Corticosteroid use endpoints in neuro-oncology: Response Assessment in Neuro-Oncology Working Group.

Background: Corticosteroids are the mainstay of treatment for peritumor edema but are often associated with significant side effects. Therapies that can reduce corticosteroid use would potentially be of significant benefit to patients. However, currently there are no standardized endpoints evaluating corticosteroid use in neuro-oncology clinical trials. Methods: The Response Assessment in Neuro-Oncology (RANO) Working Group has developed consensus recommendations for endpoints evaluating corticosteroid use in clinical trials in both adults and children with brain tumors. Results: Responders are defined as patients with a 50% reduction in total daily corticosteroid dose compared with baseline or reduction of the total daily dose to ≤2 mg of dexamethasone (or equivalent dose of other corticosteroid); baseline dose must be at least 4 mg of dexamethasone daily (or equivalent dose of other corticosteroids) for at least one week. Patients must have stable or improved Neurologic Assessment in Neuro-Oncology (NANO) score or Karnofsky performance status score or Eastern Cooperative Oncology Group (ECOG) (Lansky score for children age <16 y), and an improved score on a relevant clinical outcome assessment tool. These criteria must be sustained for at least 4 weeks after baseline assessment to be considered a response, and are confirmed 4 weeks after that (ie, 8 wk after baseline assessment) to be considered a sustained response. Conclusions: This RANO proposal for corticosteroid use endpoints in neuro-oncology clinical trials may need to be refined and will require prospective validation in clinical studies.

Response assessment in medulloblastoma and leptomeningeal seeding tumors: recommendations from the Response Assessment in Pediatric Neuro-Oncology committee.

Lack of standard response criteria in clinical trials for medulloblastoma and other seeding tumors complicates assessment of therapeutic efficacy and comparisons across studies. An international working group was established to develop consensus recommendations for response assessment. The aim is that these recommendations be prospectively evaluated in clinical trials, with the goal of achieving more reliable risk stratification and uniformity across clinical trials. Current practices and literature review were performed to identify major confounding issues and justify subsequently developed recommendations; in areas lacking scientific investigations, recommendations were based on experience of committee members and consensus was reached after discussion. Recommendations apply to both adult and pediatric patients with medulloblastoma and other seeding tumors. Response should be assessed using MR imaging (brain and spine), CSF cytology, and neurologic examination. Clinical imaging standards with minimum mandatory sequence acquisition that optimizes detection of leptomeningeal metastases are defined. We recommend central review prior to inclusion in treatment cohorts to ensure appropriate risk stratification and cohort inclusion. Consensus recommendations and response definitions for patients with medulloblastomas and other seeding tumors have been established; as with other Response Assessment in Neuro-Oncology recommendations, these need to now be prospectively validated in clinical trials.

Response Assessment in Neuro-Oncology working group and European Association for Neuro-Oncology recommendations for the clinical use of PET imaging in gliomas.

This guideline provides recommendations for the use of PET imaging in gliomas. The review examines established clinical benefit in glioma patients of PET using glucose ((18)F-FDG) and amino acid tracers ((11)C-MET, (18)F-FET, and (18)F-FDOPA). An increasing number of studies have been published on PET imaging in the setting of diagnosis, biopsy, and resection as well radiotherapy planning, treatment monitoring, and response assessment. Recommendations are based on evidence generated from studies which validated PET findings by histology or clinical course. This guideline emphasizes the clinical value of PET imaging with superiority of amino acid PET over glucose PET and provides a framework for the use of PET to assist in the management of patients with gliomas.

Updated response assessment criteria for high-grade gliomas: response assessment in neuro-oncology working group.

Currently, the most widely used criteria for assessing response to therapy in high-grade gliomas are based on two-dimensional tumor measurements on computed tomography (CT) or magnetic resonance imaging (MRI), in conjunction with clinical assessment and corticosteroid dose (the Macdonald Criteria). It is increasingly apparent that there are significant limitations to these criteria, which only address the contrast-enhancing component of the tumor. For example, chemoradiotherapy for newly diagnosed glioblastomas results in transient increase in tumor enhancement (pseudoprogression) in 20% to 30% of patients, which is difficult to differentiate from true tumor progression. Antiangiogenic agents produce high radiographic response rates, as defined by a rapid decrease in contrast enhancement on CT/MRI that occurs within days of initiation of treatment and that is partly a result of reduced vascular permeability to contrast agents rather than a true antitumor effect. In addition, a subset of patients treated with antiangiogenic agents develop tumor recurrence characterized by an increase in the nonenhancing component depicted on T2-weighted/fluid-attenuated inversion recovery sequences. The recognition that contrast enhancement is nonspecific and may not always be a true surrogate of tumor response and the need to account for the nonenhancing component of the tumor mandate that new criteria be developed and validated to permit accurate assessment of the efficacy of novel therapies. The Response Assessment in Neuro-Oncology Working Group is an international effort to develop new standardized response criteria for clinical trials in brain tumors. In this proposal, we present the recommendations for updated response criteria for high-grade gliomas.

Antiangiogenic therapy for high-grade gliomas.

BACKGROUND: Gliomas and in particular high-grade gliomas (HGG) demonstrate when compared to other non-neural solid cancers amongst the highest levels of tumor angiogenesis (the formation of new blood vessels from pre-existing vasculature). METHODS: Angiogenesis is a common theme in cancer biology and reflects the requirement of a vascular network to support continued uncontrolled cancer growth. Early recognition of this paradigm suggested a potential and novel cancer treatment target that led to the discovery and implementation of antiangiogenic therapies. Two basic strategies of cancer antiangiogenic therapy have emerged, one targeting vascular endothelial growth factor, VEGF (growth factor ligand-based antagonists) and the second targeting the vascular endothelial growth factor receptor, VEGFR (receptor-based antagonists, small molecule tyrosine kinase inhibitors). Emerging literature suggests efficacy of antiangiogenic therapy for recurrent HGG. RESULTS: Notwithstanding the limited literature regarding the treatment of recurrent HGG with antiangiogenic therapy (predominantly ligand-based and administered in conjunction with cytotoxic chemotherapy), this therapy has become the de facto standard of care for many. Response rates vary from 30-60% and 6-month progression free survival varies from 25-50%. Problematic however are new antiangiogenic class side effects (hypertension, fatigue, proteinuria, intratumoral hemorrhage, arterial thrombosis and wound dehiscence), timing in relationship to surgery, measurements of response, lack of established dose response relationships and pharmacoeconomics and a possible change in tumor biology. CONCLUSIONS: Ligand-based antiangiogenic therapy (in particular bevacizumab) is a compelling new targeted therapy for HGG and will continue to emerge as an important novel anti-glioma therapy. Further studies are required to define the population of patients with HGG in whom this therapy is of benefit, identify the optimal dose and schedule, better characterize the value of co-administered (cytotoxic and targeted) therapies and establish validated response measures.