Toward digital histopathological assessment in surgery for central nervous system tumors using stimulated Raman histology.

OBJECTIVE: Intraoperative neuropathological assessment with conventional frozen sections supports the neurosurgeon in optimizing the surgical strategy. However, preparation and review of frozen sections can take as long as 45 minutes. Stimulated Raman histology (SRH) was introduced as a novel technique to provide rapid high-resolution digital images of unprocessed tissue samples directly in the operating room that are comparable to conventional histopathological images. Additionally, SRH images are simultaneously and easily accessible for neuropathological judgment. Recently, the first study showed promising results regarding the accuracy and feasibility of SRH compared with conventional histopathology. Thus, the aim of this study was to compare SRH with conventional H&E images and frozen sections in a large cohort of patients with different suspected central nervous system (CNS) tumors. METHODS: The authors included patients who underwent resection or stereotactic biopsy of suspected CNS neoplasm, including brain and spinal tumors. Intraoperatively, tissue samples were safely collected and SRH analysis was performed directly in the operating room. To enable optimal comparison of SRH with H&E images and frozen sections, the authors created a digital databank that included images obtained with all 3 imaging modalities. Subsequently, 2 neuropathologists investigated the diagnostic accuracy, tumor cellularity, and presence of diagnostic histopathological characteristics (score 0 [not present] through 3 [excellent]) determined with SRH images and compared these data to those of H&E images and frozen sections, if available. RESULTS: In total, 94 patients with various suspected CNS tumors were included, and the application of SRH directly in the operating room was feasible in all cases. The diagnostic accuracy based on SRH images was 99% when compared with the final histopathological diagnosis based on H&E images. Additionally, the same histopathological diagnosis was established in all SRH images (100%) when compared with that of the corresponding frozen sections. Moreover, the authors found a statistically significant correlation in tumor cellularity between SRH images and corresponding H&E images (p < 0.0005 and R = 0.867, Pearson correlation coefficient). Finally, excellent (score 3) or good (2) accordance between diagnostic histopathological characteristics and H&E images was present in 95% of cases. CONCLUSIONS: The results of this retrospective analysis demonstrate the near-perfect diagnostic accuracy and capability of visualizing relevant histopathological characteristics with SRH compared with conventional H&E staining and frozen sections. Therefore, digital SRH histopathology seems especially useful for rapid intraoperative investigation to confirm the presence of diagnostic tumor tissue and the precise tumor entity, as well as to rapidly analyze multiple tissue biopsies from the suspected tumor margin. A real-time analysis comparing SRH images and conventional histological images at the time of surgery should be performed as the next step in future studies.

MRI Response Assessment in Glioblastoma Patients Treated with Dendritic-Cell-Based Immunotherapy.

Introduction: In this post hoc analysis we compared various response-assessment criteria in newly diagnosed glioblastoma (GB) patients treated with tumor lysate-charged autologous dendritic cells (Audencel) and determined the differences in prediction of progression-free survival (PFS) and overall survival (OS). Methods: 76 patients enrolled in a multicenter phase II trial receiving standard of care (SOC, n = 40) or SOC + Audencel vaccine (n = 36) were included. MRI scans were evaluated using MacDonald, RANO, Vol-RANO, mRANO, Vol-mRANO and iRANO criteria. Tumor volumes (T1 contrast-enhancing as well as T2/FLAIR volumes) were calculated by semiautomatic segmentation. The Kruskal-Wallis-test was used to detect differences in PFS among the assessment criteria; for correlation analysis the Spearman test was used. Results: There was a significant difference in median PFS between mRANO (8.6 months) and Vol-mRANO (8.6 months) compared to MacDonald (4.0 months), RANO (4.2 months) and Vol-RANO (5.4 months). For the vaccination arm, median PFS by iRANO was 6.2 months. There was no difference in PFS between SOC and SOC + Audencel. The best correlation between PFS/OS was detected for mRANO (r = 0.65) and Vol-mRANO (r = 0.69, each p < 0.001). A total of 16/76 patients developed a pure T2/FLAIR progressing disease, and 4/36 patients treated with Audencel developed pseudoprogression. Conclusion: When comparing different response-assessment criteria in GB patients treated with dendritic cell-based immunotherapy, the best correlation between PFS and OS was observed for mRANO and Vol-mRANO. Interestingly, iRANO was not superior for predicting OS in patients treated with Audencel.

Assessment of Central Nervous System Lymphoma Based on CXCR4 Expression In Vivo Using 68Ga-Pentixafor PET/MRI.

