A rare case of pituitary oncocytoma successfully treated with single-fraction stereotactic Gamma Knife surgery

Efficacy of Dabrafenib for three children with brainstem BRAF V600E positive ganglioglioma Abstract Purpose Children with unresectable brainstem-infiltrated ganglioglioma have poor progression-free survival when treated with conventional chemotherapy and radiation regimens. The BRAFV600E mutation occurs in a large number of gangliogliomas, making them amenable for targeted therapy using mutation-specific kinase inhibitors. However, limited data exists on the effectiveness and best treatment duration of these inhibitors in this tumor setting. Method Retrospective description of three cases of childhood brainstem ganglioglioma with BRAFV600E mutation treated in the long-term with Dabrafenib, a specific BRAFV600E kinase inhibitor. Results Dabrafenib resulted in rapid tumoral regression and significant and durable clinical and radiological improvement. However, all patients had rapid clinical and radiological relapse within days to weeks following treatment discontinuation but showed similar rapid and sustained therapeutic response when Dabrafenib was re-introduced. This targeted therapy has been well tolerated despite its long-term use of 4.8 to 5.5 years in the three patients. Conclusion Dabrafenib is effective and seemingly safe and well tolerated in our three patients. We observed sustained chemosensitivity even when re-introducing this kinase inhibitor after its discontinuation after 2 years of therapy. These cases indicate the need to re-evaluate the timing and means of Dabrafenib discontinuation in pediatric patients with BRAFV600E mutated gangliogliomas and better assess the future implications of its long-term use.

Prognostic assessment in patients with newly diagnosed small cell lung cancer brain metastases: results from a real-life cohort Abstract Purposes Brain metastases (BM) are a frequent complication in small cell lung cancer (SCLC), resulting in a reduced survival prognosis. Precise prognostic assessment is an important foundation for treatment decisions and clinical trial planning. Methods Patients with newly diagnosed SCLC BM were identified from the Vienna Brain Metastasis Registry and evaluated concerning prognostic factors. Results 489 patients (male 62.2%, female 37.8%; median age 61 years) were included. Neurological symptoms were present in 297/489 (60.7%) patients. A- to oligosymptomatic patients (5 vs. 9 months, p = 0.030) as well as patients with synchronous diagnosis of BM and primary tumor (5 vs. 9 months, p = 0.008) presented with improved overall survival (OS) prognosis. RPA (HR 1.66; 95% CI 1.44–1.91; p < 0.001), GPA (HR 1.65; p < 0.001), DS-GPA (HR 1.60; p < 0.001) and LabBM score (HR 1.69; p < 0.001) were statistically significantly associated with OS. In multivariate analysis, DS-GPA (HR 1.59; p < 0.001), neurological deficits (HR 1.26; p = 0.021) and LabBM score (HR 1.57; p < 0.001) presented with statistical independent association with OS. Conclusion A- to oligosymptomatic BM as well as synchronous diagnosis of SCLC and BM were associated with improved OS. Established prognostic scores could be validated in this large SCLC BM real-life cohort.

Pediatric and adult H3 K27M-mutant diffuse midline glioma treated with the selective DRD2 antagonist ONC201 Abstract Background H3 K27M-mutant diffuse midline glioma is a fatal malignancy with no proven medical therapies. The entity predominantly occurs in children and young adults. ONC201 is a small molecule selective antagonist of dopamine receptor D2/3 (DRD2/3) with an exceptional safety profile. Following up on a durable response in the first H3 K27M-mutant diffuse midline glioma patient who received ONC201 (NCT02525692), an expanded access program was initiated. Methods Patients with H3 K27M-mutant gliomas who received at least prior radiation were eligible. Patients with leptomeningeal spread were excluded. All patients received open-label ONC201 orally once every week. Safety, radiographic assessments, and overall survival were regularly assessed at least every 8 weeks by investigators. As of August 2018, a total of 18 patients with H3 K27M-mutant diffuse midline glioma or DIPG were enrolled to single patient expanded access ONC201 protocols. Among the 18 patients: seven adult (> 20 years old) and seven pediatric (< 20 years old) patients initiated ONC201 with recurrent disease and four pediatric patients initiated ONC201 following radiation, but prior to disease recurrence. Findings Among the 14 patients with recurrent disease prior to initiation of ONC201, median progression-free survival is 14 weeks and median overall survival is 17 weeks. Three adults among the 14 recurrent patients remain on treatment progression-free with a median follow up of 49.6 (range 41–76.1) weeks. Among the 4 pediatric patients who initiated adjuvant ONC201 following radiation, two DIPG patients remain progression-free for at least 53 and 81 weeks. Radiographic regressions, including a complete response, were reported by investigators in a subset of patients with thalamic and pontine gliomas, along with improvements in disease-associated neurological symptoms. Interpretation The clinical outcomes and radiographic responses in these patients provide the preliminary, and initial clinical proof-of-concept for targeting H3 K27M-mutant diffuse midline glioma with ONC201, regardless of age or location, providing rationale for robust clinical testing of the agent.

