Management of brain metastases in patients with melanoma

Diagnostic challenge: primary leptomeningeal melanoma with melanomatosis, illustrative case report

Primary leptomeningeal melanoma is an extremely rare type of intracranial melanoma. It cannot be reliably distinguished from metastatic melanoma on neuroimaging and histopathological characteristics alone; its diagnosis is established only after exclusion of secondary metastatic disease from a cutaneous, mucosal or retinal primary. Prognosis is poor, partly due to its high rate of misdiagnosis. Herein, we report a case of a primary meningeal melanoma of the skull base with melanomatosis, in a 31-year-old man, mimicking meningioma. Our aim is to highlight the diagnostic pitfalls and to discuss the histopathological differential diagnoses, especially with other pigmented lesions of central nervous system.

Breast cancer metastasis to brain results in recruitment and activation of microglia through annexin-A1/formyl peptide receptor signaling

Background

Despite advancements in therapies, brain metastasis in patients with triple negative subtype of breast cancer remains a therapeutic challenge. Activated microglia are often observed in close proximity to, or within, malignant tumor masses, suggesting a critical role that microglia play in brain tumor progression. Annexin-A1 (ANXA1), a glucocorticoid-regulated protein with immune-regulatory properties, has been implicated in the growth and metastasis of many cancers. Its role in breast cancer-microglia signaling crosstalk is not known.

Methods

The importance of microglia proliferation and activation in breast cancer to brain metastasis was evaluated in MMTV-Wnt1 spontaneous mammary tumor mice and BALBc mice injected with 4T1 murine breast cancer cells into the carotid artery using flow cytometry. 4T1 induced-proliferation and migration of primary microglia and BV2 microglia cells were evaluated using 2D and coculture transwell assays. The requirement of ANXA1 in these functions was examined using a Crispr/Cas9 deletion mutant of ANXA1 in 4T1 breast cancer cells as well as BV2 microglia. Small molecule inhibition of the ANXA1 receptor FPR1 and FPR2 were also examined. The signaling pathways involved in these interactions were assessed using western blotting. The association between lymph node positive recurrence-free patient survival and distant metastasis-free patient survival and ANXA1 and FPR1 and FPR2 expression was examined using TCGA datasets.

Results

Microglia activation is observed prior to brain metastasis in MMTV-Wnt1 mice with primary and secondary metastasis in the periphery. Metastatic 4T1 mammary cancer cells secrete ANXA1 to promote microglial migration, which in turn, enhances tumor cell migration. Silencing of ANXA1 in 4T1 cells by Crispr/Cas9 deletion, or using inhibitors of FPR1 or FPR2 inhibits microglia migration and leads to reduced activation of STAT3. Finally, elevated ANXA1, FPR1 and FPR2 is significantly associated with poor outcome in lymph node positive patients, particularly, for distant metastasis free patient survival.

Conclusions

The present study uncovered a network encompassing autocrine/paracrine ANXA1 signaling between metastatic mammary cancer cells and microglia that drives microglial recruitment and activation. Inhibition of ANXA1 and/or its receptor may be therapeutically rewarding in the treatment of breast cancer and secondary metastasis to the brain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01514-2.

Seizures in cancer patients: a vast spectrum of etiologies

Aim: This study aims to recognize the distribution of different seizures etiologies in cancer patients, the most common primary tumors responsible for brain metastases, the most epileptogenic primary tumors and the therapeutic modalities. Methods: A retrospective study was conducted at Hotel-Dieu de France Hospital targeting patients admitted to hematology–oncology department between 2005 and 2016 who presented a seizure. Results: Of the 153 included patients, mean age was 57 years (standard deviation = 16 years) and a male predominance (66%). The majority of seizures were due to a primary tumor (49%) or brain metastases (32%). Other reversible (metabolic and drug) or nonreversible causes (carcinomatous meningitis, radiation and cardiovascular complications) formed the remaining causes. Regarding antiepileptic treatments, sodium valproate was mostly used, followed by levetiracetam and phenytoin. Conclusion: Numerous reversible causes are involved in the onset of epileptic seizures, including metabolic disorders, antibiotics and chemotherapies.

Comparison of prognostic indices in patients who undergo melanoma brain metastasis radiosurgery

OBJECTIVE The goal of this study was to use 4 prognostic indices to compare survival times of patients who underwent Gamma Knife stereotactic radiosurgery (SRS) to treat melanoma brain metastases. METHODS The authors analyzed 422 consecutive patients (1440 brain metastases) who underwent Gamma Knife SRS. The median total brain tumor volume was 4.7 cm³ (range 0.3-69.3 cm³), and the median number of metastases was 2 (range 1-32). One hundred thirty-two patients underwent whole-brain radiation therapy. Survival times were compared using recursive partitioning analysis (RPA), the Score Index for Radiosurgery (SIR), the Basic Score for Brain Metastases (BSBM), and the Diagnosis-Specific Graded Prognostic Assessment (DS-GPA). RESULTS The overall survival times after SRS were compared. With the RPA index, survival times were 2.6 months (Class III, n = 27), 5.5 months (Class II, n = 348), and 13.0 months (Class I, n = 47). With the DS-GPA index, survival times were 2.8 months (Scores 0-1, n = 67), 4.2 months (Scores 1.5-2.0, n = 143), 6.6 months (Scores 2.5-3.0, n = 111), and 9.4 months (Scores 3.5-4.0, n = 101). With the SIR, survival times were 3.2 months (Scores 0-3, n = 56), 5.8 months (Scores 4-7, n = 319), and 12.7 months (Scores 8-10, n = 47). With the BSBM index, survival times were 2.6 months (BSBM0, n = 47), 5.4 months (BSBM1, n = 282), 11.0 months (BSBM2, n = 86), and 8.8 months (BSBM3, n = 7). The DS-GPA index was the most balanced by case numbers in each class and provided the overall best prognostic index for overall survival. CONCLUSIONS The DS-GPA index proved most balanced and predictive of survival for patients with melanoma who underwent SRS as part of management for brain metastases. Patients whose DS-GPA score was ≥ 2.5 had predictably improved survival times after SRS.

