in this predominantly palliative patient group. Therefore, it is of utmost importance to identify the compounds that should be temporarily discontinued when cranial radiotherapy is needed.This review summarizes the (neuro)toxicity data for combining systemic therapy (chemotherapeutics, molecular targeted agents, or monoclonal antibodies) with concurrent radiotherapy of brain metastases. Because only a limited amount of high-level data has been published, a risk assessment of each agent was done, taking into account the characteristics of each compound (e.g., lipophilicity) and the microenvironment of brain metastasis. The available trials suggest that only gemcitabine, erlotinib, and vemurafenib induce significant neurotoxicity when used concurrently with cranial radiotherapy. We conclude that for most systemic therapies, the currently available literature does not show an increase in neurotoxicity when these therapies are used concurrently with cranial radiotherapy. However, further studies are needed to confirm safety because there is no high-level evidence to permit definitive conclusions. The Oncologist 2017;22:222-235Implications for Practice: The treatment of symptomatic brain metastases diagnosed while patients are receiving systemic therapy continues to pose a dilemma to clinicians. Will concurrent treatment with cranial radiotherapy and systemic therapy (chemotherapeutics, molecular targeted agents, and monoclonal antibodies), used to control intra- and extracranial tumor load, increase the risk for neurotoxicity? This review addresses this clinically relevant question and evaluates the toxicity of combining systemic therapies with cranial radiotherapy, based on currently available literature, in order to determine the need to and interval to interrupt systemic treatment.

Clinical investigation into the initial diagnosis and treatment of 539 patients with stage IV lung cancer

Objective

The aim of the study was to analyze clinical data, including the types of pathologic classification, metastatic organs, treatment strategy, and prognosis of patients with stage IV lung cancer.

Methods

A retrospective analysis of the clinical features of 539 patients with stage IV lung cancer who were initially diagnosed and treated in 2009 was conducted. There were 146 cases of single organ metastases and 393 cases of multiple organ metastases. The Kaplan-Meier method and multivariate Cox regression analysis were performed to analyze the influence of age, pathological classification, metastatic organs, and treatment strategy on overall survival.

Results

The 1-, 2-, and 3-year survival rates were 64.2% (n=346), 19.7% (n=106), and 1.5% (n=8), respectively. Metastases to the liver and pleura predicted poor prognosis, although bone metastases predicted relatively good prognosis. The prognosis of single brain metastasis was relatively better than that of multiple brain metastases. Multi-factor analysis showed that the patient’s age, different metastatic organs, the numbers of metastatic organs, and different treatment were independent risk factors for survival.

Conclusion

The prognosis for patients with stage IV lung cancer is poor. Patient’s age, the type and number of metastatic organs, and method of treatment are the main factors affecting survival.

NKTR-102 Efficacy versus irinotecan in a mouse model of brain metastases of breast cancer

Background

Brain metastases are an increasing problem in women with invasive breast cancer. Strategies designed to treat brain metastases of breast cancer, particularly chemotherapeutics such as irinotecan, demonstrate limited efficacy. Conventional irinotecan distributes poorly to brain metastases; therefore, NKTR-102, a PEGylated irinotecan conjugate should enhance irinotecan and its active metabolite SN38 exposure in brain metastases leading to brain tumor cytotoxicity.

Methods

Female nude mice were intracranially or intracardially implanted with human brain seeking breast cancer cells (MDA-MB-231Br) and dosed with irinotecan or NKTR-102 to determine plasma and tumor pharmacokinetics of irinotecan and SN38. Tumor burden and survival were evaluated in mice treated with vehicle, irinotecan (50 mg/kg), or NKTR-102 low and high doses (10 mg/kg, 50 mg/kg respectively).

Results

NKTR-102 penetrates the blood-tumor barrier and distributes to brain metastases. NKTR-102 increased and prolonged SN38 exposure (>20 ng/g for 168 h) versus conventional irinotecan (>1 ng/g for 4 h). Treatment with NKTR-102 extended survival time (from 35 days to 74 days) and increased overall survival for NKTR-102 low dose (30 % mice) and NKTR-102 high dose (50 % mice). Tumor burden decreased (37 % with 10 mg/kg NKTR-102 and 96 % with 50 mg/kg) and lesion sizes decreased (33 % with 10 mg/kg NKTR-102 and 83 % with 50 mg/kg NKTR-102) compared to conventional irinotecan treated animals.

Conclusions

Elevated and prolonged tumor SN38 exposure after NKTR-102 administration appears responsible for increased survival in this model of breast cancer brain metastasis. Further, SN38 concentrations observed in this study are clinically achieved with 145 mg/m² NKTR-102, such as those used in the BEACON trial, underlining translational relevance of these results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1672-4) contains supplementary material, which is available to authorized users.