Impact of the American Tax Payer Relief Act on stereotactic radiosurgery utilization in the United States Abstract Introduction Single-fraction stereotactic radiosurgery (SRS) is delivered predominantly via two modalities: Gamma Knife, and linear accelerator (LINAC). Implementation of the American Tax Payer Relief Act (ATRA) in 2013 represented the first time limitations specifically targeting SRS reimbursement were introduced into federal law. The subsequent impact of the ATRA on SRS utilization in the United States (US) has yet to be examined. Methods The National Cancer Database from 2010–2016 identified brain metastases patients from non-small cell lung cancer throughout the US having undergone SRS. Utilization between GKRS and LINAC was assessed before (2010–2012), during (2013–2014) and after (2015–2016) ATRA implementation. Results In 2013, there was a substantial decrease of LINAC SRS in favor of GKRS in non-academic centers. Over the 3-year span immediately preceding ATRA implementation, 39% of all eligible SRS cases received LINAC. There was a modest decrease in LINAC utilization over the 2 years immediately following ATRA implementation (35%), followed by an increase over the next two years (40%). SRS modality showed differences over the three time periods (unadjusted, p = 0.043), primarily in non-academic centers (unadjusted, p = 0.003). Conclusions ATRA implementation in 2013 caused an initial spike in Gamma Knife SRS utilization, followed by a decline to rates similar to the years before implementation. These findings indicate that the ATRA provision mandating Medicare reduction of outpatient payment rates for Gamma Knife to be equivalent with those of LINAC SRS had a significant short-term impact on the radiosurgical treatment of metastatic brain disease throughout the US, serving as a reminder of the importance/impact of public policy on treatment modality utilization by physicians and hospitals.

The protein arginine methyltransferase PRMT5 confers therapeutic resistance to mTOR inhibition in glioblastoma Abstract Introduction Clinical trials directed at mechanistic target of rapamycin (mTOR) inhibition have yielded disappointing results in glioblastoma (GBM). A major mechanism of resistance involves the activation of a salvage pathway stimulating internal ribosome entry site (IRES)-mediated protein synthesis. PRMT5 activity has been implicated in the enhancement of IRES activity. Methods We analyzed the expression and activity of PRMT5 in response to mTOR inhibition in GBM cell lines and short-term patient cultures. To determine whether PRMT5 conferred resistance we used genetic and pharmacological approaches to ablate PRMT5 activity and assessed the effects on in vitro and in vivo sensitivity. Mutational analyses of the requisite IRES-trans-acting factor (ITAF), hnRNP A1 determined whether PRMT5-mediated methylation was necessary for ITAF RNA binding and IRES activity. Results PRMT5 activity is stimulated in response to mTOR inhibitors. Knockdown or treatment with a PRMT5 inhibitor blocked IRES activity and sensitizes GBM cells. Ectopic expression of non-methylatable hnRNP A1 mutants demonstrated that methylation of either arginine residues 218 or 225 was sufficient to maintain IRES binding and hnRNP A1-dependent cyclin D1 or c-MYC IRES activity, however a double R218K/R225K mutant was unable to do so. The PRMT5 inhibitor EPZ015666 displayed synergistic anti-GBM effects in vitro and in a xenograft mouse model in combination with PP242. Conclusions These results demonstrate that PRMT5 activity is stimulated upon mTOR inhibition in GBM. Our data further support a signaling cascade in which PRMT5-mediated methylation of hnRNP A1 promotes IRES RNA binding and activation of IRES-mediated protein synthesis and resultant mTOR inhibitor resistance.

Surgery for temporal glioblastoma: lobectomy outranks oncosurgical-based gross-total resection Abstract Objective Supra-total glioblastoma resection has gained growing attention with regard to superior long-term disease control. However, aggressive onco-surgical approaches—geared beyond conventional gross total resections (GTR)—are limited by the impairment of adjacent eloquent areas at risk that may entail severe postoperative functional morbidity. Against this backdrop we analyzed our institutional database with regard to potential survival benefits of anterior temporal lobectomy as a paradigm for supra-total resection in patients with precisely temporal-located, non-eloquent glioblastoma. Methods Between 2012 and 2017, 38 patients with isolated temporal glioblastoma underwent GTR or temporal lobectomy at the authors’ institution. Both groups of differing resection modalities were compared with regard to postoperative Karnofsky performance score (KPS), progression-free survival (PFS), and overall survival (OS). Results Patients with temporal lobectomy exhibited significantly superior median KPS at the 12 months follow-up compared to the GTR group (median KPS of 80 vs. 60, p = 0.04). Temporal lobectomy was associated with significantly prolonged PFS (p = 0.005) and OS (p = 0.002) coming up to 15 months (95% CI 9.7–22.1) and 23 months (95% CI 14.8–34.5) compared to 7 months (95% CI 3.3–8.3) and 11 months (95% CI 9.2–17.9) for the GTR group. Multivariate analysis revealed temporal lobectomy as the only predictor for both superior PFS (p = 0.037, OR 7.3, 95% CI 1.1–47.4) and OS (p = 0.04, OR 7.8, 95% CI 1.1–55.2). Conclusions These results strongly suggest temporal lobectomy as an aggressive supra-total resection policy to constitute the surgical modality of choice for isolated temporal-located glioblastoma.

