Histopathological correlation of brain tumor recurrence vs. radiation effect post-radiosurgery as detected by MRI contrast clearance analysis: a validation study.

PURPOSE: The differentiation between adverse radiation effects (ARE) and tumor recurrence or progression (TRP) is a major decision-making point in the follow-up of patients with brain tumors. The advent of immunotherapy, targeted therapy and radiosurgery has made this distinction difficult to achieve in several clinical situations. Contrast clearance analysis (CCA) is a useful technique that can inform clinical decisions but has so far only been histologically validated in the context of high-grade gliomas. METHODS: This is a series of 7 patients, treated between 2018 and 2023, for various brain pathologies including brain metastasis, atypical meningioma, and high-grade glioma. MRI with contrast clearance analysis was used to inform clinical decisions and patients underwent surgical resection as indicated. The histopathology findings were compared with the CCA findings in all cases. RESULTS: All seven patients had been treated with gamma knife radiosurgery and were followed up with periodic MR imaging. All patients underwent CCA when the necessity to distinguish tumor recurrence from radiation necrosis arose, and subsequently underwent surgery as indicated. Concordance of CCA findings with histological findings was found in all cases (100%). CONCLUSIONS: Based on prior studies on GBM and the surgical findings in our series, delayed contrast extravasation MRI findings correlate well with histopathology across a wide spectrum of brain tumor pathologies. CCA can provide a quick diagnosis and have a direct impact on patients' treatment and outcomes.

Bevacizumab and gamma knife radiosurgery for first-recurrence glioblastoma.

INTRODUCTION: Glioblastoma (GBM) is the most common central nervous system malignancy in adults. Despite decades of developments in surgical management, radiation treatment, chemotherapy, and tumor treating field therapy, GBM remains an ultimately fatal disease. There is currently no definitive standard of care for patients with recurrent glioblastoma (rGBM) following failure of initial management. OBJECTIVE: In this retrospective cohort study, we set out to examine the relative effects of bevacizumab and Gamma Knife radiosurgery on progression-free survival (PFS) and overall survival (OS) in patients with GBM at first-recurrence. METHODS: We conducted a retrospective review of all patients with rGBM who underwent treatment with bevacizumab and/or Gamma Knife radiosurgery at Roswell Park Comprehensive Cancer Center between 2012 and 2022. Mean PFS and OS were determined for each of our three treatment groups: Bevacizumab Only, Bevacizumab Plus Gamma Knife, and Gamma Knife Only. RESULTS: Patients in the combined treatment group demonstrated longer post-recurrence median PFS (7.7 months) and median OS (11.5 months) compared to glioblastoma patients previously reported in the literature, and showed improvements in total PFS (p=0.015), total OS (p=0.0050), post-recurrence PFS (p=0.018), and post-recurrence OS (p=0.0082) compared to patients who received either bevacizumab or Gamma Knife as monotherapy. CONCLUSION: This study demonstrates that the combined use of bevacizumab with concurrent stereotactic radiosurgery can have improve survival in patients with rGBM.

Phase IIa Study of SurVaxM Plus Adjuvant Temozolomide for Newly Diagnosed Glioblastoma.

PURPOSE: Despite intensive treatment with surgery, radiation therapy, temozolomide (TMZ) chemotherapy, and tumor-treating fields, mortality of newly diagnosed glioblastoma (nGBM) remains very high. SurVaxM is a peptide vaccine conjugate that has been shown to activate the immune system against its target molecule survivin, which is highly expressed by glioblastoma cells. We conducted a phase IIa, open-label, multicenter trial evaluating the safety, immunologic effects, and survival of patients with nGBM receiving SurVaxM plus adjuvant TMZ following surgery and chemoradiation (ClinicalTrials.gov identifier: NCT02455557). METHODS: Sixty-four patients with resected nGBM were enrolled including 38 men and 26 women, in the age range of 20-82 years. Following craniotomy and fractionated radiation therapy with concurrent TMZ, patients received four doses of SurVaxM (500 µg once every 2 weeks) in Montanide ISA-51 plus sargramostim (granulocyte macrophage colony-stimulating factor) subcutaneously. Patients subsequently received adjuvant TMZ and maintenance SurVaxM concurrently until progression. Progression-free survival (PFS) and overall survival (OS) were reported. Immunologic responses to SurVaxM were assessed. RESULTS: SurVaxM plus TMZ was well tolerated with no serious adverse events attributable to SurVaxM. Of the 63 patients who were evaluable for outcome, 60 (95.2%) remained progression-free 6 months after diagnosis (prespecified primary end point). Median PFS was 11.4 months and median OS was 25.9 months measured from first dose of SurVaxM. SurVaxM produced survivin-specific CD8+ T cells and antibody/immunoglobulin G titers. Apparent clinical benefit of SurVaxM was observed in both methylated and unmethylated patients. CONCLUSION: SurVaxM appeared to be safe and well tolerated. The combination represents a promising therapy for nGBM. For patients with nGBM treated in this manner, PFS may be an acceptable surrogate for OS. A large randomized clinical trial of SurVaxM for nGBM is in progress.

Prospective prediction of clinical drug response in high-grade gliomas using an ex vivo 3D cell culture assay.