Involvement of epimutations in meningioma

Epimutations are heritable and reversible cell markers, which can influence cell function going beyond the effects of DNA mutations. They result from multiple and coordinated mechanisms able to modulate gene expression. Regarding the significance of epigenetics in meningioma, few and somehow contradictory results are available, although promising information has been obtained. Here we highlight the most recent advances about the impact of DNA methylation, histone modifications, and microRNA regulation on meningioma development as well as the interplay between genetic and epigenetic alterations. Data indicate that epigenetics can help to identify novel candidate genes for the management and treatment of meningioma.

Sunitinib tissue distribution changes after coadministration with ketoconazole in mice

Sunitinib is a multitargeted tyrosine kinase inhibitor approved for gastrointestinal stromal tumor (GIST), advanced renal cell carcinoma (RCC) and pancreatic neuroendocrine tumors. It is metabolized via CYP3A4 and has low brain penetration due to efflux transporters ABCB1B and ABCG2. We studied the interaction with ketoconazole (50 mg/kg), antifungal drug which shares metabolic pathways and efflux transporters, in ICR female mice after oral coadministration (30 min apart) of 60 mg/kg sunitinib (study group) versus sunitinib alone (control group). Plasma, liver, kidney and brain sunitinib concentrations were measured by HPLC at 2, 5, 10, 20, 40 min, 1, 2, 4, 6, 12 h post-sunitinib administration, and non-compartmental pharmacokinetic parameters estimated. In plasma, ketoconazole coadministration increased plasma maximum concentration (C MAX) 60 %, delayed time to C MAX (T MAX); 1.6-fold greater area under the curve AUC0→∞ (p < 0.001); lower apparent steady-state volume of distribution (V SS/F) and oral clearance (Cl/F) 40 and 61 %, respectively; and shorter elimination half-life (t 1/2). Sunitinib exhibited extensive tissue distribution which increased after ketoconazole coadministration: total area under the curve (AUC0→∞) increased 1.8-, 2.8- and 1.2-fold in kidney, liver and brain, respectively (all p < 0.001). Sunitinib presented high tissue-to-plasma AUC0→∞ ratio in liver (17.8 ± 1.2), kidney (14.6 ± 1.52) and brain (2.25 ± 0.18) which was modified after coadministration: AUC0→∞ ratio increased in liver (31.4 ± 4.7; p < 0.001), kidney (17.1 ± 2.2; p > 0.05) and decreased in brain (1.70 ± 0.23, p > 0.05). The results showed a significant ketoconazole-sunitinib interaction that affected plasma, tissue pharmacokinetics and tissue uptake mechanisms. The study portrays the risk to increase toxicity and potential clinical translatability to treat tumors in tissues.

In vivo delivery of miRNAs for cancer therapy: challenges and strategies

MicroRNAs (miRNAs), small non-coding RNAs, can regulate post-transcriptional gene expressions and silence a broad set of target genes. miRNAs, aberrantly expressed in cancer cells, play an important role in modulating gene expressions, thereby regulating downstream signaling pathways and affecting cancer formation and progression. Oncogenes or tumor suppressor genes regulated by miRNAs mediate cell cycle progression, metabolism, cell death, angiogenesis, metastasis and immunosuppression in cancer. Recently, miRNAs have emerged as therapeutic targets or tools and biomarkers for diagnosis and therapy monitoring in cancer. Since miRNAs can regulate multiple cancer-related genes simultaneously, using miRNAs as a therapeutic approach plays an important role in cancer therapy. However, one of the major challenges of miRNA-based cancer therapy is to achieve specific, efficient and safe systemic delivery of therapeutic miRNAs in vivo. This review discusses the key challenges to the development of the carriers for miRNA-based therapy and explores current strategies to systemically deliver miRNAs to cancer without induction of toxicity.

Epigenetic regulation of p14ARF and p16INK4A expression in cutaneous and uveal melanoma

