Analysis of deep optic nerve head structures with spectral domain and swept-source optical coherence tomography

PURPOSE

Histological evidence indicates that the earliest structural changes to the optic nerve head (ONH) in glaucoma occur in the lamina cribrosa (LC) and its interface with the sclera. However, clinical imaging of these structures remains challenging. We compared the visibility of deep ONH structures with newer iterations of spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT).

METHODS

Twelve patients with open-angle glaucoma were imaged with SD-OCT with 24 radial B-scans centred on Bruch's membrane opening (BMO) and SS-OCT with a horizontal and vertical raster scan pattern containing five lines each, centred on the ONH. Single best-matched horizontal and vertical scans from the two modalities were selected and exported. Three independent observers masked to modality determined if BMO, posterior choroid surface, anterior scleral canal opening and anterior and posterior LC insertions into the sclera were detectable in the matched B-scan images. We determined the interobserver agreement and concordance in detecting each structure with the two OCT imaging modalities.

RESULTS

There was a high interobserver agreement with both SS-OCT and SD-OCT (inter-item correlations: 0.81-0.93 and 0.77-0.82, respectively). There was a consistent tendency for higher overall detection rates with SS-OCT, however, the differences failed to reach statistical significance. With respect to individual structures, only the posterior LC insertion in the nasal quadrant was statistically different, with a detection rate of 13 and 6 (pooled out of a total of 36 across the three observers) with SS-OCT and SD-OCT, respectively (p=0.04).

CONCLUSION

Overall, both SS-OCT and SD-OCT showed statistically equivalent visualisation of ONH structures, however, SS-OCT tended to have higher visualisation rates.

Quantification of Measurable Residual Disease Detection by Next-Generation Sequencing-Based Clonality Testing in B-Cell and Plasma Cell Neoplasms

Next-generation sequencing (NGS)-based measurable residual disease (MRD) monitoring in post-treatment settings can be crucial for relapse risk stratification in patients with B-cell and plasma cell neoplasms. Prior studies have focused on validation of various technical aspects of the MRD assays, but more studies are warranted to establish the performance characteristics and enable standardization and broad utilization in routine clinical practice. Here, the authors describe an NGS-based IGH MRD quantification assay, incorporating a spike-in calibrator for monitoring B-cell and plasma cell neoplasms based on their unique IGH rearrangement status. Comparison of MRD status (positive or undetectable) by NGS and flow cytometry (FC) assays showed high concordance (91%, 471/519 cases) and overall good linear correlation in MRD quantitation, particularly for chronic lymphocytic leukemia and B-lymphoblastic leukemia/lymphoma (R = 0.85). Quantitative correlation was lower for plasma cell neoplasms, where underestimation by FC is a known limitation. No significant effects on sequencing efficiency by the spike-in calibrator were observed, with excellent inter- and intra-assay reproducibility within the authors' laboratory, and in comparison to an external laboratory, using the same assay and protocols. Assays performed both at internal and external laboratories showed highly concordant MRD detection (100%) and quantitation (R = 0.97). Overall, this NGS-based MRD assay showed highly reproducible results with quantitation that correlated well with FC MRD assessment, particularly for B-cell neoplasms.

Clonal Characterization and Somatic Hypermutation (SHM) Assessment by Next Generation Sequencing in Chronic Lymphocytic Leukemia/ Small Lymphocytic Lymphoma (CLL/SLL): A Detailed Description of the Technical Performance, Clinical Utility, and Platform Comparison