Ipilimumab and craniotomy in patients with melanoma and brain metastases: a case series

OBJECT In patients with large or symptomatic brain lesions from metastatic melanoma, the value of resection of metastases to facilitate administration of systemic ipilimumab therapy has not yet been described. The authors undertook this study to investigate whether craniotomy creates the opportunity for patients to receive and benefit from ipilimumab who would otherwise succumb to brain metastasis prior to the onset of regression. METHODS All patients with metastatic melanoma who received ipilimumab and underwent craniotomy for metastasis resection between 2008 and 2014 at the Massachusetts General Hospital were identified through retrospective chart review. The final analysis included cases involving patients who underwent craniotomy within 3 months prior to initiation of therapy or up to 6 months after cessation of ipilimumab administration. RESULTS Twelve patients met the inclusion criteria based on timing of therapy (median age 59.2). The median number of metastases at the time of craniotomy was 2. The median number of ipilimumab doses received was 4. Eleven of 12 courses of ipilimumab were stopped for disease progression, and 1 was stopped for treatment-induced colitis. Eight of 12 patients had improvement in their performance status following craniotomy. Of the 6 patients requiring corticosteroids prior to craniotomy, 3 tolerated corticosteroid dose reduction after surgery. Ten of 12 patients had died by the time of data collection, with 1 patient lost to follow-up. The median survival after the start of ipilimumab treatment was 7 months. CONCLUSIONS In this series, patients who underwent resection of brain metastases in temporal proximity to receiving ipilimumab had qualitatively improved performance status following surgery in most cases. Surgery facilitated corticosteroid reduction in select patients. Larger analyses are required to better understand possible synergies between craniotomy for melanoma metastases and ipilimumab treatment.

Long-term outcomes of helper peptide vaccination for metastatic melanoma

OBJECTIVE

The objective of this study was to compare the long-term outcome of patients with metastatic melanoma vaccinated with 6MHP to that of a group of unvaccinated historical controls.

BACKGROUND

A multipeptide vaccine (6MHP), designed to induce helper T cells against melanocytic and cancer-testis antigens, has been shown to induce specific Th1-dominant CD4+ T cell responses.

METHODS

The 6MHP vaccine was administered to patients with metastatic melanoma. Circulating CD4+ T cell responses were measured by proliferation or direct IFN-gamma ELIspot assay. Overall survival of vaccinated patients was compared to a group of clinically comparable historical controls using multivariable Cox regression analysis and Kaplan-Meier survival analysis, taking into account age, metastatic site, and resection status.

RESULTS

Across 40 vaccinated patients and 87 controls, resection status (HR 0.54, P = 0.004) and vaccination (HR 0.24, P < 0.001) were associated with improved overall survival. Forty pairs of vaccinated patients and controls were matched by metastatic site, resection status, and age within 10 years. Median survival was significantly longer for vaccinated patients (5.4 vs 1.3 years, P < 0.001). Among the vaccinated patients, the development of a specific immune response after vaccination was associated with improved survival (HR 0.35, P = 0.040).

CONCLUSIONS

Helper peptide vaccination is associated with improved overall survival among patients with metastatic melanoma. These data support a randomized prospective trial of the 6MHP vaccine.

Intracranial malignant melanoma: A report of 7 cases

The aim of the present study was to investigate the clinical diagnosis and treatment of intracranial malignant melanoma. For this purpose, the clinical manifestation, signs, cerebrospinal fluid (CSF) contents, imageology, pathological features, treatment and prognosis of 7 cases of intracranial malignant melanoma were analyzed in The Chinese PLA General Hospital (Beijing, China) from 1996 to 2013. All the melanoma cases were confirmed by histopathology, and CSF cytopathology demonstrated that there were 5 cases of primary malignant melanoma and 2 cases of secondary malignant melanoma. Among the patients, 4 presented with >1 pigmented nevus in the skin, and 1 presented with skin melanoma. Intracranial malignant melanoma mostly affects middle-aged males. CSF cytopathology and imageology (particularly enhanced magnetic resonance), are important tools in the diagnosis of the disease. Particularly, when a patient presents with a pigmented nevus in the skin and an abnormal lesion in the brain, a diagnosis of intracranial malignant melanoma should be considered.