Inactivation of p14ARF and p16INK4A by epigenetic changes in cutaneous and uveal melanoma has been here investigated. Compared with melanocytes, p14ARF mRNA reduction and p16INK4A inactivation were frequently noticed. No association between p14ARF promoter methylation and mRNA levels was found, whereas aberrant p16INK4A methylation was associated with gene silencing (p<0.001). Comparative analysis within melanomas of different Breslow's thicknesses showed that drastic reductions in p14ARF and p16INK4A expression appeared at the level of thin/intermediate and intermediate/thick transitions. The effects of 5-aza-2'-deoxycytidine (5-aza-dC) and suberanilohydroxamic acid (SAHA) on in vivo binding of DNA methyltransferases (DNMTs) and acetyl histone H3/H4 to p14ARF and p16INK4A promoters were tested together with the impact of ectopic expression of p14ARF and p16INK4A on cell proliferation, migration, and invasion. SAHA treatment induced H3 and H4 hyperacetylation at the p14ARF promoter followed by increased p14ARF expression, whereas exposure to 5-aza-dC decreased the recruitment of DNMT1 and DNMT3b at the p16INK4A promoter and reactivated p16INK4A. Studies on promoter-associated di-methyl histone H3 (Lys4) levels ruled out an involvement of this epigenetic trait on p14ARF and p16INK4A expression. The enforced expression of p14ARF or p16INK4A and, even more so, their co-expression, significantly reduced cell proliferation, migration and invasion. Our data pinpoint: i) a frequent impairment of p14ARF and p16INK4A gene expression by epigenetic modifications in melanoma; ii) histone hypoacetylation as the dominant mechanism of p14ARF silencing; and iii) 5' CpG promoter methylation as the major mechanism of p16INK4A gene inactivation. Collectively, our data suggest that selected epi-drugs may be useful in melanoma treatment.

In comparative analysis of multi-kinase inhibitors for targeted medulloblastoma therapy pazopanib exhibits promising in vitro and in vivo efficacy

Regardless of the recent advances in cytotoxic therapies, 30% of children diagnosed with medulloblastoma. succumb to the disease. Therefore, novel therapeutic approaches are warranted. Here we demonstrate that Pazopanib a clinically approved multi-kinase angiogenesis inhibitor (MKI) inhibits proliferation and apoptosis in medulloblastoma cell lines. Moreover, Pazopanib profoundly attenuates medulloblastoma cell migration, a prerequisite for tumor invasion and metastasis. In keeping with the observed anti-neoplastic activity of Pazopanib, we also delineate reduced phosphorylation of the STAT3 protein, a key regulator of medulloblastoma proliferation and cell survival. Finally, we document profound in vivo activity of Pazopanib in an orthotopic mouse model of the most aggressive c-myc amplified human medulloblastoma variant. Pazopanib reduced the growth rate of intracranial growing medulloblastoma and significantly prolonged the survival. Furthermore, to put these results into a broader perspective we analysed Pazopanib side by side with the MKI Sorafenib. Both compounds share a similar target profile but display different pharmacodynamics and pharmacokinetics with distinct cytotoxic activity in different tumor entities. Thus, we identified Pazopanib as a new promising candidate for a rational clinical assessment for targeted paediatric medulloblastoma therapy.

Phase I study of bendamustine with concurrent whole brain radiation therapy in patients with brain metastases from solid tumors

A phase I study was conducted to evaluate the dose-limiting toxicities (DLTs) and to determine the maximum tolerated dose (MTD)/recommended phase II dose of bendamustine with concurrent whole brain radiation (WBR) in patients with brain metastases (BM) from solid tumors. Four doses of intravenous weekly bendamustine were administered with 3 weeks of WBR at three dose levels (60, 80, and 100 mg/m(2)) according to a standard 3 + 3 phase I design. A total of 12 patients with solid tumor BM were enrolled in the study (six with non-small cell lung cancer, four with melanoma, one with breast cancer, and one with neuroendocrine carcinoma). The first two dose levels had three patients each, and the third dose level had six total patients. Plasma pharmacokinetic studies of bendamustine demonstrated no significant differences from pharmacokinetic characteristics of bendamustine in other studies. No DLTs were noted at any dose levels, and no grade 4 toxicities occurred. The MTD of weekly bendamustine with concurrent WBR was 100 mg/m(2). The majority of trial patients died from progressive systemic disease rather than their brain disease. The combination of weekly bendamustine with concurrent WBR was acceptably tolerated. The efficacy of this combination may be evaluated in a phase II trial with stratification by histologies.

Treatment of single or multiple brain metastases by hypofractionated stereotactic radiotherapy using helical tomotherapy

This study investigated the clinical outcomes of a 4-fraction stereotactic radiotherapy (SRT) study using helical tomotherapy for brain metastases. Between August 2009 and June 2013, 54 patients with a total of 128 brain metastases underwent SRT using tomotherapy. A total dose of 28 or 28.8 Gy at 80% isodose was administered in 4 fractions for all tumors. The mean gross tumor volume (GTV) was 1.9 cc. Local control (LC) rates at 6, 12, and 18 months were 96%, 91%, and 88%, respectively. The 12-month LC rates for tumors with GTV ≤0.25, >0.25 and ≤1, and >1 cc were 98%, 82%, and 93%, respectively; the rates were 92% for tumors >3 cc and 100% for >10 cc. The 6-month rates for freedom from distant brain failure were 57%, 71%, and 55% for patients with 1, 2, and >3 brain metastases, respectively. No differences were significant. No major complications were observed. The 4-fraction SRT protocol provided excellent tumor control with minimal toxicity. Distant brain failure was not so frequent, even in patients with multiple tumors. The results of the current study warrant a prospective randomized study comparing single-fraction stereotactic radiosurgery (SRS) with SRT in this patient population.

