Citations

Abstract BACKGROUND Dexamethasone is commonly used to manage peritumoral edema and alleviate neurologic symptoms in patients with intracranial tumors. The optimal dexamethasone dose for brain metastases is unknown and widely variable. Recent literature reports the most common regimen is 4 mg four times daily. However, the half-life of dexamethasone is 35-54 hours, suggesting that such frequent dosing may be unnecessary. We explored the dose-effect relationship of dexamethasone on brain metastases patient outcomes to improve quality of care. METHODS We retrospectively identified 100 patients (1/1/2016 – 12/31/2022) with brain metastases who were treated with dexamethasone and had adequate follow-up. All patients received standard oncologic care including chemotherapy, radiotherapy, and/or surgical intervention. We evaluated the association between dexamethasone dosing regimens (< 4 mg twice daily versus > 4 mg three times daily), clinical outcomes (performance status, clinical and radiographic response to corticosteroids, survival), and dexamethasone adverse effects during the acute presentation and at first neuro-oncologic follow-up. RESULTS Seventy-two patients received less frequent dexamethasone dosing (< 4 mg twice daily), while 28 received more frequent dexamethasone dosing (> 4 mg three times daily). Patients with higher frequency dexamethasone dosing were more likely to have radiographic evidence of midline shift (p < 0.001), compression of ventricles (p < 0.001), and herniation (p = 0.0020) at presentation. Those with more frequent dosing more often demonstrated radiographic response to dexamethasone (67.9% vs. 45.8%, p = 0.0323), but there were no differences in symptomatic improvement, Karnofsky Performance Status, seizure reduction, survival, or the frequency of adverse events (e.g., hyperglycemia, hypertension, infection, psychosis) between the two cohorts. CONCLUSIONS These results suggest that for most patients with brain metastases, less frequent dexamethasone dosing may lead to clinical outcomes that are similar to those patients who received more frequent dosing. However, higher doses of dexamethasone can be considered for those with more concerning radiologic features.

Abstract PURPOSE For large brain metastases, it is unknown whether single fraction stereotactic radiosurgery (sSRS) or multi-fraction stereotactic radiosurgery (fSRS) is optimal. We aimed to compare rates of local progression and necrosis between sSRS and fSRS for large brain metastases. METHODS Patients with intact or resected brain metastases with a target volume ≥ 4.2 cc (corresponding to a diameter ≥ 2 cm) treated with Gamma Knife (GK) or linear accelerator-based SRS from 2014-2022 were included in this retrospective review. RESULTS A total of 343 large brain metastases in 276 patients were included; 171 lesions were treated with sSRS (96% with GK) and 172 lesions with fSRS (100% with linear accelerator). Median lesion volume was 19.8 cc and 8.4 cc for fSRS and sSRS, respectively. Resection was performed prior to SRS in 228 (66%), with the remaining 115 metastases treated intact. There was no difference in rate of local progression between sSRS versus fSRS, or between resected versus intact targets (p >0.8 for both). Cumulative incidence of local progression (with death as a competing risk) at 1 and 3 years for patients receiving sSRS was 24% and 30%, respectively, compared to 22% and 34% for fSRS. FSRS was associated with significantly higher rates of necrosis than sSRS (HR 5.58, 2.38-13.08, p < 0.001). This association remained significant after controlling for target volume. Cumulative incidence of necrosis (with death as a competing risk) at 1 and 3 years for patients receiving sSRS was 1% and 3%, respectively, compared to 10% and 18% for fSRS. Necrosis rates were significantly higher with fSRS for both intact and resected targets (P < 0.02 for both). CONCLUSION While local control for large resected or intact brain metastases appears similar after sSRS or fSRS, this retrospective study shows higher rates of necrosis after fSRS. Prospective validation is needed.

Abstract BACKGROUND Dexamethasone is commonly used for symptomatic management in primary central nervous lymphoma (PCNSL). The optimal dosing scheme for dexamethasone is unknown and practice patterns widely vary among clinicians. In this study, we explored the dose-effect relationship of dexamethasone on PCNSL outcomes to better influence quality care for these patients. METHODS We retrospectively identified 24 Mayo Clinic patients (1/1/2018 – 12/31/2022) with pathologically confirmed PCNSL who received dexamethasone. All patients otherwise received standard oncologic care including methotrexate-based systemic chemotherapy and/or radiotherapy. The association between dexamethasone dosing regimens and clinical outcomes (performance status, clinical and radiographic response, survival) in addition to potential adverse effects were evaluated in the acute phase of presentation and at first post-treatment oncology follow up. RESULTS Nine patients received less frequent dexamethasone dosing (4 mg twice daily or less), while 15 received more frequent dexamethasone dosing (4 mg four times daily). Fourteen patients received dexamethasone prior to biopsy, 2 of which (1 in each cohort) had a non-diagnostic biopsy and required a second procedure 3 weeks to 3 months later to confirm PCNSL diagnosis. There were no statistically significant differences in time to diagnosis from presentation or clinical and radiographic improvement including Karnofsky Performance Status, reduction in seizures, or survival between the two cohorts. Additionally, there were no differences in the frequency of adverse events (e.g., hyperglycemia, hypertension, infection, psychosis) between the two dosing regimens. CONCLUSIONS These results suggest that more frequent dexamethasone dosing is not associated with better clinical outcomes in the symptomatic management of PCNSL. Twice daily or less frequent dosing can be considered without compromising patient outcomes.