The current management of brain metastasis in melanoma: a focus on riluzole

Brain metastasis is a common endpoint in human malignant melanoma, and the prognosis for patients remains poor despite advancements in therapy. Current treatment for melanoma metastatic to the brain is grouped into those providing symptomatic relief such as corticosteroids and antiepileptic agents, to those that are disease modifying. Related to the latter group, recent studies have demonstrated that aberrant glutamate signaling plays a role in the transformation and maintenance of various cancer types, including melanoma. Glutamate secretion from these and surrounding cells have been found to stimulate regulatory pathways that control tumor growth, proliferation and survival in vitro and in vivo. The antiglutamatergic actions of an inhibitor of glutamate release, riluzole, have been detected by its ability to clear glutamate from the synapse, and it has been shown to inhibit glutamate release rather than directly inhibiting glutamate receptors. Preclinical studies have demonstrated the ability of riluzole to act as a radiosensitizing agent in melanoma. The effect of riluzole on downstream glutamatergic signaling has pointed to cross talk between the metabotropic G-protein-coupled glutamate receptors implicated in a subset of human melanomas with other signaling pathways, including apoptotic, angiogenic, ROS and cell invasion mechanisms, thus establishing its potential to be further explored in combination therapy regimens for both primary human melanoma and melanoma metastatic to the brain.

Stereotactic radiotherapy of orbital metastasis from malignant melanoma: a case study

Objective:

Orbital metastases lead to many distressful symptoms.

Methods:

A case-report of a 44-year-old woman with a melanoma metastasis in the orbital cavity, is reported. A patient presented with headache, proptosis and diplopia. The stereotactic radiotherapy of 19.5 Gy in three fractions using CyberKnife was performed. Follow-up examination 7 months later revealed satisfactory local control of the tumour, alleviation of orbital symptoms with no negative impact on visual function.

Conclusion:

Stereotactic radiotherapy seems to be a safe and effective treatment of orbital metastases from melanoma.

Roles for endothelin receptor B and BCL2A1 in spontaneous CNS metastasis of melanoma

Metastatic spread of melanoma to the central nervous system (CNS) is a common and devastating manifestation of disease progression, which, despite its clinical importance, remains poorly understood with respect to underlying molecular mechanisms. Using a recently developed preclinical model of spontaneous melanoma CNS metastasis, we have identified alterations in expression of endothelin receptor B (EDNRB) as a potential factor that influences brain metastatic potential. Induced overexpression of this gene mediated enhanced overall metastatic disease, and resulted in an increased incidence of spontaneous CNS metastases. In contrast, the overexpression of other highlighted genes, such as BCL2A1, did not affect the incidence of CNS metastases but nevertheless appears to facilitate intracranial tumor growth. The prometastatic effect in the CNS associated with EDNRB appears to be mediated by the interaction with its ligands resulting in enhanced tumor cell proliferation and thus intracranial melanoma growth. That EDNRB contributes to melanoma metastasis is underscored by the fact that its therapeutic inhibition by the EDNRB-specific inhibitor A192621 translated into improved outcomes when treating mice with either visceral metastases or intracranial tumors. The identification of an influential role of EDNRB in CNS melanoma spontaneous metastasis may provide both a target for therapeutic intervention as well as a potential prognostic marker for patients having an increased predisposition for incidence of CNS melanoma metastases.

Cerebral melanoma metastases: a critical review on diagnostic methods and therapeutic options

Malignant melanoma represents the third most common cause for cerebral metastases after breast and lung cancer. Central nervous system (CNS) metastases occur in 10 to 40% of patients with melanoma. Most of the symptoms of CNS melanoma metastases are unspecific and depend on localization of the lesion. All patients with new neurological signs and a previous primary melanoma lesion must be investigated. Although primary diagnosis may rely on computed tomography scan, magnetic resonance images are usually used in order to study more precisely the characteristics of the lesions in and to embase the surgical plan. Other possible complementary exams are: positron emission tomography, iofetamine cintilography, immunohistochemistry of liquor, monoclonal antibody immunocytology, optical coherence tomography, and transcriptase-polymerase chain reaction. Treatment procedures are indicated based on patient clinical status, presence of unique or multiple lesions, and family agreement. Often surgery, radiosurgery, whole brain radiotherapy, and chemotherapy are combined in order to obtain longer remissions and optimal symptom relieve. Corticoids may be also useful in those cases that present with remarkable peritumoral edema and important mass effect. Despite of the advance in therapeutic options, prognosis for patients with melanoma brain metastases remains poor with a median survival time of six months after diagnosis.

Preclinical approaches to study the biology and treatment of brain metastases

Metastatic spread to the central nervous system (CNS) is a common and devastating manifestation of major cancer types. Its incidence is associated with poor prognosis manifested by neurological deterioration leading to diminished quality of life and an extremely short median survival. CNS metastasis is becoming an increasingly important clinical problem. This is especially the case for certain types of cancers for which effective treatments of visceral disease are available. As a result of the present limitations in treating CNS metastases, this manifestation of tumor progression remains an unmet clinical need. Despite its significance, our general understanding of the mechanisms that regulate the brain-metastatic phenotype is currently meager. Both the analysis of mechanistic aspects of brain metastasis and the development of effective treatments necessitate the use of appropriate in vivo models that recapitulate the interaction of the tumor cells with the microenvironment of the brain. Here we review the available preclinical models of CNS metastasis and their use as tools to advance knowledge of the biology of the disease (with the aim of identifying relevant molecular determinants, prognostic biomarkers, and therapeutic targets) as well as examining effective approaches for treatment.

Growth of melanoma brain tumors monitored by photoacoustic microscopy

Melanoma is a primary malignancy that is known to metastasize to the brain and often causes death. The ability to image the growth of brain melanoma in vivo can provide new insights into its evolution and response to therapies. In our study, we use a reflection mode photoacoustic microscopy (PAM) system to detect the growth of melanoma brain tumor in a small animal model. The melanoma tumor cells are implanted in the brain of a mouse at the beginning of the test. Then, PAM is used to scan the region of implantation in the mouse brain, and the growth of the melanoma is monitored until the death of the animal. It is demonstrated that PAM is capable of detecting and monitoring the brain melanoma growth noninvasively in vivo.

