Lachance, Daniel

Abstract Purpose Bevacizumab is an effective treatment for radiation necrosis; dose dependent radiographic and edema response data are lacking. Methods Multicenter, retrospective cohort study of adult patients with primary central nervous system tumors or brain metastases who received bevacizumab for radiation necrosis between June 2021 and July 2024. Patients were grouped by bevacizumab dose (7.5 mg/kg vs 10 mg/kg administered every three weeks). Primary outcome was edema response, assessed by a blinded neuro-oncologist. Secondary outcomes included contrast enhancing disease response, clinical response, adverse events, treatment discontinuation, and re-dosing for recurrent radiation necrosis. Analyses were performed with and without adjustment for tumor type. Results 104 patients were included (7.5 mg/kg, n = 53; 10 mg/kg, n = 51). Edema response differed between dosing groups in unadjusted analyses (p = 0.032), favoring the 7.5 mg/kg cohort; however, this association was attenuated after adjustment for tumor type. Contrast enhancing disease response did not differ between groups in either unadjusted or adjusted analyses (p = 0.43). Clinical response was higher in the 7.5 mg/kg group (65.2% vs 37.8%, p = 0.013). Tumor type differed significantly between cohorts (p < 0.001), with more primary CNS tumors in the 10 mg/kg group. Rates of adverse events, treatment discontinuation, and re-dosing were similar. Conclusions While lower-dose bevacizumab was associated with greater edema reduction in unadjusted analyses, this effect was attenuated after accounting for tumor type. Importantly, 7.5 mg/kg dosing appeared sufficient for achieving edema control and contrast enhancing disease response. These findings support an individualized approach to bevacizumab dosing in radiation necrosis and highlight the need for prospective, tumor-stratified studies.

Abstract Background: Glioma diagnosed during pregnancy and pregnancy following glioma treatment present complex management challenges. The safety of glioma treatment during pregnancy is not well established. The ability to counsel patients on timing of conception after treatment remains limited. The aim of this study was to review our institution’s experience with glioma during and before pregnancy. Methods: In this single-institution study, we retrospectively identified patients diagnosed with glioma during or prior to pregnancy and reviewed treatment course and maternal and neonatal outcomes. Results: Twenty-one female patients were included in our study. Glioma diagnoses included 12 high-grade tumors and 9 low-grade tumors. Cohort A consisted of 8 patients who presented with glioma during pregnancy, of which, 7 underwent glioma treatment during pregnancy. All pregnancies in cohort A were without significant maternal complications and resulted in delivery of a healthy neonate. Cohort B consisted of 13 patients who experienced pregnancy after a prior diagnosis of glioma, totaling 23 pregnancies. Antepartum course was complicated by seizure in three pregnancies. Functionally inconsequential anatomic abnormalities in childhood offspring of cohort B occurred in 5 (27.8%) of the pregnancies. Four of the offspring with anatomic abnormalities had exposure to TMZ prior to conception. Conclusions: In this retrospective series, diagnosis of glioma before or during pregnancy was associated with generally favorable maternal, fetal and childhood outcomes. We observed a higher-than-expected rate of anatomic abnormalities in the post-diagnosis cohort, though none carried meaningful functional consequences. These findings add to the limited literature exploring maternal and fetal outcomes in patients with glioma.

