Brain metastases in melanoma: a European perspective

Survival outcomes following craniotomy for intracranial metastases from an unknown primary

Introduction

Management of patients with intracranial metastases from an unknown primary tumor (CUP) varies compared to those with metastases of known primary tumor origin (CKP). The National Institute for Health and Care Excellence (NICE) recognizes the current lack of research to support the management of CUP patients with brain metastases. The primary aim was to compare survival outcomes of CKP and CUP patients undergoing early resection of intracranial metastases to understand the efficacy of surgery for patients with CUP.

Methods

A retrospective study was performed, wherein patients were identified using a pathology database. Data was collected from patient notes and trust information services. Surgically managed patients during a 10-year period aged over 18 years, with a histological diagnosis of intracranial metastasis, were included.

Results

298 patients were identified, including 243 (82.0%) CKP patients and 55 (18.0%) CUP patients. Median survival for CKP patients was 9 months (95%CI 7.475–10.525); and 6 months for CUP patients (95%CI 4.263–7.737, p = 0.113). Cox regression analyses suggest absence of other metastases (p = 0.016), age (p = 0.005), and performance status (p = 0.001) were positive prognostic factors for improved survival in cases of CUP. The eventual determination of the primary malignancy did not affect overall survival for CUP patients.

Conclusions

There was no significant difference in overall survival between the two groups. Surgical management of patients with CUP brain metastases is an appropriate treatment option. Current diagnostic pathways specifying a thorough search for the primary tumor pre-operatively may not improve patient outcomes.

Current treatment options of brain metastases and outcomes in patients with malignant melanoma

The prognosis for patients with melanoma who have brain metastases is poor, a median survival does not exceed 4-6 months. There are no uniform standards of treatment for patients with melanoma brain metastases (MBMs). The most preferred treatment approaches include local therapy - surgical resection and/or stereotactic radiosurgery (SRS). The role of whole brain radiotherapy (WBRT) as an adjuvant to local therapy is controversial. WBRT remains a palliative approach for those patients who have multiple MBMs with contraindications for surgery or SRS, or/and poor performance status, or/and very widespread extracranial metastases. Corticosteroids have been used in palliative treatment of MBMs as relief from symptoms related to intracranial pressure and edema. In recent years, the development of new systemic therapeutic strategies has been observed. Various modalities of systemic treatment include chemotherapy, immunotherapy and targeted therapy. Also, multimodality management in different combinations is a common strategy. Decisions regarding the use of specific treatment modalities are dependent on patient's performance status, and the extent of both intracranial and extracranial disease. This review summarizes current treatment options, indications and outcomes in patients with brain metastases from melanoma.

Stereotactic radiosurgery and immunotherapy for metastatic spinal melanoma

The management of metastatic spinal melanoma involves maximizing local control, preventing recurrence, and minimizing treatment-associated toxicity and spinal cord damage. Additionally, therapeutic measures should promote mechanical stability, facilitate rehabilitation, and promote quality of life. These objectives prove difficult to achieve given melanoma's elusive nature, radioresistant and chemoresistant histology, vascular character, and tendency for rapid and early metastasis. Different therapeutic modalities exist for metastatic spinal melanoma treatment, including resection (definitive, debulking, or stabilization procedures), stereotactic radiosurgery, and immunotherapeutic techniques, but no single treatment modality has proven fully effective. The authors present a conceptual overview and critique of these techniques, assessing their effectiveness, separately and combined, in the treatment of metastatic spinal melanoma. They provide an up-to-date guide for multidisciplinary treatment strategies. Protocols that incorporate specific, goal-defined surgery, immunotherapy, and stereotactic radiosurgery would be beneficial in efforts to maximize local control and minimize toxicity.

Current concepts of metastasis in melanoma

The main cause of death in melanoma patients is widespread metastases. Staging of melanoma is based on the primary tumor thickness, ulceration, lymph node and distant metastases. Metastases develop in regional lymph nodes, as satellite or in-transit lesions, or in distant organs. Lymph flow and chemotaxis is responsible for the homing of melanoma cells to different sites. Standard pathologic evaluation of sentinel lymph nodes fails to find occult melanoma in a significant proportion of cases. Detection of small numbers of malignant melanoma cells in these and other sites, such as adjacent to the primary site, bone marrow or the systemic circulation, may be enhanced by immunohistochemistry, reverse transcription PCR, evaluation of lymphatic vessel invasion and proteomics. In the organs to which melanoma cells metastasize, extravasation of melanoma cells is regulated by adhesion molecules, matrix metalloproteases, chemokines and growth factors. Melanoma cells may travel along external vessel lattices. After settling in the metastatic sites, melanoma cells develop mechanisms that protect them against the attack of the immune system. It is thought that one of the reasons why melanoma cells are especially resistant to killing is the fact that melanocytes (cells from which melanoma cells derive) are resistant to such noxious factors as ultraviolet light and reactive oxygen species. Targeted melanoma therapies are, so far, largely unsuccessful, and new ones, such as adjuvant inhibition of melanogenesis, are under development.