Outcome predictors of Gamma Knife surgery for melanoma brain metastases. Clinical article

OBJECT

To evaluate the role of stereotactic radiosurgery (SRS) in the management of brain metastases from melanoma, the authors assessed clinical outcomes and prognostic factors for survival and tumor control.

METHODS

The authors reviewed 333 consecutive patients with melanoma who underwent SRS for 1570 brain metastases from cutaneous and mucosal/acral melanoma. The patient population consisted of 109 female and 224 male patients with a median age of 53 years. Two hundred eleven patients (63%) had multiple metastases. One hundred eighteen patients (35%) underwent whole-brain radiation therapy (WBRT). The target volume ranged from 0.1 cm(3) to 37.2 cm(3). The median marginal dose was 18 Gy.

RESULTS

Actuarial survival rates were 70% at 3 months, 47% at 6 months, 25% at 12 months, and 10% at 24 months after radiosurgery. Factors associated with longer survival included controlled extracranial disease, better Karnofsky Performance Scale score, fewer brain metastases, no prior WBRT, no prior chemotherapy, administration of immunotherapy, and no intratumoral hemorrhage before radiosurgery. The median survival for patients with a solitary brain metastasis, controlled extracranial disease, and administration of immunotherapy after radiosurgery was 22 months. Sustained local tumor control was achieved in 73% of the patients. Sixty-four (25%) of 259 patients who had follow-up imaging after SRS had evidence of delayed intratumoral hemorrhage. Sixteen patients underwent a craniotomy due to intratumoral hemorrhage. Seventeen patients (6%) had asymptomatic and 21 patients (7%) had symptomatic radiation effects. Patients with ≤ 8 brain metastases, no prior WBRT, and the recursive partitioning analysis Class I had extended survivals (median 54.3 months).

CONCLUSIONS

Stereotactic radiosurgery is an especially valuable option for patients with controlled systemic disease even if they have multiple metastatic brain tumors.

Surgical treatment of advanced melanoma

Primary surgical treatment should be considered for patients with metastatic melanoma. Because of the poor response of melanoma to chemotherapy or radiation therapy, surgery can be the best approach to quickly eliminate detectable disease and return the patient to normal activities. In properly selected patients, surgery can lead to significant palliation and prolongation of survival. This article reviews the principles of patient selection and the potential benefits of surgical management of melanoma metastatic to various sites. Novel adjuvant therapies are being developed to augment the benefits of surgical treatment of advanced melanoma in the future.

Surgery and radiotherapy in the treatment of cutaneous melanoma

Adequate surgical management of primary melanoma and regional lymph node metastasis, and rarely distant metastasis, is the only established curative treatment. Surgical management of primary melanomas consists of excisions with 1–2 cm margins and primary closure. The recommended method of biopsy is excisional biopsy with a 2 mm margin and a small amount of subcutaneous fat. In specific situations (very large lesions or certain anatomical areas), full-thickness incisional or punch biopsy may be acceptable. Sentinel lymph node biopsy provides accurate staging information for patients with clinically unaffected regional nodes and without distant metastases, although survival benefit has not been proved. In cases of positive sentinel node biopsy or clinically detected regional nodal metastases (palpable, positive cytology or histopathology), radical removal of lymph nodes of the involved basin is indicated. For resectable local/in-transit recurrences, excision with a clear margin is recommended. For numerous or unresectable in-transit metastases of the extremities, isolated limb perfusion or infusion with melphalan should be considered. Decisions about surgery of distant metastases should be based on individual circumstances. Radiotherapy is indicated as a treatment option in select patients with lentigo maligna melanoma and as an adjuvant in select patients with regional metastatic disease. Radiotherapy is also indicated for palliation, especially in bone and brain metastases.

Factors affecting the outcome after treatment for metastatic melanoma to the brain

BACKGROUND

Because of the difficulties inherent to the treatment of metastatic melanoma to the brain including high rates of disease progression and local treatment failure, we attempted to determine the prognostic factors that impacted the outcome of these patients, and reviewed patient outcome based on primary treatment with either surgical resection or SRS.

METHODS

A retrospective review identified 37 patients treated for metastatic melanoma between July 2002 and April 2007. Information was obtained documenting systemic disease, preoperative symptoms, tumor size and location, disease recurrence, primary and secondary treatments, and survival time.

RESULTS

Two patients were alive as of March 2008. The median survival time for patients primarily treated with surgical resection was 9.7 months compared to 7.9 months for patients initially treated with SRS. Solitary brain metastases and the absence of both preoperative hemorrhage and lung metastases served as prognostic factors increasing survival in both groups. Four patients undergoing primary treatment with SRS required subsequent surgical intervention secondary to radiation necrosis (3 patients) or local recurrence (1 patient). All 4 had lesions greater than 1.5 cm. For surgical patients, planned postoperative treatment with either radiosurgery or radiation therapy increased survival time to 12.3 months vs 7.3 months.

CONCLUSIONS

Patients with positive prognostic factors including solitary brain lesions, absence of hemorrhage preoperatively, and absence of lung disease are viable candidates for aggressive, surgical intervention followed by adjuvant therapy with radiosurgery or conventional radiation therapy. Other patients should be considered for more conservative treatment with radiosurgery or other palliative treatments.

