Merrell, Ryan

The NCCN Guidelines for Central Nervous System (CNS) Cancers focus on management of the following adult CNS cancers: glioma (WHO grade 1, WHO grade 2–3 oligodendroglioma [1p19q codeleted, IDH- mutant], WHO grade 2–4 IDH- mutant astrocytoma, WHO grade 4 glioblastoma), intracranial and spinal ependymomas, medulloblastoma, limited and extensive brain metastases, leptomeningeal metastases, non–AIDS-related primary CNS lymphomas, metastatic spine tumors, meningiomas, and primary spinal cord tumors. The information contained in the algorithms and principles of management sections in the NCCN Guidelines for CNS Cancers are designed to help clinicians navigate through the complex management of patients with CNS tumors. Several important principles guide surgical management and treatment with radiotherapy and systemic therapy for adults with brain tumors. The NCCN CNS Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel’s most recent recommendations regarding molecular profiling of gliomas.

e13020 Background: Seizures are common in patients with glioma. Phenytoin, traditionally used for these patients, can be associated with intolerable side effects and potentially alters the metabolism of chemotherapeutic agents. Levetiracetam has more favorable pharmacokinetics facilitating ease of use with fewer side effects and is nonenzyme inducing. We compare seizure outcomes and side effects in patients with glioma treated with phenytoin and levetiracetam monotherapy. Methods: Retrospective analysis of consecutive patients with glioma. Subjects had at least one clinical seizure and had to be followed for 6 months. Seizure outcomes and side effects were compared between cohorts treated with phenytoin or levetiracetam. Seizure outcomes were measured by time to second seizure and seizure frequency. Results: 76 patients (34 female) with pathologically proven glioma and seizures were identified, 25 treated with phenytoin and 51 with levetiracetam. 64% had grade 4 astrocytoma. There was no difference in seizure outcome between the phenytoin and levetiracetam groups when comparing time to second seizure (p = 0.584), second seizure rates (p = 0.462), and average seizures per month (p = 0.776). When adjusting for age, gender, type of seizure, type of glioma, and dosage using univariate and multivariate models there were no differences between the treatment groups and none of these covariates were statistically significant for explaining the second seizure rates between treatment groups (all p values >0.05). The incidence of side effects in the levetiracetam group was 5.9% versus 20% in the phenytoin group (p = 0.106). Additionally, 36.0% of the patients in the phenytoin group had dose adjustments not related to breakthrough seizures compared to only 9.8% in the levetiracetam group (p = 0.010). Conclusions: In this study, glioma patients treated with levetiracetam had similar seizure control as patients treated with phenytoin. Patients treated with levetiracetam experienced fewer side effects and required fewer non seizure related dose adjustments than patients treated with phenytoin. Levetiracetam is a safe, effective, and preferred alternative for seizure management in patients with glioma. No significant financial relationships to disclose.