Revisiting the role of systemic therapies in patients with metastatic melanoma to the CNS

The CNS is a common site of metastasis in patients with malignant melanoma. Locoregional control either with surgery or radiotherapy is first-line treatment for patients with brain metastasis should they be suitable candidates. For those patients who are not and those who progress after previous treatment, there is an unmet clinical need for effective systemic therapies. Systemic cytotoxics, such as temozolamide and fotemustine, have only modest activity, resulting in a median progression-free survival ranging from 1-2 months, in patients with metastatic melanoma to the brain. Newer systemic treatments such as vemurafenib and ipilimumab have been approved for the treatment of melanoma, but evidence regarding their activity in brain metastases is inconclusive due to the limited access of patients to clinical trials. This is now being revised and more data are emerging supporting the inclusion of patients with brain metastasis in trials. In this review, the authors present data regarding the efficacy of systemically administered therapies in patients with metastatic melanoma to the brain.

Genes overexpressed in different human solid cancers exhibit different tissue-specific expression profiles

We have analyzed gene expression in different normal human tissues and different types of solid cancers derived from these tissues. The cancers analyzed include brain (astrocytoma and glioblastoma), breast, colon, endometrium, kidney, liver, lung, ovary, prostate, skin, and thyroid cancers. Comparing gene expression in each normal tissue to 12 other normal tissues, we identified 4,917 tissue-selective genes that were selectively expressed in different normal tissues. We also identified 2,929 genes that are overexpressed at least 4-fold in the cancers compared with the normal tissue from which these cancers were derived. The overlap between these two gene groups identified 1,340 tissue-selective genes that are overexpressed in cancers. Different types of cancers, including different brain cancers arising from the same lineage, showed differences in the tissue-selective genes they overexpressed. Melanomas overexpressed the highest number of brain-selective genes and this may contribute to melanoma metastasis to the brain. Of all of the genes with tissue-selective expression, those selectively expressed in testis showed the highest frequency of genes that are overexpressed in at least two types of cancer. However, colon and prostate cancers did not overexpress any testis-selective gene. Nearly all of the genes with tissue-selective expression that are overexpressed in cancers showed selective expression in tissues different from the cancers' tissue of origin. Cancers aberrantly expressing such genes may acquire phenotypic alterations that contribute to cancer cell viability, growth, and metastasis.

Dose-intensified bi-weekly temozolomide in patients with asymptomatic brain metastases from malignant melanoma: a phase II DeCOG/ADO study

BACKGROUND

Temozolomide has shown some efficacy in metastatic melanoma and recently received extended approval to treat brain tumours. The purpose of this study was to test a dose-intensified regimen of temozolomide in melanoma patients with brain metastases in a prospective, open-label, multicentre phase II trial.

PATIENTS AND METHODS

Forty-five patients with asymptomatic brain metastases from melanoma were stratified into arm A (no prior chemotherapy; n = 21) and arm B (previous chemotherapy; n = 24). Patients received oral temozolomide either 150 mg/m(2)/day (arm A) or 125 mg/m(2)/day (arm B), days 1-7 and 15-21, every 28 days. The primary study end point was objective response, and secondary end points were overall survival and safety.

RESULTS

Two patients (4.4%) achieved a partial response (PR) in brain metastases (one in each arm), one of them (2.2%) also showing a PR in extracerebral disease. An additional five patients (11.1%; two in arm A, three in arm B) showed disease stabilisation (SD) in brain and other sites. However, 82% revealed progressive disease (PD) already evident 8 weeks after therapy initiation. Median survival time from therapy onset was 3.5 months (range 0.7-8.3; arm B) and 4.3 months (range 1.6-11.8; arm A), P = 0.43. Dose modifications and prolongations of therapy cycles due to toxicity were required in 20% of patients. Grade 3/4 toxicity was observed in one patient only (2.2%).