Multiple intracranial melanoma metastases: case report and review of the literature

Although intracerebral metastases of malignant melanoma are common, those located in the sellar region and within the pontocerebellar area are extremely rare. Furthermore, to our knowledge, there is no report about melanoma metastasis to the epiphysis published so far. We report here a 46-year-old patient who had metastatic lesions in the sellar region, cerebellopontine area and epiphysial gland, preceded by a primary melanoma at her left shoulder. The diagnosis of sellar metastasis was confirmed histopathologically following a stereotactic biopsy. The patient received whole-brain irradiation therapy combined with chemotherapy. After 10 months, she died from a severe hemorrhage in the cerebellopontine angle. Autopsy findings confirmed melanoma metastases both in the cerebellopontine angle and additionally in the epiphysial gland. To our knowledge, this is the first case of multiple intracranial melanoma metastases including the suprasellar region, the pontocerebellar and epiphysial area.

Gamma Knife surgery for the treatment of melanoma metastases: the effect of intratumoral hemorrhage on survival

OBJECT

Gamma Knife surgery (GKS) improves overall survival in patients with malignant melanoma metastatic to the brain. In this study the authors investigated which patient- or treatment-specific factors influence survival of patients with melanoma brain metastases; they pay particular interest to pre- and post-GKS hemorrhage.

METHODS

Demographic, treatment, and survival data on 59 patients with a total of 208 intracranial metastases who underwent GKS between 1998 and 2007 were abstracted from treatment records and from the Connecticut Tumor Registry. Multivariate analysis was used to identify factors that independently affected survival.

RESULTS

Survival was significantly better in patients with solitary metastasis (p = 0.04), lesions without evidence of pre-GKS hemorrhage (p = 0.004), and in patients with total tumor volume treated < 4 cm(3) (p = 0.02). Intratumoral bleeding occurred in 23.7% of patients pre-GKS. Intratumoral bleeding occurred at a mean of 1.8 months post-GKS at a rate of 15.2%. Unlike the marked effect of pretreatment bleeding, posttreatment bleeding did not independently affect survival. Sex, systemic control, race, metastases location, whole-brain radiation therapy, chemotherapy, history of antithrombotic medications, and cranial surgery had no independent association with survival.

CONCLUSIONS

These data corroborate previous findings that tumor burden (either as increased number or total volume of lesions) at the time of GKS is associated with diminished patient survival in those with intracerebral melanoma metastases. Patients who were noted to have hemorrhagic melanoma metastases prior to GKS appear to have a worse prognosis following GKS compared with patients with nonhemorrhagic metastases, despite similar rates of bleeding pre- and post-GKS treatment. Gamma Knife surgery itself does not appear to increase the rate of hemorrhage.

A cystic amelanotic melanoma metastasis to the brain: case report

As far as we know, cyst formation in intracranial melanoma is rare, and only 15 cases of intracranial amelanotic melanoma have been reported until now. A yellowish mass was observed in the frontal lobe. The content of the cyst consisted of old hematoma, xanthochromic fluid and necrotic tissue, was evacuated and the cyst wall was totally resected. No abnormal pigmentation was noted in the cyst wall and surrounding brain tissue. The imaging features of metastatic melanomas are distinctive due to the presence of melanin and the propensity for hemorrhage. Both hemorrhage and melanin can produce T1-weighted hyperintensity and T2-weighted signal intensity loss.

Development of a preclinical model of spontaneous human melanoma central nervous system metastasis

Metastatic spread of melanoma to the central nervous system (CNS) is associated with dismal prognosis. Preclinical testing of novel therapeutic approaches would be aided by the development of appropriate models of spontaneous CNS metastasis arising from primary tumors. A highly metastatic variant of the WM239A human melanoma cell line, designated 113/6-4L, was generated and used to test the efficacy of long-term, low-dose metronomic cyclophosphamide and vinblastine chemotherapy on advanced established metastatic disease in sites such as liver, lungs, and lymph node. This treatment resulted in control of advanced, systemic disease and prolongation of survival. Among long-term surviving mice, 20% showed the presence of spontaneous brain metastases. Two cell lines (131/4-5B1 and 131/4-5B2) were generated from such metastases, which were found to spontaneously metastasize to brain parenchyma with occasional localization to leptomeninges, after orthotopic transplantation and removal of the primary tumor. The cell lines were found to have increased ability to proliferate in brain-conditioned medium and displayed enhanced adhesion to lung and brain endothelial cells. These findings represent the first report of spontaneous CNS metastases generated from primary tumors of any human cancer in mice, which heritably maintains this phenotype, and as such, the variant cell lines generated should aid studies in the biology and treatment of CNS metastases, especially of melanoma origin.

A phase II study of thalidomide and temozolomide in patients with brain metastases from malignant melanoma: lymphopenia correlates with response

Background:

Central nervous system (CNS) metastases develop in nearly half of patients with advanced melanoma and in 15–20% CNS is the first site of relapse. Median overall survival is short, ranging from two to four months, and one-year survival rate is only 10–15%. THA has been shown to have both anti-angiogenetic and immuno-modulating effects. TMZ is an oral alkylating agent with an excellent oral bioavailability and it is highly lipophillic with an ability to penetrate the blood–brain barrier. TMZ and THA in combination were tested in patients with brain metastases from malignant melanoma.

Methods:

Between June 2004 and February 2007 patients with measurable metastatic melanoma in progression and PS ≤ 1 received TMZ in a dose of 150 mg/m² qd for seven days, followed by seven days off therapy and THA in 200 mg qd, both orally administered. Concomitant treatment with steroids was allowed. PBMCs were collected from the last 14 consecutive patients for evaluation of immune parameters.