ABSTRACT Introduction Proton craniospinal irradiation (pCSI) is a treatment option for leptomeningeal disease (LMD), which permits whole neuroaxis treatment while minimizing toxicity. Despite this, patients inevitably experience progression. Adding systemic therapy to pCSI may improve outcomes. Methods In this single-institution retrospective case series, we present the feasibility of treatment with pCSI (30Gy, 10 fractions) and an immune checkpoint inhibitor (ICI) in two sequential patients with LMD from melanoma. Results The first patient developed LMD related to BRAF V600E-mutant melanoma after prior ICI and BRAF-targeted therapy. After pCSI with concurrent nivolumab, the addition of relatlimab, and BRAF-targeted therapy, he remained alive 7 months after LMD diagnosis despite central nervous system progression. The second patient developed LMD related to BRAF-wildtype melanoma after up-front ICI. He received pCSI with concurrent ipilimumab and nivolumab, then nivolumab maintenance. Though therapy was held for ICI hepatitis, the patient remained progression-free 5 months after LMD diagnosis. Conclusion Adding an ICI to pCSI is feasible for patients with LMD and demonstrates a tolerable toxicity profile. While prospective evaluation is ultimately warranted, pCSI with ICI may confer survival benefits, even after prior ICI.

Introduction: The differential diagnosis of a spinal intradural extramedullary mass lesion is broad and includes meningioma, schwannoma, neurofibroma, leptomeningeal metastasis, and myxopapillary ependymoma. Though rare, lymphoma should be included in the differential diagnosis of a dural mass lesion. Case Report: A 38-year-old man presented with back pain that progressed over 1 month with associated focal tenderness over his mid to lower thoracic spine. He developed intermittent numbness of the bilateral lower extremities, nuchal rigidity, difficulty sleeping, and night sweats. A magnetic resonance imaging of the thoracic spine demonstrated a dorsal intradural extramedullary enhancing lesion from T7 to T10 extending outside the spinal canal. Dural thickening across the entire circumference of the spinal cord was noted. Computed tomography (CT)-guided biopsy of the thoracic lesion was performed, and pathology was consistent with follicular lymphoma. Fluorodeoxyglucose positron emission tomography:CT demonstrated no systemic disease. Bone marrow biopsy was negative for malignancy. Symptoms resolved with dexamethasone therapy. He was treated with bendamustine and rituximab with follow-up positron emission tomography:CT 2 months later demonstrating a complete response. Conclusions: Lymphoma can rarely present as an isolated dural lesion and should be considered in the differential diagnosis of intradural extramedullary spinal mass lesions. Prompt diagnosis and initiation of treatment can lead to complete response and resolution of symptoms.

Abstract Background Neurofibromatosis type 2 (NF2)-related schwannomatosis is an autosomal dominant tumor-predisposition syndrome characterized by bilateral vestibular schwannomas (VS). In patients with VS associated with NF2, vascular endothelial growth factor A inhibitor, bevacizumab, is a systemic treatment option. The aim of this study is to retrospectively evaluate NF2 patient responses to bevacizumab on VS growth and symptom progression. Methods This is a retrospective analysis of patients seen at the Mayo Clinic Rochester Multidisciplinary NF2 Clinic. Results Out of 76 patients with NF2 evaluated between 2020 and 2022, we identified 19 that received treatment with bevacizumab. Thirteen of these patients discontinued bevacizumab after median treatment duration of 12.2 months. The remaining 6 patients are currently receiving bevacizumab treatment for a median duration of 9.4 months as of March, 2023. Fifteen patients had evaluable brain MRI data, which demonstrated partial responses in 5 patients, stable disease in 8, and progression in 2. Within 6 months of bevacizumab discontinuation, 5 patients had rebound growth of their VS greater than 20% from their previous tumor volume, while 3 did not. Three patients with rebound growth went on to have surgery or irradiation for VS management. Conclusions Our single-institution experience confirms prior studies that bevacizumab can control progression of VS and symptoms associated with VS growth. However, we note that there is the potential for rapid VS growth following bevacizumab discontinuation, for which we propose heightened surveillance imaging and symptom monitoring for at least 6 months upon stopping anti-VEGF therapy.