Outcome of three-fraction gamma knife radiosurgery for brain metastases according to fractionation scheme: preliminary results Abstract Purpose The optimal interfraction intervals for fractionated radiosurgery has yet to be established. We investigated the outcome of fractionated gamma knife radiosurgery (FGKRS) for large brain metastases (BMs) according to different interfraction intervals. Methods Between September 2016 and May 2018, a total of 45 patients who underwent FGKRS for BMs were enrolled in this study. They were divided into two groups (standard fractionation over 3 consecutive days with a 24-h interfraction interval versus prolonged fractionation over 4 or 5 days with an interfraction interval of at least 48-h). BMs with ≥ 2 cm in maximum diameter or ≥ 5 cm3 in volume were included in analysis. Results Among 52 BMs treated with 3-fraction GKRS, 25 (48.1%) were treated with standard fractionation scheme, and 27 (51.9%) with prolonged fractionation scheme. The median follow-up period was 10.5 months (range 5–25). Local tumor control rates of the standard group were 88.9% at 6 months and 77.8% at 12 months, whereas those of the prolonged group were 100% at 6 and 12 months (p = 0.023, log-rank test). In multivariate analysis, fractionation scheme (hazard ratio [HR] 0.294, 95% CI 0.099–0.873; p = 0.027) and tumor volume (HR 0.200, 95% CI 0.051–0.781; p = 0.021) were revealed as the only significant factors affecting the local tumor control after 3-fraction GKRS. Conclusions Our preliminary tumor control results suggest a promising role of 3-fraction GKRS with an interfraction interval of at least 48-h. This fractionation regimen could be an effective and safe treatment option in the management of large BMs.

CBX3 promotes glioma U87 cell proliferation and predicts an unfavorable prognosis Abstract Background Chromobox protein homolog 3 (CBX3) is one of the heterochromatin protein 1 (HP1) family members. Among multiple cancers, it is usually overexpressed. However, the mechanism and function of CBX3 in glioma remain incompletely illustrated. Methods The expression level of CBX3 as well as its correlation with glioma are detected through TCGA and Oncomine database. The expressions of CBX3 mRNA and protein in glioma tissues and normal brain tissues have been identified by qRT-PCR and Western blot. The prognostic role of CBX3 has been assessed in a retrospective cohort study. Additionally, the correlation between CBX3 expression and the clinicopathological characteristics of glioma patients were also discussed. To better understand the role of CBX3 in glioma, a lentiviral vector expressing CBX3-shRNA and cyclin dependent kinase inhibitor 1A (CDKN1A) siRNA were established and transfected into the glioma U87 cells. Besides, the CBX3 and CDKN1A expression levels in glioma U87 cells after transfected with CBX3-shRNA were gauged by qRT-PCR and Western blot. CCK-8, colony formation and EdU assays have been applied to evaluate the influence of CBX3 on U87 cells proliferation, and flow cytometry has been applied to manage the changes in cell cycle and cell apoptosis after transfection with CBX3-shRNA. Xenograft tumors have been examined in vivo for the carcinogenic effects and prognostic value of CBX3 in glioma tissues. Results In the present study, CBX3 was demonstrated to be highly expressed in human glioma tissues, and high CBX3 expression predicted the dismal recurrence-free survival (RFS) and poor overall survival (OS) for glioma patients. High CBX3 expression was dependent on the tumor size, Karnofsky performance scale (KPS) score, WHO grade, recurrence and survival status. Moreover, CBX3 expression knockdown could remarkably suppress the proliferation and colony formation ability of U87 cells, which was achieved through blocking cell arrest at G0/G1 phase and inducing apoptosis. Additionally, our findings also suggested that, compared with shRNA-Ctrl transfection, the mRNA and protein expression levels of CDKN1A have been dramatically up-regulated in vitro after transfection with shRNA-CBX3. Consistent with the results of in vitro assays, the outcomes of xenograft assay and immunohistochemistry (IHC) also indicated that, the tumor growth and Ki-67 expression level were restrained in response to CBX3 inhibition, while the CDKN1A expression level in vivo was up-regulated. Down-regulation of CDKN1A expression partially restored the ability of cell proliferation in the U87 cells, which was inhibited by shRNA-CBX3 Conclusions In conclusion, results of the current research suggest that a high CBX3 expression level predicts the poor prognosis for glioma patients. CBX3 can stimulate the growth of glioma U87 cells through targeting CDKN1A and CBX3 may become a novel target in the clinical treatment for glioma.