Somatic hypermutation (SHM) status of the immunoglobulin heavy variable (IGHV) gene is essential for treating chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) patients. Unlike the conventional low-throughput method, assessment of SHM by next generation sequencing (NGS) has potential for uniformity and scalability, however it lacks standardization or guidelines for routine clinical use. We critically assessed the performance of an amplicon-based NGS assay across 458 samples. Using a validation cohort (35 samples), the comparison of two platforms (Ion Torrent vs Illumina) and two primer sets (Leader vs FR1) in their ability to identify clonotypic IGHV rearrangement(s) revealed 97% concordance. The mutation rates were identical by both platforms when using the same primer set (FR1), while a slight overestimation bias (+0.326%) was found when comparing FR1 to Leader primers. However, for nearly all patients this did not affect the stratification into mutated or unmutated categories suggesting that use of FR1 may provide comparable results if Leader sequencing is not available, while also allowing for a simpler NGS laboratory workflow. In routine clinical practice (423 samples), the productive rearrangement was successfully detected by either primer set (Leader 97.7%, FR1 94.7%) and a combination of both in problematic cases reduced the failure rate to 1.2%. Higher sensitivity of the NGS-based analysis also detected a higher frequency of double IGHV rearrangements (19.1%) compared to traditional approaches.

Immune-checkpoint inhibitor therapy response evaluation using oncophysics-based mathematical models

The field of oncology has transformed with the advent of immunotherapies. The standard of care for multiple cancers now includes novel drugs that target key checkpoints that function to modulate immune responses, enabling the patient's immune system to elicit an effective anti-tumor response. While these immune-based approaches can have dramatic effects in terms of significantly reducing tumor burden and prolonging survival for patients, the therapeutic approach remains active only in a minority of patients and is often not durable. Multiple biological investigations have identified key markers that predict response to the most common form of immunotherapy-immune checkpoint inhibitors (ICI). These biomarkers help enrich patients for ICI but are not 100% predictive. Understanding the complex interactions of these biomarkers with other pathways and factors that lead to ICI resistance remains a major goal. Principles of oncophysics-the idea that cancer can be described as a multiscale physical aberration-have shown promise in recent years in terms of capturing the essence of the complexities of ICI interactions. Here, we review the biological knowledge of mechanisms of ICI action and how these are incorporated into modern oncophysics-based mathematical models. Building on the success of oncophysics-based mathematical models may help to discover new, rational methods to engineer immunotherapy for patients in the future. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Impact of FAPI-PET/CT on Target Volume Definition in Radiation Therapy of Locally Recurrent Pancreatic Cancer

Simple Summary

We demonstrate how manual target definition based on contrast-enhanced computed tomography is highly unreliable and inconsistent. In a second step, we used a novel positron emission tomography tracer, FAPI (68Ga-labeled fibroblast activation protein inhibitor) for target volume definition. FAPI-PET/CT contains biologic information as it visualizes cancer associated fibroblasts. The pioneering use of FAPI PET/CT in radiation treatment planning improved target definition in locally recurrent pancreatic cancer.

Abstract

(1) Background: A new radioactive positron emission tomography (PET) tracer uses inhibitors of fibroblast activation protein (FAPI) to visualize FAP-expressing cancer associated fibroblasts. Significant FAPI-uptake has recently been demonstrated in pancreatic cancer patients. Target volume delineation for radiation therapy still relies on often less precise conventional computed tomography (CT) imaging, especially in locally recurrent pancreatic cancer patients. The need for improvement in precise tumor detection and delineation led us to innovatively use the novel FAPI-PET/CT for radiation treatment planning. (2) Methods: Gross tumor volumes (GTVs) of seven locally recurrent pancreatic cancer cases were contoured by six radiation oncologists. In addition, FAPI-PET/CT was used to automatically delineate tumors. The interobserver variability in target definition was analyzed and FAPI-based automatic GTVs were compared to the manually defined GTVs. (3) Results: Target definition differed significantly between different radiation oncologists with mean dice similarity coefficients (DSCs) between 0.55 and 0.65. There was no significant difference between the volumes of automatic FAPI-GTVs based on the threshold of 2.0 and most of the manually contoured GTVs by radiation oncologists. (4) Conclusion: Due to its high tumor to background contrast, FAPI-PET/CT seems to be a superior imaging modality compared to the current gold standard contrast-enhanced CT in pancreatic cancer. For the first time, we demonstrate how FAPI-PET/CT could facilitate target definition and increases consistency in radiation oncology in pancreatic cancer.