Results:

Forty screened patients were eligible and evaluable for response, and 39 were evaluable for toxicity. 25 patients had asymptomatic and 15 symptomatic brain metastases. The toxicity was primarily grade 1–2 with no grade 4 or treatment-related deaths. Four patients had thromboembolic events grade 3. One patient obtained a CR and five a PR in the CNS, while two had CR and four had PR outside CNS. Overall response rate was 17.5%. We found a significant positive correlation between lymphopenia and objective response.

Conclusions:

The combination treatment was well tolerated but with more frequent thromboembolic events compared to single drug TMZ or THA. The treatment demonstrated activity in CNS as well as outside CNS. The correlation between lymphopenia and objective response needs further investigation.

A rational surgical approach to the treatment of distant melanoma metastases

The optimal treatment of melanoma involves multidisciplinary care. To many, this means surgical resection of early, localized disease and treatment of metastatic disease with chemotherapy, immunotherapy, or radiation. Because it is effective, results in little morbidity and may be repeated, surgery should have a central role in the treatment of selected patients with American Joint Committee on Cancer (AJCC) stage IV melanoma.

GAMMA KNIFE RADIOSURGERY IN THE MANAGEMENT OF MALIGNANT MELANOMA BRAIN METASTASES

OBJECTIVE

Radiosurgery is increasingly used to manage malignant melanoma brain metastases. We reviewed our series of patients who underwent radiosurgery for melanoma brain metastases to assess clinical outcomes and identify prognostic factors for survival and cerebral disease control.

METHODS

Two hundred forty-four patients had radiosurgery for the management of 754 metastatic tumors. A mean of 2.6 tumors were irradiated per procedure. The median tumor volume was 4.4 cm3. The median margin and maximum doses used were 18 and 32 Gy, respectively.

RESULTS

The median survival was 5.3 months after radiosurgery (mean, 10 mo; range, 0.2–114.3 mo). Patients survived a median of 7.8 months (mean, 13.4 mo) from the diagnosis of brain metastases and 44.9 months (mean, 69 mo) after the diagnosis of the primary tumor. Survival was better in patients with controlled systemic disease (12.7 mo), single brain metastasis (6.8 mo), and a Karnofsky performance score of 90 or 100% (6.3 mo). Sustained local control was achieved in 86.2% of tumors. Increased tumor volume and previous evidence of hemorrhage increased the risk of local failure. Multiple lesions and failure to provide systemic immunotherapy were predictors for the occurrence of new brain metastases, which developed in 41.7% of the patients. Symptomatic radiation changes occurred in 6.6% of the patients. Overall, 71.4% of the patients improved or remained clinically stable. Brain disease was the cause of death in 40.5% of the patients, usually from the development of new metastases.

CONCLUSION

Gamma knife radiosurgery for malignant melanoma brain metastases is safe and effective and provides a high rate of durable local control. Improved survival can be achieved in patients with single metastasis, controlled systemic disease, and a high Karnofsky performance score.

NK and CD4 Cells Collaborate to Protect against Melanoma Tumor Formation in the Brain

NK cells represent a potent immune effector cell type that have the ability to recognize and lyse tumors. However, the existence and function of NK cells in the traditionally "immune-privileged" CNS is controversial. Furthermore, the cellular interactions involved in NK cell anti-CNS tumor immunity are even less well understood. We administered non-Ag-loaded, immature dendritic cells (DC) to CD8alpha knockout (KO) mice and studied their anti-CNS tumor immune responses. DC administration induced dramatic antitumor immune protection in CD8alpha KO mice that were challenged with B16 melanoma both s.c. and in the brain. The CNS antitumor immunity was dependent on both CD4+ T cells and NK cells. Administration of non-Ag-loaded, immature DC resulted in significant CD4+ T cell and NK cell expansion in the draining lymph nodes at 6 days postvaccination, which persisted for 2 wk. Finally, DC administration in CD8alpha KO mice was associated with robust infiltration of CD4+ T cells and NK cells into the brain tumor parenchyma. These results represent the first demonstration of a potent innate antitumor immune response against CNS tumors in the absence of toxicity. Thus, non-Ag-loaded, immature DC administration, in the setting of CD8 genetically deficient mice, can induce dramatic antitumor immune responses within the CNS that surpass the effects observed in wild-type mice. Our results suggest that a better understanding of the cross-talk between DC and innate immune cells may provide improved methods to vaccinate patients with tumors located both systemically and within the CNS.

The role of surgery in treatment of stage IV melanoma

The prognosis for patients with melanoma has not improved over the last 30 years. So far, almost without exception, clinical trials conducted with single or multiple agent chemotherapy, biological therapy (interferon-alpha, interleukin-2), and biochemotherapy have failed to demonstrate consistent survival benefit. Without effective alternate treatments, surgery must be considered the primary treatment of melanoma, independent of disease stage. Although surgery is clearly favored as the treatment of localized melanoma, consensus opinion and clinician preference become divided once melanoma progresses beyond its primary site. Many physicians will adopt an attitude of resignation and hesitancy when treating metastatic melanoma. As a result, patients with advanced disease are often treated with medications that produce little survival or palliative benefit at the expense of significant toxicity. Numerous studies have demonstrated clear and durable survival advantages for patients undergoing complete resection of metastatic melanoma. Further, surgical resection can produce an immediate decrease in tumor burden with minimal morbidity and mortality at a reasonable cost.