Abstract BACKGROUND: Incidence of glioma varies significantly by sex, and most glioma histologies occur with greater incidence in males. Previous analyses have examined the impact of estrogen exposure as a risk factor for these tumors, but have found results of varying significance and low effect size. There may be differences in effect of previously discovered risk alleles that contribute to sex differences. METHODS: Using data collected for three previous glioma GWAS in European-ancestry populations (MD Anderson Cancer Center, the San Francisco Adult Glioma Study, and the Glioma International Case Control Study) we assessed sex-specific effects for 14 previously identified and 13 newly identified glioma risk SNPs (27 total) overall and for glioblastoma (GBM) and non-GBM tumors separately. There were 3,892 male cases (59% GBM), 4,522 male controls, 2,500 female cases (52% GBM) and 4,940 female controls. Sex-specific odds ratios (ORM and ORF), 95% confidence intervals (95% CI) and p values (pM and pF) were generated using stratified logistic regression models. Data from each study were analyzed separately and combined using inverse variance weighted meta-analysis. Results were considered statistically significant at p<6.2x10-4. RESULTS: In GBM, rs11979158 (7p11.2, pM=1.01x10-10, ORM=1.43 [95% CI: 1.28-1.59]; pF=3.43x10-3, ORF=1.22 [95% CI: 1.07-1.39]) and rs2562152 (16p13.3, pM=5.59x10-4, ORM=1.23 [95% CI: 1.09-1.39]; pF=1.22x10-1, ORF=1.12 [95% CI: 0.97-1.29]) had significant effect in males only. In non-GBM gliomas, rs12076373 (1q44, pM=3.56x10-7, ORM=1.41, 95% CI: 1.23-1.61; pF=1.76x10-2, ORF=1.20, 95% CI: 1.03-1.38), rs11979158 (7p11.2, pM=1.77x10-5, ORM=1.32 [95% CI: 1.16-1.49]; pF=2.73x10-1, ORF=1.08 [95% CI: 0.94-1.24]), and rs3751667 (16p13.3, pM=9.44x10-7, ORM=1.30 [95% CI: 1.17-1.44]; pF=5.18x10-2, ORF=1.13 [95% CI: 1.00-1.28]) had significant effect in males only. Effect size for rs55705857 (8q24.21) varied significantly by sex, with ORM=2.63 (95% CI: 2.24-3.09, pM=4.42x10-32), as compared to ORF=3.95 (95% CI: 3.28-4.76, pF=1.82x10-47). A sensitivity analysis was performed due to allele frequency heterogeneity by study and results did not change. CONCLUSIONS: Sex differences and other demographic differences in cancer susceptibility can provide important clues to etiology, and these differences can be leveraged for discovery in genetic association studies. Significant differences in effect size may suggest variation in genetic effect of risk alleles or in unidentified risk factors that vary in prevalence or effect by sex. There may also be differences in the distribution of molecular subtypes within each histology by sex. Further investigation using an agnostic approach may further elucidate the relationship between effect of risk alleles and sex. Citation Format: Quinn T. Ostrom, Ben Kinnersley, Margaret Wrensch, Jeanette E. Eckel-Passow, Georgina Armstrong, Terri Rice, Yanwen Chen, John Wiencke, Lucie McCoy, Helen Hansen, Christopher Amos, Jonine L. Bernstein, Elizabeth B. Claus, Dora Il'yasova, Christoffer Johansen, Daniel Lachance, Rose Lai, Ching C. Lau, Ryan T. Merrell, Sara H. Olson, Siegal Sadetzki, Joellen Schildkraut, Sanjay Shete, Richard S. Houlston, Robert B. Jenkins, Beatrice Melin, Melissa Bondy, Jill S. Barnholtz-Sloan. Estimating sex-specific effects of genetic loci associated with glioma risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1315. doi:10.1158/1538-7445.AM2017-1315

Object Second-generation antiepileptic drugs (AEDs) are increasingly used in the care of patients with glioma. There is little data on how this practice compares with the use of traditional AEDs in this population. This noninferiority analysis compares seizure outcomes and side effects in patients with glioma treated with phenytoin and levetiracetam monotherapy. Methods The authors retrospectively reviewed the records of 500 consecutive patients with glioma who were treated in clinical trials from 2001 to 2008 at 3 Mayo Clinic campuses. To be eligible for the study, these patients had to have had at least 1 clinical seizure and to have undergone follow-up for at least 6 months. Seizure outcomes, defined by the occurrence of a second seizure, time to second seizure, and seizure frequency, along with AED side effects, were compared between cohorts treated with phenytoin or levetiracetam Results Seventy-six patients were identified, 25 treated with phenytoin and 51 with levetiracetam. Sixty-four percent of the patients had a Grade 4 astrocytoma. There was no difference in seizure outcome between the phenytoin and levetiracetam groups when comparing time to second seizure (p = 0.584), second seizure rates (p = 0.561), and average seizures per month (p = 0.776). When adjusting for age, sex, type of seizure, type of glioma, and dosage using univariate and multivariate models, there were no differences between the treatment groups and none of these covariates were statistically significant for explaining the second seizure rates between treatment groups (all p values > 0.05). The incidence of side effects in the levetiracetam group was 6% versus 20% in the phenytoin group (p = 0.106). Additionally, 36% of the patients in the phenytoin group had dose adjustments unrelated to breakthrough seizures compared with only 10% in the levetiracetam group (p = 0.010) Conclusions In this study, patients with glioma treated with levetiracetam and phenytoin had similar seizure control. Patients treated with levetiracetam experienced fewer side effects and required fewer nonseizure-related dose adjustments than patients treated with phenytoin. Levetiracetam is a safe, effective, and preferred alternative for seizure management in patients with glioma.