Abstract Meningiomas are the most frequent primary intracranial tumors. Hence, they constitute a major share of diagnostic specimens in neuropathology practice. The 2021 WHO Classification of Central Nervous System Tumors (“CNS5”) has introduced the first molecular grading parameters for meningioma with oncogenic variants in the TERT promoter and homozygous deletion of CDKN2A/B as markers for CNS WHO grade 3. However, after the publication of the new classification volume, clarifications were requested, not only on novel but also on long-standing questions in meningioma grading that were beyond the scope of the WHO “blue book.” In addition, more recent research into possible new molecular grading parameters could not yet be implemented in the 2021 classification but constitutes a compelling body of literature. Hence, the consortium to inform molecular and practical approaches to CNS tumor taxonomy-not official WHO (cIMPACT-NOW) Steering Committee convened a working group to provide such clarification and assess the evidence of possible novel molecular criteria. As a result, this cIMPACT-NOW update provides guidance for more standardized morphological evaluation and interpretation, most prominently pertaining to brain invasion, identifies scenarios in which advanced molecular testing is recommended, proposes to assign CNS WHO grade 2 for cases with CNS WHO grade 1 morphology but chromosomal arm 1p deletion in combination with 22q deletion and/or NF2 oncogenic variants, and discusses areas in which the current evidence is not yet sufficient to result in new recommendations.
Suicidal ideation and attempts in brain tumor patients and survivors: A systematic review
Abstract Background Subsequent to a diagnosis of a brain tumor, psychological distress has been associated with negative effects on mental health as well as suicidality. The magnitude of such impact has been understudied in the literature. We conducted a systematic review to examine the impact of a brain tumor on suicidality (both ideation and attempts). Methods In accordance with the PRISMA guidelines, we searched for relevant peer-reviewed journal articles on PubMed, Scopus, and Web of Science databases from inception to October 20, 2022. Studies investigating suicide ideation and/or attempt among patients with brain tumors were included. Results Our search yielded 1,998 articles which were screened for eligibility. Seven studies consisting of 204,260 patients were included in the final review. Four studies comprising 203,906 patients (99.8%) reported elevated suicidal ideation and suicide attempt incidence compared with the general population. Prevalence of ideation and attempts ranged from 6.0% to 21.5% and 0.03% to 3.33%, respectively. Anxiety, depression, pain severity, physical impairment, glioblastoma diagnosis, male sex, and older age emerged as the primary risk factors associated with increased risk of suicidal ideation and attempts. Conclusion Suicidal ideation and attempts are increased in patients and survivors of brain tumors compared to the general population. Early identification of patients exhibiting these behaviors is crucial for providing timely psychiatric support in neuro-oncological settings to mitigate potential harm. Future research is required to understand pharmacological, neurobiological, and psychiatric mechanisms that predispose brain tumor patients to suicidality.
Radiographic Predictors of Occult Intracranial Involvement in Olfactory Neuroblastoma Patients
AbstractBackgroundTraditional management of olfactory neuroblastoma (ONB) includes margin‐negative resection with removal of cribriform plate, dura, and olfactory bulb, regardless of intracranial disease. This approach may be overtreating certain patients. Our investigation examines risk factors associated with occult intracranial disease to optimize therapeutic outcomes.MethodsThis retrospective, multi‐institutional cohort study examined clinical covariates associated with occult intracranial involvement. Patient demographics, staging, Hyam's grade, and pathologic involvement of dura, olfactory bulb/tract, and brain were collected. Diagnostic imaging was reviewed. Positive and negative predictive value (NPV) were estimated along with effect size estimates. Cox hazard regression examined associations with overall survival (OS) and disease‐free survival (DFS).ResultsA total of 224 subjects with new diagnoses of ONB (2005–2021) were identified. Skull base bone involvement on computed tomography (CT) had the highest NPV for pathologic dura (88.0%), olfactory bulb (88%), and brain involvement (97.3%). Hyam's grade category was significantly associated with dural involvement (φC = 0.26; 95% confidence interval [CI]: 0.16, 0.42). Subjects without radiologic skull base involvement (n = 66) had pathologic positivity of 12.1%. Within this subgroup, Hyam's grade was clinically significant for dural positivity (φ = 0.34; 95% CI: −0.12, 0.71) with 28.6% involvement in high grade tumors. Neither clinical nor pathologic positivity of intracranial structures were associated with significantly different OS or DFS.ConclusionsBoth CT and magnetic resonance imaging (MRI) had reasonably good NPV for involvement of dura and olfactory bulb. Higher Hyam's grade was associated with dural involvement. Patients with low‐grade tumors not involving the skull base may be suitable for avoiding skull base resection; however, further investigation is warranted.