AbstractPleomorphic xanthoastrocytoma (PXA) is a rare localized glioma characterized by frequent BRAF V600E mutation and CDKN2A/B deletion. We explored the association of copy‐number variants (CNVs) with BRAF mutations, tumor grade, and patient survival in a cohort of 41 PXA patients using OncoScan chromosomal microarray. Primary resection specimens were available in 38 cases, including 24 PXA and 14 anaplastic PXA (A‐PXA), 23 BRAF V600E mutant tumors (61%). CNVs were identified in all cases and most frequently involved chromosome 9 with homozygous CDKN2A/B deletion (n = 33, 87%), a higher proportion than previously detected by comparative genomic hybridization (50%–60%) (37). CDKN2A/B deletion was present in similar proportion of PXA (83%), A‐PXA (93%), BRAF V600E (87%), and wild‐type (87%) tumors. Whole chromosome gains/losses were frequent, including gains +7 (n = 15), +2 (n = 11), +5 (n = 10), +21 (n = 10), +20 (n = 9), +12 (n = 8), +15 (n = 8), and losses −22 (n = 11), −14 (n = 7), −13 (n = 5). Losses and copy‐neutral loss of heterozygosity were significantly more common in A‐PXA, involving chromosomes 22 (P = 0.009) and 14 (P = 0.03). Amplification of 8p and 12q was identified in a single tumor. Histologic grade was a robust predictor of overall survival (P = 0.003), while other copy‐number changes, including CDKN2A/B deletion, did not show significant association with survival. Distinct histologic patterns of anaplasia included increased mitotic activity in an otherwise classic PXA or associated with small cell, fibrillary, or epithelioid morphology, with loss of SMARCB1 expression in one case. In 10 cases, matched specimens were compared, including A‐PXA with areas of distinct low‐ and high‐grade morphology (n = 2), matched primary/tumor recurrence (n = 7), or both (n = 1). Copy‐number changes on recurrence/anaplastic transformation were complex and highly variable, from nearly identical profiles to numerous copy‐number changes. Overall, we confirm CDKN2A/B deletion as key a feature of PXA not associated with tumor grade or BRAF mutation, but central to the underlying genetics of PXA.

AbstractVaricella zoster virus (VZV) is a neurotropic α‐herpesvirus that causes chickenpox and establishes life‐long latency in the cranial nerve and dorsal root ganglia of the host. To date, VZV is the only virus consistently reported to have an inverse association with glioma. The Glioma International Case‐Control Study (GICC) is a large, multisite consortium with data on 4533 cases and 4171 controls collected across five countries. Here, we utilized the GICC data to confirm the previously reported associations between history of chickenpox and glioma risk in one of the largest studies to date on this topic. Using two‐stage random‐effects restricted maximum likelihood modeling, we found that a positive history of chickenpox was associated with a 21% lower glioma risk, adjusting for age and sex (95% confidence intervals (CI): 0.65–0.96). Furthermore, the protective effect of chickenpox was stronger for high‐grade gliomas. Our study provides additional evidence that the observed protective effect of chickenpox against glioma is unlikely to be coincidental. Future studies, including meta‐analyses of the literature and investigations of the potential biological mechanism, are warranted.

Abstract Background: Several previous studies have found inverse associations between glioma susceptibility and a history of allergies or other atopic conditions. Some evidence indicates that respiratory allergies are likely to be particularly relevant with regard to glioma risk. Using data from the Glioma International Case-Control Study (GICC), we examined the effects of respiratory allergies and other atopic conditions on glioma risk. Methods: The GICC contains detailed information on history of atopic conditions for 4,533 cases and 4,171 controls, recruited from 14 study sites across five countries. Using two-stage random-effects restricted maximum likelihood modeling to calculate meta-analysis ORs, we examined the associations between glioma and allergy status, respiratory allergy status, asthma, and eczema. Results: Having a history of respiratory allergies was associated with an approximately 30% lower glioma risk, compared with not having respiratory allergies (mOR, 0.72; 95% confidence interval, 0.58–0.90). This association was similar when restricting to high-grade glioma cases. Asthma and eczema were also significantly protective against glioma. Conclusion: A substantial amount of data on the inverse association between atopic conditions and glioma has accumulated, and findings from the GICC study further strengthen the existing evidence that the relationship between atopy and glioma is unlikely to be coincidental. Impact: As the literature approaches a consensus on the impact of allergies in glioma risk, future research can begin to shift focus to what the underlying biologic mechanism behind this association may be, which could, in turn, yield new opportunities for immunotherapy or cancer prevention. Cancer Epidemiol Biomarkers Prev; 25(2); 282–90. ©2016 AACR.