Phase 1 trial of dichloroacetate (DCA) in adults with recurrent malignant brain tumors

BACKGROUND

Recurrent malignant brain tumors (RMBTs) carry a poor prognosis. Dichloroacetate (DCA) activates mitochondrial oxidative metabolism and has shown activity against several human cancers.

DESIGN

We conducted an open-label study of oral DCA in 15 adults with recurrent WHO grade III - IV gliomas or metastases from a primary cancer outside the central nervous system. The primary objective was detection of a dose limiting toxicity for RMBTs at 4 weeks of treatment, defined as any grade 4 or 5 toxicity, or grade 3 toxicity directly attributable to DCA, based on the National Cancer Institute's Common Toxicity Criteria for Adverse Events, version 4.0. Secondary objectives involved safety, tolerability and hypothesis-generating data on disease status. Dosing was based on haplotype variation in glutathione transferase zeta 1/maleylacetoacetate isomerase (GSTZ1/MAAI), which participates in DCA and tyrosine catabolism.

RESULTS

Eight patients completed at least 1 four week cycle. During this time, no dose-limiting toxicities occurred. No patient withdrew because of lack of tolerance to DCA, although 2 subjects experienced grade 0-1 distal parasthesias that led to elective withdrawal and/or dose-adjustment. All subjects completing at least 1 four week cycle remained clinically stable during this time and remained on DCA for an average of 75.5 days (range 26-312).

CONCLUSIONS

Chronic, oral DCA is feasible and well-tolerated in patients with recurrent malignant gliomas and other tumors metastatic to the brain using the dose range established for metabolic diseases. The importance of genetic-based dosing is confirmed and should be incorporated into future trials of chronic DCA administration.

Extremely delayed brain metastasis from renal cell carcinoma

Brain metastasis occurs in 3.9-24% of patients with renal cell carcinoma (RCC), with an average interval from nephrectomy to brain metastasis of 1 to 3 years. A few cases have been reported where brain metastasis occurred after a delay of more than 10 years from the initial onset of renal cell carcinoma. This long interval for central nervous system metastasis from the primary cancer has been recognized as an indicator of better prognosis. Histopathological confirmation and aggressive treatment must be considered in these delayed brain metastases cases, since the patients usually show long survival and good prognosis. We present a case of a 76-year-old woman who developed extremely late multiple brain metastases 18 years after a nephrectomy for RCC.

The efficacy and limitations of stereotactic radiosurgery as a salvage treatment after failed whole brain radiotherapy for brain metastases

The aim of the present study was to evaluate the efficacy and limitations of repeat stereotactic radiosurgery (SRS) salvage for patients with recurrence of brain metastases (BM) after whole brain radiotherapy (WBRT). This is a retrospective, observational, single-center trial analyzing 77 consecutive patients with recurrent BM who were treated primarily with WBRT. All patients underwent SRS as salvage treatment. Median age was 62 years, and median Karnofsky performance status (KPS) was 80. The median interval between the starting date of WBRT and radiosurgery was 10.6 months. One, two and more than two SRS sessions were required in 42, 13 and 22 patients, respectively. The median total planning target volume (PTV) was 8.1 mL and the median dose prescribed was 20 Gy. The median follow-up was 7.7 months. 1- and 2-year neurological death-free survival (NS) rates were 87 and 78 %, respectively. Competing risk analysis demonstrated active extra-central nervous system (CNS) disease [Hazard ratio (HR) 0.236, P = 0.041] and total PTV on initial SRS (≥ 5 mL) (HR 4.22, P = 0.033) to be associated with the NS rate. 1- and 2-year overall survival (OS) rates were 41 and 11 %, respectively. The median OS time was 8.2 months. Active extra-CNS disease (HR 1.94, P = 0.034) and high KPS (≥ 90) (HR 0.409, P = 0.006) were associated with the OS rate. In total, 798 tumors (75 %) in 66 patients (86 %) with sufficient radiological follow-up data were evaluated. 1- and 2-year metastasis local control rates were 76.6 and 57.9 %, respectively. Prescribed dose (≥ 20 Gy) (HR 0.326, P < 0.001), tumor volume (≥ 2 mL) (HR 1.98, P = 0.007) and metastases from breast cancer (HR 0.435, P < 0.001) were independent predictive factors for local tumor control. Repeat salvage SRS for recurrent BM after WBRT appeared to be a safe and effective treatment. In the majority of patients, even those with numerous BM, neurological death could be delayed or even prevented.