BACKGROUND: Clinical outcomes in high-grade glioma (HGG) have remained relatively unchanged over the last 3 decades with only modest increases in overall survival. Despite the validation of biomarkers to classify treatment response, most newly diagnosed (ND) patients receive the same treatment regimen. This study aimed to determine whether a prospective functional assay that provides a direct, live tumor cell-based drug response prediction specific for each patient could accurately predict clinical drug response prior to treatment. METHODS: A modified 3D cell culture assay was validated to establish baseline parameters including drug concentrations, timing, and reproducibility. Live tumor tissue from HGG patients were tested in the assay to establish response parameters. Clinical correlation was determined between prospective ex vivo response and clinical response in ND HGG patients enrolled in 3D-PREDICT (ClinicalTrials.gov Identifier: NCT03561207). Clinical case studies were examined for relapsed HGG patients enrolled on 3D-PREDICT, prospectively assayed for ex vivo drug response, and monitored for follow-up. RESULTS: Absent biomarker stratification, the test accurately predicted clinical response/nonresponse to temozolomide in 17/20 (85%, P = .007) ND patients within 7 days of their surgery, prior to treatment initiation. Test-predicted responders had a median overall survival post-surgery of 11.6 months compared to 5.9 months for test-predicted nonresponders (P = .0376). Case studies provided examples of the clinical utility of the assay predictions and their impact upon treatment decisions resulting in positive clinical outcomes. CONCLUSION: This study both validates the developed assay analytically and clinically and provides case studies of its implementation in clinical practice.

Sellar and Parasellar Pain Syndromes.

PURPOSE OF REVIEW: Sellar and parasellar lesions are numerous and varying in terms of their patholphysiology and physical and radiographic characteristics but often incite pain syndromes that are similar in semiology. The goal of this review was to familiarize the reader with a variety of sellar and parasellar lesions grouped together based on common clinical symptomatology, with a focus on important imaging characteristics that are often distinguishing features diagnostically. RECENT FINDINGS: In most cases, tissue acquisition via surgical resection or stereotactic biopsy are the mainstay for definitive diagnosis of sellar and parasellar lesions. With advances in MRI technology in particular in terms of resolution and the inclusion of new techniques including dynamic imaging with delayed contrast, imaging studies of lesions in the sellar and parasellar regions have become increasingly important for diagnostic purposes, with pituitary adenomas and schwannomas as prime examples. In the case of chordoid gliomas, molecular features of the tumor also help distinguish it from other disease processes similar in presentation, which have dramatic impacts on management. Advances in surgical approaches and radiation techniques offer more precise and targeted therapy to lesions in an area with increased risk of clinical morbidity given the high concentration of critically important structures that must be spared during treatment. Sellar and parasellar lesions have the potential to cause significant morbidity and mortality, highlighting the importance of clinical recognition of warning signs/symptoms, obtaining high-quality imaging studies in various modalities for diagnostic purposes, and prompt management which often involves a multimodal approach that includes surgical resection, radiation, and/or medical therapy. Future advanced imaging techniques will only improve presurgical diagnostic accuracy and lead to more prompt and efficient management.

Imaging of Pituitary and Parasellar Disorders.

PURPOSE OF REVIEW: This article reviews sellar and parasellar anatomy and the appearance of normal bone and soft tissue components on both CT and MRI. Pituitary gland structure and function are discussed with respect to hormone secretion, along with clinical syndromes caused by perturbations in hormone levels. Syndromes and specific diseases in the sellar and parasellar regions are discussed along with characteristic clinical features and imaging findings. RECENT FINDINGS: Bone and calcifications are best visualized with CT scans, while soft tissues are better defined using MRI. Some lesions have characteristic enhancement patterns with contrast; the presence of delayed contrast uptake further narrows the differential. SUMMARY: Lesions that commonly occur in the sellar and parasellar region include benign and malignant tumors, cysts, vascular pathology, inflammatory processes, and abscesses. Knowledge of sellar and parasellar anatomy and attention to the use and interpretation of various imaging modalities can be of great assistance to the clinician when formulating a differential diagnosis for lesions in this region.

Simulated bioprosthetic heart valve deformation under quasi-static loading.

For more than 40 years, the replacement of diseased natural heart valves with prosthetic devices has dramatically extended the quality and length of the lives of millions of patients worldwide. However, bioprosthetic heart valves (BHV) continue to fail due to structural failure resulting from poor tissue durability and faulty design. Clearly, an in-depth understanding of the biomechanical behavior of BHV at both the tissue and functional prosthesis levels is essential to improving BHV design and to reduce rates of failure. In this study, we simulated quasi-static BHV leaflet deformation under 40, 80, and 120 mm Hg quasi-static transvalvular pressures. A Fung-elastic material model was used that incorporated material parameters and axes derived from actual leaflet biaxial tests and measured leaflet collagen fiber structure. Rigorous experimental validation of predicted leaflet strain field was used to validate the model results. An overall maximum discrepancy of 2.36% strain between the finite element (FE) results and experiment measurements was obtained, indicating good agreement between computed and measured major principal strains. Parametric studies utilizing the material parameter set from one leaflet for all three leaflets resulted in substantial variations in leaflet stress and strain distributions. This result suggests that utilization of actual leaflet material properties is essential for accurate BHV FE simulations. The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV function and design.