Treatment of metastatic malignant melanoma

The rapid increase in incidence of malignant melanoma has not been associated with better therapeutic options over the years. Single-agent chemotherapy or immunotherapy remain the treatments of choice when systemic therapy is offered. Dacarbazine (DTIC) is the chemotherapy of choice with a response rate of 16%. Other chemotherapies, including cisplatinum, paclitaxel, docetaxel and the DTIC analogue temozolomide, have shown activity in this disease. Based on their single-agent activity, several combination chemotherapies have been investigated with preliminary results that appeared promising. However, in randomized phase III trials the two most active chemotherapy combination regimens, cisplatin, vinblastine, and DTIC (CVD) and the Dartmouth regimen (DTIC, cisplatin, bischloroethylnitrosourea , and tamoxifen), did not prove to be superior to single-agent DTIC for overall survival. Immunotherapy with either interleukin (IL)-2 or interferon (IFN) has demonstrated response rates of 10% to 15% in appropriately selected patients. In patients who achieve a complete response, responses can be of greater durability than those with chemotherapy. However, IL-2 and IFN administration are associated with multiple side effects, and only physicians experienced in the management of such therapies should administer them. The potential benefit of combining chemotherapy with immunotherapy has led to multiple phase II trials of biochemotherapy that appeared to be associated with higher response rates and longer median survivals. However, several phase III trials have been completed that have not consistently demonstrated an improvement in either response rates or overall survival, and these approaches to therapy cannot be routinely recommended outside the context of a clinical trial. The surgical resection of isolated metastatic disease has demonstrated an important palliative benefit in those patients who present with solitary single-organ disease with the exception of the liver. Radiation has an important role in the palliative management of brain metastasis and symptomatic bony metastasis. Both stereotactic radiosurgery and whole brain radiotherapy have been used alone and in combination to benefit patients in this troubling clinical circumstance. Isolated limb perfusion and a newer technique, isolated limb infusion have demonstrated high response rates for those uncommon patients who develop recurrent disease isolated to a limb. In our opinion, if complete metastasectomy is not feasible and in the absence of brain metastases, single-agent IL-2 is a good initial treatment choice in appropriately selected patients. Single-agent chemotherapy with DTIC is the treatment of choice for patients who are not candidates for IL-2. Adoptive immunotherapy combining nonmyeloablative chemotherapy with high-dose IL-2 is a potentially promising therapeutic strategy under investigation. Targeted therapy is also an area of promising development as single agents, in combination, and combined with chemotherapy. The latter will be the focus of at least one upcoming cooperative group phase III trial.

Surgical management of distant metastases

Although the location of metastases is of prognostic importance in stage IV melanoma, as seen in the revised AJCC staging classification system and other studies, certain guiding principles apply to patients who have any stage IV disease. Close follow-up of any patient who has melanoma may identify surgically resectable metastatic disease, although this method is controversial. Components of this monitoring may include careful questioning to determine symptoms, such as cough, abdominal pain, or headaches; physical examination for evidence of skin, soft tissue, and lymph node metastases; and screening tools, such as radiographs and laboratory tests. Identifying patients who have metastatic disease at the earliest stage possible is crucial for surgical resection to be an option. Patients should also be thoughtfully evaluated for the possibility of a complete surgical re-section. Complete metastectomy, regardless of the anatomic site, confers survival advantages not seen with other treatment modalities. This aggressive surgical approach should be tempered with the knowledge that incomplete resections put patients at increased risk without any proven survival benefit, and should be reserved only for palliation of symptoms. Systemic adjuvant therapies for stage IV melanoma are evolving, but do not yet confer the survival advantage of complete surgical resection. Until novel drug therapies show efficacy and significantly prolong survival in patients who have stage IV disease, careful consideration should be given to a complete metastectomy if technically feasible.

The TLR-7 agonist, imiquimod, enhances dendritic cell survival and promotes tumor antigen-specific T cell priming: relation to central nervous system antitumor immunity

Immunotherapy represents an appealing option to specifically target CNS tumors using the immune system. In this report, we tested whether adjunctive treatment with the TLR-7 agonist imiquimod could augment antitumor immune responsiveness in CNS tumor-bearing mice treated with human gp100 + tyrosine-related protein-2 melanoma-associated Ag peptide-pulsed dendritic cell (DC) vaccination. Treatment of mice with 5% imiquimod resulted in synergistic reduction in CNS tumor growth compared with melanoma-associated Ag-pulsed DC vaccination alone. Continuous imiquimod administration in CNS tumor-bearing mice, however, was associated with the appearance of robust innate immune cell infiltration and hemorrhage into the brain and the tumor. To understand the immunological mechanisms by which imiquimod augmented antitumor immunity, we tested whether imiquimod treatment enhanced DC function or the priming of tumor-specific CD8+ T cells in vivo. With bioluminescent, in vivo imaging, we determined that imiquimod dramatically enhanced both the persistence and trafficking of DCs into the draining lymph nodes after vaccination. We additionally demonstrated that imiquimod administration significantly increased the accumulation of tumor-specific CD8+ T cells in the spleen and draining lymph nodes after DC vaccination. The results suggest that imiquimod positively influences DC trafficking and the priming of tumor-specific CD8+ T cells. However, inflammatory responses induced in the brain by TLR signaling must also take into account the local microenvironment in the context of antitumor immunity to induce clinical benefit. Nevertheless, immunotherapeutic targeting of malignant CNS tumors may be enhanced by the administration of the innate immune response modifier imiquimod.

