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Background The abscopal effect is a rare phenomenon whereby local radiation induces a proposed immune-mediated anti-tumor effect at distant sites. Given the growing use of immunotherapies and systemic immune checkpoint inhibitors in neuro-oncologic practice, we aimed to review prior studies pertaining to this phenomenon in the context of tumor shrinkage both within the central nervous system as well as distant disease sites. Methods A systematic review in accordance with the PRISMA guidelines was conducted to identify all studies which assessed the abscopal effect in patients with treated metastatic cancer to the brain and/or spine. Articles were included if they reported the abscopal effect in patients (case studies) or if the abscopal effect was explicitly analyzed in case series with cohorts of patients with metastatic brain or spine tumors. Laboratory investigations and clinical trials investigating new therapies were excluded. Results Twenty reports met inclusion criteria [16 case reports, 4 case series (n = 160), total n = 174]. Case reports of the abscopal effect were in relation to the following cancers: melanoma (6 patients), breast cancer (3), lung adenocarcinoma (2), non-small-cell lung cancer (2), hepatocellular carcinoma (1), and renal cell carcinoma (1). Eleven patients had irradiation to the brain and 2 to the spine. Patients undergoing whole brain radiotherapy (6) had an average dose of 33.6 Gy over 8–15 fractions, and those undergoing stereotactic radiosurgery (5) had an average dose of 21.5 Gy over 1–5 fractions. One patient had radiation to the body and an intracranial abscopal effect was observed. Most common sites of extracranial tumor reduction were lung and lymph nodes. Ten case studies (57%) showed complete resolution of extra-CNS tumor burden. Median progression-free survival was 13 months following radiation. Four papers investigated incidence of abscopal effects in patients with metastatic melanoma to the brain who received immune checkpoint inhibitor therapy (n = 160); two papers found an abscopal effect in 35% and 52% of patients (n = 16, 21 respectively), and two papers found no evidence of abscopal effects (n = 61, 62). Conclusions Abscopal effects can occur following radiotherapy in patients with brain or spine metastases and is thought to be a result of increased anti-tumor immunity. The potential for immune checkpoint inhibitor therapy to be used in combination with radiotherapy to induce an abscopal effect is an area of active investigation.

Glioblastoma (GBM) is the most common and aggressive primary adult brain tumor, with an estimated annual incidence of 17 000 new cases in the United States. Current treatments for GBM include chemotherapy, surgical resection, radiation therapy, and antiangiogenic therapy. However, despite the various therapeutic options, the 5-year survival rate remains at a dismal 5%. Temozolomide (TMZ) is the first-line chemotherapy drug for GBM; however, poor TMZ response is one of the main contributors to the dismal prognosis. Long non-coding RNAs (lncRNAs) are nonprotein coding transcripts greater than 200 nucleotides that have been implicated to mediate various GBM pathologies, including chemoresistance. In this review, we aim to frame the TMZ response in GBM via exploration of the lncRNAs mediating three major mechanisms of TMZ resistance: (1) regulation of the DNA damage response, (2) maintenance of glioma stem cell identity, and (3) exploitation of hypoxia-associated responses.

INTRODUCTION: Successful endovascular management of aneurysmal subarachnoid hemorrhage (aSAH) requires timely access to significant resources. Prior studies suggest an association between time to treatment and patient outcome. Patients treated at safety- net hospitals are thought to be particularly vulnerable to disparities in access to interventions that require substantial technological resources. We hypothesize that patients treated at safety-net hospitals are at greater risk for delayed access to endovascular treatment. MATERIALS AND METHODS: Adults undergoing endovascular coiling procedures between 2002–2011 in the Nationwide Inpatient Sample were included. Hospitals in the quartile with the highest proportion of Medicaid or uninsured patients were defined as safety-net hospitals. A multivariable model including patient and hospital-level factors was constructed to permit analysis of delays in endovascular treatment (defined as time to treatment greater than 3 days). RESULTS: Analysis included 7,109 discharges of patients with aSAH undergoing endovascular coil embolization procedures from 2002–2011. The median time to coil embolization in all patients was 1 day; 10.1% of patients waited more than three days until treatment. In multivariable analysis, patients treated at safety-net hospitals were more likely to have a prolonged time to coil embolization (OR 1.32, p