Routine Evaluation of Minimal Residual Disease in Myeloma Using Next-Generation Sequencing Clonality Testing: Feasibility, Challenges, and Direct Comparison with High-Sensitivity Flow Cytometry

The 2016 International Myeloma Working Group consensus recommendations emphasize high-sensitivity methods for minimal residual disease (MRD) detection, treatment response assessment, and prognostication. Next-generation sequencing (NGS) of IGH gene rearrangements is highly specific and sensitive, but its description in routine clinical practice and performance comparison with high-sensitivity flow cytometry (hsFC) remain limited. In this large, single-institution study including 438 samples from 251 patients, the use of NGS targeting the IGH and IGK genes for clonal characterization and monitoring, with comparison to hsFC, is described. The index clone characterization success rate was 93.6% (235/251), which depended on plasma cell (PC) cellularity, reaching 98% when PC ≥10% and below 80% when PC <5%. A total of 85% of cases were successfully characterized using leader and FR1 primer sets, and most clones showed high somatic hypermutation rates (median, 8.1%). Among monitoring samples from 124 patients, 78.6% (147/187) had detectable disease by NGS. Concordance with hsFC was 92.9% (170/183). Discordant cases encompassed 8 of 124 hsFC MRD+/NGS MRD− patients (6.5%) and 4 of 124 hsFC MRD−/NGS MRD+ patients (3.2%), all with low-level disease near detection limits for both assays. Among concordant hsFC MRD−/NGS MRD− cases, only 5 of 24 patients (20.8%) showed subsequent overt relapse at 3-year follow-up. HsFC and NGS showed similar operational sensitivity, and the choice of test may depend on practical, rather than test performance, considerations.

Genotypic correlation between post discharge Clostridiodes difficle infection (CDI) and previous unit-based contacts

BACKGROUND

Cases of Clostridiodes difficile infection (CDI) diagnosed after hospital discharge account for a substantial proportion of new infections. It is unclear whether post-discharge infections originate from hospital-based transmission.

METHODS

This was a Retrospective cohort study at a tertiary-care cancer center (non-outbreak setting). For all laboratory-identified cases of CDI in 2015-2016, patients with post-discharge (PD) CDI within eight weeks of their hospital stay were included in the study. Isolates from PD-CDI cases and their CDI-positive unit-based contacts were first genotyped by multilocus sequence typing (MLST). Common strains were further examined by core genome sequencing (CGS) to evaluate transmission links.

RESULTS

Of 173 cases examined by MLST, 50% of PD cases matched previous unit contacts. Next, 34 isolates, including 16 PD cases and their 18-unit contacts were examined by CGS. None were ≤3 single-nucleotide variants apart. Seventy percent of PD cases had in-hospital antibiotic exposure before CDI onset in the community.

CONCLUSION

Our study results suggest that symptomatic CDI cases are not a substantial source of transmission to PD cases. Frequent antibiotic exposure in post-discharge CDI cases is an important target for surveillance and stewardship efforts.

18F-sodium fluoride positron emission tomography-computed tomography in acute aortic syndrome

Background

Acute aortic syndrome is characterised by diseases that disrupt the intima and weaken the aorta. This damaged aorta is prone to aneurysmal dilation and ultimately rupture – a catastrophic event. 18F-sodium fluoride positron emission tomography and computed tomography (PET-CT) is a promising multimodality imaging technique that informs on the pathological state of the aorta. In abdominal aortic aneurysms (a chronic aortic disease), 18F-sodium fluoride PET uptake is associated with aortic expansion and requirement for aortic repair.

Purpose

The aim of this study was to describe aortic 18F-sodium fluoride uptake in patients with acute aortic syndrome for the first time.