Central Nervous System Tumor Immunity Generated by a Recombinant Listeria monocytogenes Vaccine Targeting Tyrosinase Related Protein-2 and Real-Time Imaging of Intracranial Tumor Burden

OBJECTIVE

Previously, we demonstrated that a recombinant Listeria monocytogenes (rLM) vector encoding the melanoma-associated antigen, tyrosinase related protein (TRP)-2, could successfully treat subcutaneous B16 melanomas. The purpose of the present study was twofold: 1) to test whether this rLM-nucleoprotein (NP)/TRP-2 could generate antitumor immunity to a B16 tumor challenge in the immunologically privileged central nervous system (CNS) and 2) to develop a noninvasive imaging modality to monitor tumor progression in the brain after immunotherapy.

METHODS

Mice were vaccinated with either a control rLM strain expressing only a viral antigen (rLM-NP) or a strain expressing both the viral epitope and TRP-2 (rLM-NP/TRP-2). These mice were then analyzed for their ability to mount tumor-specific T-cell responses, to generate protective antitumor immunity to a CNS tumor challenge, and for the localization of T cells at the tumor site. To noninvasively measure tumor growth within the CNS in vivo, we developed a B16 cell line expressing firefly luciferase that could be readily detected via bioluminescent imaging.

RESULTS

Vaccination with rLM-NP/TRP-2 induced a robust, tumor-specific CD8 T-cell response to the dominant cytotoxic T lymphocyte epitope of TRP-2 and selective interferon-gamma secretion when cocultured with B16 melanoma cells in vitro. Significant decreases in CNS tumor sizes were easily visualized in mice vaccinated with rLM-NP/TRP-2 compared with mice that received a control rLM expressing the NP epitope alone (rLM-NP). The subsequent decreased tumor size and extension of survival induced by rLM-NP/TRP-2 was similarly associated with an early increase of tumor infiltrating T cells.

CONCLUSION

The ability to treat tumors arising within the CNS is difficult because of the nature of the anatomic confines of the brain and a microenvironment that may not promote immune responsiveness. These studies describe an in vivo bioluminescent imaging system to monitor CNS tumor growth in mice, which we successfully used to document decreased intracranial tumor progression and size after vaccination with rLM-NP/TRP-2. The results suggest that metastatic tumors in the CNS can be targeted immunotherapeutically without overt autoimmune toxicity.

Central nervous system as exclusive site of disease in patients with melanoma: treatment and clinical outcome of two cases

The central nervous system (CNS) is a favourite site of metastasis in advanced melanoma and, despite the improvement obtained in the control of brain metastasis, most patients die as a result of extracranial progression of the disease. CNS primary malignant melanoma is a rare entity and the diagnosis is generally made after the exclusion of a primary cutaneous or mucosal/retinal malignant melanoma, as differential histological diagnosis between primary and metastatic origins is often difficult. From a review of the literature, patients with primary brain melanoma or exclusive (and limited) brain metastasis in the absence of extracranial melanoma present a relatively good prognosis if adequately treated with aggressive locoregional treatments (neurosurgery and/or radiotherapy) and, later, with drugs able to cross the blood-brain barrier (i.e. fotemustine). In this letter, we describe the history, treatment and favourable clinical outcome of two patients with melanoma and CNS as the exclusive site of disease.

Inhibition of O6-methylguanine-DNA methyltransferase by glucose-conjugated inhibitors: comparison with nonconjugated inhibitors and effect on fotemustine and temozolomide-induced cell death

The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) is an important suicide enzyme involved in the defense against O(6)-alkylating mutagens. It also plays a role in the resistance of tumors to anticancer drugs targeting the O(6)-position of guanine, such as temozolomide and fotemustine. Several potent MGMT inhibitors have been developed sensitizing cells to O(6)-alkylating agents. Aimed at targeting MGMT inhibitors to tumor cells, we synthesized MGMT inhibitory compounds conjugated with glucose to improve uptake in tumor cells. Here, we compared O(6)-benzylguanine, O(6)-2-fluoropyridinylmethylguanine (O(6)FPG), O(6)-3-iodobenzylguanine, O(6)-4-bromothenylguanine, and O(6)-5-iodothenylguanine with the corresponding C8-linker beta-d-glucose derivatives. All glucose conjugated inhibitors were 3- to 5-fold less effective than the corresponding nonconjugated drugs as to MGMT inhibition that was measured in cell extracts (in vitro) and cultivated HeLaS3 cells (in vivo). Except for O(6)FPG, IC(50) values of the guanine derivatives applied in vitro and in vivo were correlated. A similar correlation was not obvious for the corresponding glucosides, indicating differences in cellular uptake. C8-alpha-d-glucosides were less effective than beta-glucosides. From the newly developed glucose-conjugated inhibitors tested, O(6)-4-bromothenylguanine-C8-beta-d-glucoside (O(6)BTG-C8-betaGlu) was most potent in inhibiting MGMT both in vitro and in vivo. At a concentration of 0.1 microM, it inhibited cellular MGMT to completion. It was not toxic, even when applied chronically to cells at high dose (up to 20 microM). O(6)BTG-C8-betaGlu strongly potentiated the killing effect of fotemustine and temozolomide, causing reversal from MGMT+ to MGMT- phenotype. Therefore, O(6)BTG-C8-betaGlu seems to be especially suitable for approaching MGMT inhibitor targeting in tumor therapy.