CONCLUSIONS

Oral administration of temozolomide given bi-weekly is well-tolerated in melanoma patients with cerebral involvement. However, the efficacy is limited, with lower than 5% objective responses observed in brain and extracerebral metastases.

Multimodality treatment of melanoma brain metastases incorporating stereotactic radiosurgery (SRS)

BACKGROUND

Brain metastases are a frequent complication in advanced melanoma. A 3.6 to 4.1-month median survival has been reported after treatment with whole brain radiotherapy. We performed a retrospective analysis of our institutional experience of multimodality treatment utilizing linear accelerator (Linac)-based stereotactic radiosurgery (SRS).

METHODS

Forty-four melanoma patients with brain metastases underwent 66 SRS treatments for 156 metastatic foci between 1999 and 2004. Patients were treated with initial SRS if <or=5 brain metastases were present. All patients had Karnofsky Performance Status (KPS)>or=70, but 37 patients had active systemic metastases (Recursive Partition Analysis Class 2). Survival was calculated from the time of diagnosis of brain metastases. Minimum follow-up was 1 year after SRS. The potential role of prognostic factors on survival was evaluated including age, sex, interval from initial diagnosis to brain metastases, surgical resection, addition of whole brain radiotherapy (WBRT), number of initial metastases treated, and number of SRS treatments using Cox univariate analysis.

RESULTS

The median survival of melanoma patients with brain metastases was 11.1 months (95% confidence interval [CI]: 8.2-14.9 months) from diagnosis. One-year and 2-year survivals were 47.7% and 17.7%, respectively. There was no apparent effect of age or sex. Surgery or multiple stereotactic radiotherapy treatments were associated with prolonged survival. Addition of WBRT to maintain control of brain metastases in a subset of patients did not improve survival.

CONCLUSIONS

Our results suggest that aggressive treatment of patients with up to 5 melanoma brain metastases including SRS appears to prolong survival. Subsequent chemotherapy or immunotherapy after SRS may have contributed to the observed outcome.

Radiosurgery for the treatment of spinal melanoma metastases

BACKGROUND

The role of stereotactic radiosurgery in treating metastatic melanoma involving the spine has previously been limited. Conventional external beam radiotherapy lacks the precision to allow delivery of large single-fraction doses of radiation and simultaneously to limit the dose delivered to radiosensitive structures such as the spinal cord. This study evaluated the clinical efficacy of radiosurgery for the treatment of melanoma spinal metastases in 28 patients.

METHODS

Thirty-six melanoma spine metastases were treated with a single-session radiosurgery technique (1 cervical, 11 thoracic, 13 lumbar, and 11 sacral) with a follow-up period of 3-43 months (median 13 months). Tumor volume ranged from 4.1 to 153 cm3 (mean 47.6 cm3). Twenty-three of the 36 lesions had received prior external beam irradiation.

RESULTS

Maximum tumor dose was maintained at 17.5-25 Gy (mean 21.7 Gy). Spinal cord volume receiving > 8 Gy ranged from 0.0 to 0.7 cm3 (mean 0.26 cm3); spinal canal volume at the cauda equina level receiving > 8 Gy ranged from 0.0 to 3.5 cm3 (mean 0.98 cm3). No radiation-induced toxicity occurred during the follow-up period. Axial and radicular pain improved in 27 of 28 patients (96%) who were treated primarily for pain. Long-term tumor control was seen in 3 of 4 cases treated primarily for radiographic tumor progression. Two patients went on to require open surgical intervention for tumor progression resulting in neurological deficit.

CONCLUSIONS

Spinal radiosurgery offers a therapeutic modality for the safe delivery of large dose fractions of radiation therapy in a single fraction for the management of spinal metastases in patients with advanced melanoma that are often poorly controlled with alternative conventional external beam radiation therapy, and is successful even in patients with previously irradiated lesions.

Surgical treatment of stage IV melanoma

Surgical therapy plays an important role in the management of selected patients with metastatic melanoma. Patients are frequently symptomatic from metastatic lesions, have few effective therapeutic options, and are faced with dismal outcomes. Surgical resection may provide successful palliation of symptomatic lesions with low morbidity and operative mortality. In carefully selected patients, resections performed with curative intent may result in improved survival if a pattern of disease recurrence suggestive of favorable tumor biology is present, and if complete resection of tumor is achieved. Because the majority of post-surgical metastatic patients eventually relapse and succumb to distant disease, adjuvant immunotherapeutic strategies are currently being evaluated.