Efficacy of BRAF Inhibitors in Combination With Stereotactic Radiosurgery for the Treatment of Melanoma Brain Metastases: A Systematic Review and Meta-Analysis

Radiation and Melanoma: Where Are We Now?

PURPOSE OF REVIEW

This review summarizes the current role of radiotherapy for the treatment of cutaneous melanoma in the definitive, adjuvant, and palliative settings, and combinations with immunotherapy and targeted therapies.

RECENT FINDINGS

Definitive radiotherapy may be considered for lentigo maligna if surgery would be disfiguring. High risk, resected melanoma may be treated with adjuvant radiotherapy, but the role is poorly defined since the advent of effective systemic therapies. For patients with metastatic disease, immunotherapy and targeted therapies can be delivered safely in tandem with radiotherapy to improve outcomes. Radiotherapy and modern systemic therapies act in concert to improve outcomes, especially in the metastatic setting. Further prospective data is needed to guide the use of definitive radiotherapy for lentigo maligna and adjuvant radiotherapy for high-risk melanoma in the immunotherapy era. Current evidence does not support an abscopal response or at least identify the conditions necessary to reliably produce one with combinations of radiation and immunotherapy.

Efficiency and tolerance of second-line triple BRAF inhibitor/MEK inhibitor/anti-PD1 combined therapy in BRAF mutated melanoma patients with central nervous system metastases occurring during first-line combined targeted therapy: a real-life survey

Although current systemic therapies significantly improved the outcome of advanced melanoma, the prognosis of patient with central nervous system (CNS) metastases remains poor especially when clinically symptomatic. We aimed to investigate the efficiency of CNS targets and tolerance of second-line combined anti-PD1/dual-targeted anti-BRAF/anti-MEK therapy implemented in patients with CNS progression after initially efficient first-line combined targeted therapy in patients with BRAF-mutated melanoma in a real-life setting. A monocentric retrospective analysis including all such patients treated from January 2017 to January 2022 was conducted in our tertiary referral center. The response of CNS lesions to second-line triple therapy was assessed through monthly clinical and at least quarterly morphological (according to RECIST criteria) evaluation. Tolerance data were also collected. Seventeen patients were included with a mean follow-up of 2.59 (±2.43) months. Only 1 patient displayed a significant clinical and morphological response. No statistically significant difference was observed between patients receiving or not additional local therapy (mainly radiotherapy) as to response achievement. Immunotherapy was permanently discontinued in 1 patient owing to grade 4 toxicity. Mean PFS and OS after CNS progression were 2.59 and 4.12 months, respectively. In this real-life survey, the subsequent addition of anti-PD1 to combined targeted therapy in melanoma patients with upfront CNS metastases did not result in significant response of CNS targets in most BRAF mutated melanoma patients with secondary CNS progression after initially successful first-line combined targeted therapy.

Symptomatic brain metastases in melanoma

Although clinical outcomes in metastatic melanoma have improved in recent years, the morbidity and mortality of symptomatic brain metastases remain challenging. Response rates and survival outcomes of patients with symptomatic melanoma brain metastases (MBM) are significantly inferior to patients with asymptomatic disease. This review focusses upon the specific challenges associated with the management of symptomatic MBM, discussing current treatment paradigms, obstacles to improving clinical outcomes and directions for future research.

Concurrent Radiation and Targeted Therapy for Papillary Craniopharyngioma: A Case Report

Craniopharyngiomas are rare epithelial malformations in the sellar or suprasellar regions of the craniopharyngeal ducts. Complete surgical resection is difficult due to the location of the base of the skull and the risk of injury to vital neurological structures. Fractionated radiation is effective in controlling residual tumors, but craniopharyngiomas can progress during treatment. The papillary subtype is driven by BRAF V600E mutations. Treatment with BRAF and MEK inhibitors alone has a response rate of 90% but a median progression-free survival of only 12 months. A 57-year-old female presented in May 2017 with complaints of headaches and blurriness in her right eye. Brain MRI demonstrated a 2 cm suprasellar mass engulfing the right optic nerve and optic chiasm. The patient underwent a transsphenoidal hypophysectomy with pathology consistent with a benign pituitary adenoma. Follow-up imaging in August, however, showed recurrence, and a re-resection was performed which surprisingly demonstrated papillary craniopharyngioma. Due to subtotal resection, the patient elected to proceed with intensity-modulated radiation therapy (IMRT) to the tumor bed in April of 2018 with an intended dose of 5400 cGy. After treatment with 2160 cGy in 12 fractions, the patient experienced visual deterioration and progression of the cystic tumor. The patient underwent another debulking procedure but due to rapid recurrence, an endoscopic transsphenoidal fenestration was performed. On postoperative imaging, a cystic mass was still engulfing the right optic nerve and chiasm. Due to the extended break and limited radiation tolerance of the optic chiasm, we elected to re-treat the tumor with an additional 3780 cGy IMRT in conjunction with one cycle of Taflinar and Mekinist, which was completed in August 2018. The cumulative dose to the optic chiasm was 5940 cGy.The patient had an excellent clinical response to treatment with the improvement of vision in her right eye. A brain MRI on 3/29/2019 demonstrated no residual craniopharyngioma. Four-year follow-on CT scan showed no evidence of tumor recurrence. The patient had preservation of vision and did not suffer any late neurological toxicity or new endocrine deficiency. Surgical resection and radiation were ineffective at treating our patient's craniopharyngioma due to rapid cystic progression. This is the first case report in the literature detailing concurrent radiation therapy with BRAF and MEK inhibitors for papillary craniopharyngioma. Despite a suboptimal dose of radiation, our patient had no tumor recurrence and no late toxicity four years after treatment. This represents a potentially novel treatment strategy in this challenging entity.