A noncoding single-nucleotide polymorphism at 8q24 drives
IDH1
-mutant glioma formation
Establishing causal links between inherited polymorphisms and cancer risk is challenging. Here, we focus on the single-nucleotide polymorphism rs55705857, which confers a sixfold greater risk of isocitrate dehydrogenase ( IDH) –mutant low-grade glioma (LGG). We reveal that rs55705857 itself is the causal variant and is associated with molecular pathways that drive LGG. Mechanistically, we show that rs55705857 resides within a brain-specific enhancer, where the risk allele disrupts OCT2/4 binding, allowing increased interaction with the Myc promoter and increased Myc expression. Mutating the orthologous mouse rs55705857 locus accelerated tumor development in an Idh1 R132H -driven LGG mouse model from 472 to 172 days and increased penetrance from 30% to 75%. Our work reveals mechanisms of the heritable predisposition to lethal glioma in ~40% of LGG patients.
Radiation Therapy for Brain Metastases: ASCO Guideline Endorsement of ASTRO Guideline
PURPOSE American Society of Radiation Oncology (ASTRO) has developed a guideline on appropriate radiation therapy for brain metastases. ASCO has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations. METHODS “Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline” 2 was reviewed for developmental rigor by methodologists. An ASCO Endorsement Panel subsequently reviewed the content and the recommendations. RESULTS The ASCO Endorsement Panel determined that the recommendations from the ASTRO guideline, published May 6, 2022, are clear, thorough, and based upon the most relevant scientific evidence. ASCO endorses “Radiation Therapy for Brain Metastases: An ASTRO Clinical Practice Guideline.” 2 RECOMMENDATIONS Within the guideline, stereotactic radiosurgery (SRS) is recommended for patients with Eastern Cooperative Oncology Group performance status of 0-2 and up to four intact brain metastases, and conditionally recommended for patients with up to 10 intact brain metastases. The guideline provides detailed dosing and fractionation recommendations on the basis of the size of the metastases. For patients with resected brain metastases, radiation therapy (SRS or whole-brain radiation therapy [WBRT]) is recommended to improve intracranial disease control; if there are limited additional brain metastases, SRS is recommended over WBRT. For patients with favorable prognosis and brain metastases ineligible for surgery and/or SRS, WBRT is recommended with hippocampal avoidance where possible and the addition of memantine is recommended. For patients with brain metastases, limiting the single-fraction V 12Gy to brain tissue to ≤ 10 cm 3 is conditionally recommended. Additional information is available at www.asco.org/neurooncology-guidelines .
Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline
Abstract Purpose To provide guidance to clinicians regarding therapy for patients with brain metastases from solid tumors. Methods ASCO convened an Expert Panel and conducted a systematic review of the literature. Results Thirty-two randomized trials published in 2008 or later met eligibility criteria and form the primary evidentiary base. Recommendations Surgery is a reasonable option for patients with brain metastases. Patients with large tumors with mass effect are more likely to benefit than those with multiple brain metastases and/or uncontrolled systemic disease. Patients with symptomatic brain metastases should receive local therapy regardless of the systemic therapy used. For patients with asymptomatic brain metastases, local therapy should not be deferred unless deferral is specifically recommended in this guideline. The decision to defer local therapy should be based on a multidisciplinary discussion of the potential benefits and harms that the patient may experience. Several regimens were recommended for non–small-cell lung cancer, breast cancer, and melanoma. For patients with asymptomatic brain metastases and no systemic therapy options, stereotactic radiosurgery (SRS) alone should be offered to patients with one to four unresected brain metastases, excluding small-cell lung carcinoma. SRS alone to the surgical cavity should be offered to patients with one to two resected brain metastases. SRS, whole brain radiation therapy, or their combination are reasonable options for other patients. Memantine and hippocampal avoidance should be offered to patients who receive whole brain radiation therapy and have no hippocampal lesions and 4 months or more expected survival. Patients with asymptomatic brain metastases with either Karnofsky Performance Status ≤ 50 or Karnofsky Performance Status < 70 with no systemic therapy options do not derive benefit from radiation therapy. Additional information is available at www.asco.org/neurooncology-guidelines.
Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline
PURPOSE To provide guidance to clinicians regarding therapy for patients with brain metastases from solid tumors. METHODS ASCO convened an Expert Panel and conducted a systematic review of the literature. RESULTS Thirty-two randomized trials published in 2008 or later met eligibility criteria and form the primary evidentiary base. RECOMMENDATIONS Surgery is a reasonable option for patients with brain metastases. Patients with large tumors with mass effect are more likely to benefit than those with multiple brain metastases and/or uncontrolled systemic disease. Patients with symptomatic brain metastases should receive local therapy regardless of the systemic therapy used. For patients with asymptomatic brain metastases, local therapy should not be deferred unless deferral is specifically recommended in this guideline. The decision to defer local therapy should be based on a multidisciplinary discussion of the potential benefits and harms that the patient may experience. Several regimens were recommended for non–small-cell lung cancer, breast cancer, and melanoma. For patients with asymptomatic brain metastases and no systemic therapy options, stereotactic radiosurgery (SRS) alone should be offered to patients with one to four unresected brain metastases, excluding small-cell lung carcinoma. SRS alone to the surgical cavity should be offered to patients with one to two resected brain metastases. SRS, whole brain radiation therapy, or their combination are reasonable options for other patients. Memantine and hippocampal avoidance should be offered to patients who receive whole brain radiation therapy and have no hippocampal lesions and 4 months or more expected survival. Patients with asymptomatic brain metastases with either Karnofsky Performance Status ≤ 50 or Karnofsky Performance Status < 70 with no systemic therapy options do not derive benefit from radiation therapy. Additional information is available at www.asco.org/neurooncology-guidelines .