Abstract BACKGROUND Although glioblastoma (GBM) is the most common malignant primary brain tumor in adults, extracranial metastasis is rare, occurring in <2% of cases. This rarity has been attributed to the blood brain barrier, immunologic factors, lack of traditional lymphatics in the brain, and the poor prognosis of GBM, limiting its opportunity to metastasize. When GBM does metastasize, bone is the most common destination. GBM may spread hematogenously to bone, especially to vertebral bodies via the surrounding venous plexus. In this single-institution study, we review the clinical characteristics of GBM patients with osseous metastases and evaluate potential risk factors and prognostic significance. MATERIAL AND METHODS Using an institutional database, we identified and retrospectively analyzed 6 GBM patients with osseous metastases and studied their demographics, tumor genetics, clinical courses, and outcomes. RESULTS Five of 6 (83%) GBM patients with osseous metastases were male, with a median age of 46 years at GBM diagnosis (range: 20-84). All patients had IDH wild type and MGMT unmethylated GBM with mutations in TP53. Two patients (33%) were initially diagnosed with gliosarcoma. All patients were treated with surgical resection followed by radiation with concurrent and adjuvant temozolomide. Five patients (83%) received bevacizumab for vasogenic edema (n=4) or intracranial tumor progression (n=1) prior to bone metastasis diagnosis. Bone metastases were diagnosed a median of 12.2 months (range: 5.3-35.2) after GBM diagnosis and 4.8 months after starting bevacizumab (range: 3.5-13.2). Two patients (33%) received immune checkpoint inhibitor therapy and two patients (33%) received tumor-treating fields prior to bone metastasis discovery. Bone metastases were symptomatic in 2 patients, presenting with back pain (n=1) and leg weakness and urinary incontinence (n=1). Three patients (50%) had concurrent metastases to other organs. Osseous metastases were biopsy-confirmed in 3 (50%) cases, while the other 3 patients had no known alternative malignancy to explain their bone metastases. After osseous metastasis discovery, the median survival was 27 days (range: 13-225). CONCLUSION Most of our GBM patients with osseous metastases were male and most, but not all, were young at GBM diagnosis. Tumor genetics common to all patients included IDH wild type, MGMT unmethylated status, and TP53 mutation, which may be important for osseous metastasis. Most patients received bevacizumab, which may be associated with earlier metastasis. While rare, metastatic GBM should be within the differential for GBM patients with bone pain or progressive neurologic symptoms, as osseous metastases portend a dismal prognosis in an already aggressive malignancy.

Abstract BACKGROUND Neurofibromatosis type 2-related schwannomatosis (NF2) is an autosomal dominant tumor-predisposition syndrome characterized by bilateral vestibular schwannomas (VS) as well as other nervous system tumors. Management decisions for NF2-related VS are typically predicated on tumor size, associated symptoms, patient age, and comorbidities. Observation, surgical resection, and stereotactic radiosurgery can be viable options. In patients with VS associated with NF2, vascular endothelial growth factor A (VEGF-A) inhibitor, bevacizumab, is a systemic treatment option. In this single institution study, we review our clinical experience in patients with NF2 who received bevacizumab for VS and evaluate the effect of bevacizumab treatment on VS growth and symptom progression. MATERIAL AND METHODS This is a retrospective analysis of patients seen at the Mayo Clinic Rochester Multidisciplinary NF2 Clinic. Three-dimensional volumetric data for VS were measured using manual segmentation with Visage PACS software under the direct supervision of a board-certified neuroradiologist. RESULTS Out of 76 patients with NF2 evaluated in the past 3 years, we identified 19 that received treatment with bevacizumab. Median age of NF2 diagnosis was 19 years (range 0.5-61) with a median NF2 phenotype severity score of 2 (range 1-3). Thirteen of these patients have discontinued bevacizumab, accounting for a median duration of 12.2 months (range 3.3-88 months) of bevacizumab treatment. Bevacizumab was discontinued due to hypertension (n=5), proteinuria and renal dysfunction (n=3), tumor progression (n=2), fatigue or other intolerance (n=2), or non-compliance (n=1). The remaining 6 patients are currently receiving bevacizumab treatment for a median duration of 9.4 months as of March 2023 (range 3.7-48.3 months). Fifteen patients had brain MRI data available to evaluate VS change during bevacizumab treatment, with partial response observed in 5 patients, stable disease in 8, and progression in 2. Ten of the 13 patients who stopped bevacizumab had MRI data to evaluate VS change following treatment termination. Within 6 months of bevacizumab discontinuation, 6 patients had rebound growth of their VS between 21-95% from their previous tumor volume, while 4 did not. Three patients with rebound growth went on to have surgery or irradiation for VS management. CONCLUSION Our single institution experience confirms that bevacizumab can slow progression of VS and symptoms associated with VS growth. However, we note that there is the potential for rapid VS growth following bevacizumab discontinuation, for which we propose heightened surveillance imaging and symptom monitoring for at least 6 months upon stopping anti-VEGF therapy.