Methods

Patients with intramural haematomas, aortic dissections or penetrating aortic ulcers, along with healthy control subjects, underwent contrast-enhanced 18F-sodium fluoride PET-CT. 18F-Sodium fluoride uptake was assessed using standardised uptake values and corrected for background blood pool activity to obtain tissue-to-background ratios (TBR).

Results

Forty-six patients and twenty healthy control subjects were matched for age, gender, body mass index, ischaemic heart disease and diabetes mellitus. Participants with acute aortic syndrome had widespread aortic 18F-sodium fluoride uptake. Radiotracer binding in patients with acute aortic syndrome was substantially greater than healthy subjects (TBR 2.00±0.45 vs 1.36±0.39, p&lt;0.001). Subgroup analysis in patients with untreated type B acute aortic dissection revealed peak radiotracer binding at the site of intimal disruption compared to the proximal reference aorta (TBR [inter-quartile range] 1.61 [1.38–1.88] vs 1.18 [1.08–1.39] respectively; p&lt;0.001).

Radiotracer uptake was highest in patients with penetrating aortic ulcers, followed by aortic dissection and intramural haematomas (TBR (±SD) 2.19±0.55 vs 1.99±0.43 vs 1.71±0.27 respectively; p=0.046). No difference in radiotracer uptake was observed between patients with sub-acute and chronic disease (TBR (±SD) 1.94±0.37 vs 2.04±0.51, p=0.497). 18F-sodium fluoride uptake was similar between Stanford Type A and Type B dissections (TBR (±SD) 1.98±0.49, 2.00±0.44, p=0.851). 18F-Sodium fluoride binding was independent of maximum aortic diameter (R2 = 0.036, p=0.21).

Conclusion

Our preliminary findings suggest that aortic 18F-sodium fluoride uptake is increased in patients with acute aortic syndrome, especially around the site of intimal disruption or penetrating aortic ulcers. This technique appears to identify disease activity that may have clinical applications for assessing prognosis and guiding therapeutic interventions.

18F-NaF PET/CT in Acute Aortic Syndrome

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Whole genome, transcriptome and methylome profiling enhances actionable target discovery in high-risk pediatric cancer

The Zero Childhood Cancer Program is a precision medicine program to benefit children with poor-outcome, rare, relapsed or refractory cancer. Using tumor and germline whole genome sequencing (WGS) and RNA sequencing (RNAseq) across 252 tumors from high-risk pediatric patients with cancer, we identified 968 reportable molecular aberrations (39.9% in WGS and RNAseq, 35.1% in WGS only and 25.0% in RNAseq only). Of these patients, 93.7% had at least one germline or somatic aberration, 71.4% had therapeutic targets and 5.2% had a change in diagnosis. WGS identified pathogenic cancer-predisposing variants in 16.2% of patients. In 76 central nervous system tumors, methylome analysis confirmed diagnosis in 71.1% of patients and contributed to a change of diagnosis in two patients (2.6%). To date, 43 patients have received a recommended therapy, 38 of whom could be evaluated, with 31% showing objective evidence of clinical benefit. Comprehensive molecular profiling resolved the molecular basis of virtually all high-risk cancers, leading to clinical benefit in some patients.

Catheter ablation for atrial fibrillation in patients with reduced systolic function: a national perspective

Background

Randomized trials have shown improvement in hard clinical end points when catheter ablation (CA) was employed as a management strategy for certain atrial fibrillation (AF) patients with heart failure and reduced ejection fraction (HFrEF). We sought to determine real world data on mortality and complications after utilization of CA in such patients.