TMOD-18. DIRECT IN VIVO CRISPR SCREEN IDENTIFIES COOPERATING TUMOR SUPPRESSORS THAT DRIVE PROGRESSION OF IDH1-MUTANT LOW-GRADE GLIOMA TO AGGRESSIVE GLIOBLASTOMA
Abstract Low-grade glioma (LGG) are generally slowly growing brain cancers, that frequently undergo malignant progression to aggressive, secondary glioblastoma with a dismal prognosis. By combining genetically engineered Idh1-mutant mice with in vivo CRISPR gene editing we generated a mouse model faithfully recapitulating the founder mutations of LGG. Clonal activation of the neomorphic Idh1 R132H mutation cooperates with Trp53 and Atrx mutations to trigger development of brain tumors but only with ~30% penetrance and very long latency. To elucidate the molecular mechanisms underlying the malignant progression of IDH1-mutant LGG, we devised and deployed a direct in vivo CRISPR screen targeting genes commonly mutated in human IDH-mutant secondary glioblastoma. Stereotaxic delivery of a lentiviral sgRNA library targeting the mouse orthologs of these genes into the brain of Idh1 R132H ;Trp53;Atrx;Cas9 and control Idh1 wt ;Trp53;Atrx;Cas9 compound mutant mice resulted in rapid formation of tumors that recapitulate human Idh1-mutant glioblastoma. Deconvoluting the screen showed that PI3K pathway members Pten and Pik3ca as well as Notch1, Smarca4 and Fat1 are preferentially enriched in Idh1 R132H-tumors, while Rb1 and NF2 were enriched in Idh1 wt tumors. Co-mutation analysis further identified additional co-occurring driver combinations such as Bcor-Met, Olig2-Met, Olig2-Med12 or Bcor-Olig2. We validated the tumor suppressive function of Notch1 and Pten using conventional floxed knock-out alleles and found that Notch1 functions in a haploinsufficient manner. Interestingly, Idh1 R132H did not alter tumor latency or pathology in a high grade p53;Pten;Rb1 mutant background, indicating that the neomorphic IDH-mutations can drive low but not high grade glioma development. Our study provides a functional landscape of gliomagenesis suppressors in vivo.
EPCO-22. INHERITED POLYMORPHISM IN CHROMOSOME 8Q24 COOPERATES WITH MUTANT IDH1, Trp53 AND ATRX LOSS TO INDUCE LOW-GRADE GLIOMA
Abstract Establishing causal links between genetic polymorphisms and increased heritable risk of developing brain cancer is a major challenge. The non-coding single nucleotide polymorphism rs55705857 (A >G) is associated with a ~6-fold increased risk to develop IDH-mutant low-grade glioma (LGG). The rs55705857 G allele has a minor allele frequency of only ~5% in the general population but is found in ~40% of patients with IDH-mutant LGG and patients carrying risk-alleles are diagnosed on average 7-12 years earlier than those carrying non-risk A alleles. This makes rs55705857 one of the highest reported genetic associations with cancer, comparable with inherited BRCA1 gene mutations and the risk of developing breast cancer or other familial glioma genes such as NF1/2, CDKN2A or p53. To generate a LGG mouse model, we combined clonal activation of IDH1R132H with mutations of Trp53 and Atrx, which resulted in the development of LGG-like brain tumors in 25% of mice. Mutating the highly conserved, orthologous mouse rs55705857 locus to mimic the human risk allele dramatically accelerated tumor development from 463 to 172 days and increased penetrance to 75%. The resulting tumors exhibit elevated R-2-hydroxyglutarate levels, well-differentiated fibrillary neoplastic histology and metabolic rewiring, recapitulating histopathological and molecular hallmarks of human LGG. Mechanistically, we show that the rs55705857 locus resides within a brain-specific enhancer, which shows enhanced activity in IDH-mutant tumors. In addition, we found that the risk allele disrupts OCT2/4 binding, allowing increased interaction with the Myc promoter and increased Myc expression. The hyperactive chromatin status combined with the tissue specificity of this enhancer explains the cooperativity between mutant IDH and rs55705857 and why rs55705857 is associated specifically with IDH-mutant glioma, but not other cancers. Overall, we generated new LGG mouse models, which provide insights into the pathophysiology of this deadly disease and shed light into the heritable predisposition to LGG development.