PURPOSE OF THE REPORT: F-FDG PET is limited for assessment of central nervous system lymphoma (CNSL) due to physiologic tracer accumulation in the brain. We prospectively evaluated the novel PET tracer Ga-pentixafor, which targets the C-X-C chemokine receptor 4 (CXCR4), for lesion visualization and response assessment of CNSL. MATERIALS AND METHODS: Seven CNSL patients underwent Ga-pentixafor PET/MRI with contrast enhancement (CE-MRI) and diffusion-weighted sequences. The accuracy of Ga-pentixafor PET for CNSL lesion detection relative to the CE-MRI reference standard was determined. Standardized uptake values (SUVmean and SUVmax), PET-based (PTV) and MRI-based (VOLMRI) tumor volumes, and apparent diffusion coefficients (ADCs) were assessed, and correlation coefficients were calculated. Three SUVmax thresholds (41%, 50%, and 70%) were evaluated for PTV definitions (PTV41%, PTV50%, and PTV70%) and tested against VOLMRI using paired sample t tests. RESULTS: Twelve Ga-pentixafor PET/MRI examinations (including 5 follow-up scans) of 7 patients were evaluated. Ga-pentixafor PET demonstrated 18 lesions, all of which were confirmed by CE-MRI; there were no false-positive lesions on PET (accuracy, 100%). PTV41% showed the highest concordance with lesion morphology, with no significant difference compared with VOLMRI (mean difference, -0.24 cm; P = 0.45). The correlation between ADCmean and SUVmean41% (r = 0.68) was moderate. Changes in PTV41% on follow-up PET/MRI showed the same trend as VOLMRI changes, including progression of 1 lesion each in patient 1 (+456.0% PTV41% and +350.8% VOLMRI) and patient 3 (+110.4% PTV41% and +85.1% VOLMRI). CONCLUSIONS: Ga-pentixafor PET may be feasible for assessment and follow-up of CNSL. Future studies need to focus on testing its clinical value to distinguish between glioma and CNSL, and between radiation-induced inflammation and viable residual tumor.

Prognostic assessment in patients with newly diagnosed small cell lung cancer brain metastases: results from a real-life cohort.

PURPOSES: Brain metastases (BM) are a frequent complication in small cell lung cancer (SCLC), resulting in a reduced survival prognosis. Precise prognostic assessment is an important foundation for treatment decisions and clinical trial planning. METHODS: Patients with newly diagnosed SCLC BM were identified from the Vienna Brain Metastasis Registry and evaluated concerning prognostic factors. RESULTS: 489 patients (male 62.2%, female 37.8%; median age 61 years) were included. Neurological symptoms were present in 297/489 (60.7%) patients. A- to oligosymptomatic patients (5 vs. 9 months, p = 0.030) as well as patients with synchronous diagnosis of BM and primary tumor (5 vs. 9 months, p = 0.008) presented with improved overall survival (OS) prognosis. RPA (HR 1.66; 95% CI 1.44-1.91; p < 0.001), GPA (HR 1.65; p < 0.001), DS-GPA (HR 1.60; p < 0.001) and LabBM score (HR 1.69; p < 0.001) were statistically significantly associated with OS. In multivariate analysis, DS-GPA (HR 1.59; p < 0.001), neurological deficits (HR 1.26; p = 0.021) and LabBM score (HR 1.57; p < 0.001) presented with statistical independent association with OS. CONCLUSION: A- to oligosymptomatic BM as well as synchronous diagnosis of SCLC and BM were associated with improved OS. Established prognostic scores could be validated in this large SCLC BM real-life cohort.

Outcome evaluation in glioblastoma patients older than 65 years: Importance of individual assessment of treatment tolerance.

BACKGROUND: In this retrospective study, we evaluated the outcome of patients with primary glioblastoma multiforme (GBM), aged >= 65 years, treated in our institution from 2003 to 2009, and compared the outcome of patients admitted into the Nordic Glioma Study (NGS group) to the outcomes of elderly patients treated during the same time period outside of studies. The primary endpoint was overall survival (OS). PATIENTS AND METHODS: The study population of 70 patients (32 females) aged 65 - 83, median 71 years, was divided into three groups: the NGS group consisted of 35 patients, 1 group of 12 patients estimated as frail was treated with back then standard radiotherapy of 60 Gy (RT arm), and 23 "fit elderly" were treated with standard radio-chemotherapy (RCT arm). 31 of the 70 patients underwent gross total resection (44%), 21 patients had subtotal resection (30%), and 18 patients underwent biopsy (26%). RESULTS: Survival in the three study arms of the NGS group was very similar to the outcomes in the whole cohort of the Nordic Glioma Study (6 - 10 months). Median OS in the RCT arm was 21.0 (6 - 47) months vs. 3.0 (0.3 - 21) months in the RT arm of the NGS group. In the temozolomide (TMZ) arm, 2 of 10 patients (20%) suffered from grade 3 - 4 thrombocytopenia. In the RCT arm, grade 3 hematologic toxicity occurred in 2 of 23 patients (8.7%) and in 1 patient of the RT arm (8.3%). This retrospective single center experience shows the wide variety of outcomes in elderly patients with GBM and underlines their need for individualized, geriatric assessment-based therapy planning.

Computer-assisted and fractal-based morphometric assessment of microvascularity in histological specimens of gliomas.

Fractal analysis is widely applied to investigate the vascular system in physiological as well as pathological states. We propose and examine a computer-aided and fractal-based image analysis technique to quantify the microvascularity in histological specimens of WHO grade II and III gliomas. A computer-aided and fractal-based analysis was used to describe the microvessels and to quantify their geometrical complexity in histological specimens collected from 17 patients. The statistical analysis showed that the fractal-based indexes are the most discriminant parameters to describe the microvessels. The computer-aided quantitative analysis also showed that grade III gliomas are generally more vascularized than grade II gliomas. The fractal parameters are reliable quantitative indicators of the neoplastic microvasculature, making them potential surrogate biomarkers. The qualitative evaluation currently performed by the neuropathologist can be combined with the computer-assisted quantitative analysis of the microvascularity to improve the diagnosis and optimize the treatment of patients with brain cancer.