Towards updated understanding of brain metastasis

Brain metastasis (BM) is a common complication in cancer patients with advanced disease and attributes to treatment failure and final mortality. Currently there are several therapeutic options available; however these are only suitable for limited subpopulation: surgical resection or radiosurgery for cases with a limited number of lesions, targeted therapies for approximately 18% of patients, and immune checkpoint inhibitors with a response rate of 20-30%. Thus, there is a pressing need for development of novel diagnostic and therapeutic options. This overview article aims to provide research advances in disease model, targeted therapy, blood brain barrier (BBB) opening strategies, imaging and its incorporation with artificial intelligence, external radiotherapy, and internal targeted radionuclide theragnostics. Finally, a distinct type of BM, leptomeningeal metastasis is also covered.

Circulating Tumor DNA Testing Supports Rapid Therapeutic Decision-Making in Metastatic Melanoma: A Case Report

Treatment of metastatic melanoma includes the option of targeted therapy in patients with driver BRAF mutations. BRAF-MEK inhibitor drugs improve survival in the approximately 50% of patients with melanoma that harbor BRAF mutations. As BRAF mutation detection in tissue often takes days to weeks, it is not always possible or timely to obtain BRAF status in tissue using immunohistochemistry or next generation sequencing. Plasma-derived circulating tumor DNA (ctDNA) is a potential alternative analyte in such treatment settings. We present a case of metastatic melanoma that was treated in an emergent setting using therapy supported by rapid PCR-based detection of ctDNA positive for a BRAF V600 mutation. In this rapidly deteriorating 53-year-old male with diffuse melanoma metastases and unknown BRAF mutation status requiring hospital admission, a plasma-based BRAF mutation detection supported treatment with targeted therapy, dabrafenib and trametinib. Same-day initiation of therapy resulted in swift amelioration allowing discharge within a week, followed by substantial clinical improvement over the following weeks. In cases requiring urgent clinical decision making, a plasma-based, near point-of-care detection system is useful in supporting targeted therapy decisions without the need for invasive and time-consuming biopsy.

Impact of Previous Local Treatment for Brain Metastases on Response to Molecular Targeted Therapy in BRAF-Mutant Melanoma Brain Metastasis: A Systematic Review and Meta-Analysis

Background

Melanoma brain metastases (BMs) are associated with poor prognosis and are the main cause of mortality in melanoma patients. BRAF inhibitors have shown intracranial activity in both treatment-naïve and previously treated BM patients. We aimed to investigate if there was any difference in response of BRAF inhibitors in these two cohorts.

Materials and Methods

Electronic database search included PubMed, Medline, and Cochrane library until March 2021 for studies with desired comparative outcomes. Outcomes of interest that were obtained for meta-analysis included intracranial response rate as the primary outcome and survival and safety outcomes as the secondary outcomes. Review Manager version 5.4 was used for data analysis.

Results

Three studies comprising 410 BRAF-mutated melanoma patients with BMs were included according to eligibility criteria. The comparative cohort included patients with treatment-naïve BMs (TN cohort; n = 255) and those who had progressive disease after receiving local brain treatment for BMs (PT cohort; n = 155). Meta-analysis revealed that BRAF inhibitors (vemurafenib and dabrafenib) and BRAF/MEK inhibitor combination (dabrafenib and trametinib) induced significantly higher intracranial disease control (OR 0.58 [95% CI: 0.34, 0.97], p = 0.04) and a trend toward improved progression-free survival (PFS) (HR 1.22 [95% CI: 0.98, 1.52], p = 0.08) in the PT cohort as compared to the TN cohort. Overall survival was not significantly different between the cohorts (HR 1.16 [95% CI: 0.89, 1.51], p = 0.28). Subgroup analysis revealed that PFS was significantly improved (HR 1.67 [95% CI: 1.06, 2.62], p = 0.03), and a trend toward improved OS (HR 1.62 [95% CI: 0.95, 2.75], p = 0.08) was achieved in patients receiving BRAF/MEK inhibitor combination and patients with BRAFv600K mutation receiving dabrafenib alone. No increase in overall adverse events (AEs), grade 3/4 AEs, and severe adverse events (SAEs) was observed between the cohorts.

Conclusions

BRAF inhibitors (plus MEK inhibitor) may achieve better intracranial disease stability in BRAF-mutant melanoma patients who have received previous local treatment for BMs.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/), identifier CRD42020185984.

Improving Brain Metastases Outcomes Through Therapeutic Synergy Between Stereotactic Radiosurgery and Targeted Cancer Therapies

Brain metastases are the most common form of brain cancer. Increasing knowledge of primary tumor biology, actionable molecular targets and continued improvements in systemic and radiotherapy regimens have helped improve survival but necessitate multidisciplinary collaboration between neurosurgical, medical and radiation oncologists. In this review, we will discuss the advances of targeted therapies to date and discuss findings of studies investigating the synergy between these therapies and stereotactic radiosurgery for non-small cell lung cancer, breast cancer, melanoma, and renal cell carcinoma brain metastases.