Methods and results

Data were derived from National Inpatient Sample from January 2008 to August 2015. Patients were identified using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes. Baseline characteristics and outcomes were compared among AF and HFrEF patients undergoing CA or not. Propensity matching was done to mitigate selection bias and balance confounding variables. Various CA related complications were assessed. Logistic regression was done to determine predictors of mortality in our study cohort. A total of 2,569,919 patients were enrolled and out of these approximately 7773 patients underwent CA. Mortality was significantly better in CA group in both unmatched (1.2% vs. 4.9%, p&lt;0.01) and propensity matched cohorts (1.2% vs. 3.6%, p&lt;0.01). Overall complication rate was 10.2% in CA cohort and were primarily cardiac and neurological in origin. In regression analysis, CA remains a strong predictor of reduced mortality (OR 0.301, 95% CI 0.184–0.494).

Conclusion

CA is associated with improved mortality in admitted AF patients with concomitant HFrEF. Overall complication rate after CA was modest at 10.2%.

Funding Acknowledgement

Type of funding source: None

Stereotactic Radiosurgery With Concurrent Immunotherapy in Melanoma Brain Metastases Is Feasible and Effective

Objective: Stereotactic radiosurgery (SRS) is an established treatment for brain metastases in the management of metastasized melanoma. The increasing use of checkpoint inhibitors in melanoma therapy leads to combined treatment schemes consisting of immunotherapy and SRS that need to be evaluated regarding safety and feasibility. Methods: We retrospectively analyzed 36 patients suffering from cerebral metastasized melanoma. Between November 2011 and May 2016, altogether 66 brain metastases were treated with single-fraction SRS (18-20 Gy prescribed to the 80% isodose) in combination with a checkpoint inhibitor (ipilimumab: 82%, pembrolizumab: 14% or nivolumab: 4%), administered within 3 months before or after SRS. Toxicity was evaluated with focus on the incidence of central nervous system (CNS) radiation necrosis (CRN). Overall survival (OS), freedom from local progression (FFLP), freedom from central nervous system radiation necrosis (FFCRN), and freedom from distant intracranial progression (FFDIP) were analyzed using the Kaplan-Meier method. Results: The median follow-up was 25 months (range: 2-115 months). Two patients (6%) presented with cerebral edema CTCAE °III and another two patients (6%) presented with one-sided muscle weakness CTCAE °III after SRS. One of these four symptomatic cases correlated with an observed CRN, the other three symptomatic cases were related to local tumor progression (n = 2) or related to the performance of additional whole brain radiotherapy (WBRT). No further CTCAE °III or °IV toxicity was seen. During follow-up, seven of the growing contrast-enhanced lesions were resected, revealing two cases of CRN and five cases of local tumor progression. Altogether, the observed CRN rate of the irradiated metastases was 6-17% at the time of analysis, ranging due to the radiologically challenging differentiation between CRN and local tumor progression. The observed ranges of the 1- and 2-years FFLP rates were 82-85% and 73-80%, respectively. The median FFDIP was 6.1 months, the median OS was 22.2 months. Conclusion: In the presented cohort, the combination of SRS and checkpoint inhibitors in the management of cerebral metastasized melanoma was safe and effective. Compared to historic data on SRS only, the observed CRN rate was acceptable. To gain resilient data on the incidence of CRN after combined treatment schemes, prospective trials are needed.

FAPI-74 PET/CT Using Either 18F-AlF or Cold-Kit 68Ga Labeling: Biodistribution, Radiation Dosimetry, and Tumor Delineation in Lung Cancer Patients

⁶⁸Ga-fibroblast activation protein inhibitors (FAPIs) 2, 4, and 46 have already been proposed as promising PET tracers. However, the short half-life of ⁶⁸Ga (68 min) creates problems with manufacture and delivery. ¹⁸F (half-life, 110 min) labeling would result in a more practical large-scale production, and a cold-kit formulation would improve the spontaneous availability. The NOTA chelator ligand FAPI-74 can be labeled with both ¹⁸F-AlF and ⁶⁸Ga. Here, we describe the in vivo evaluation of ¹⁸F-FAPI-74 and a proof of mechanism for ⁶⁸Ga-FAPI-74 labeled at ambient temperature. Methods: In 10 patients with lung cancer, PET scans were acquired at 10 min, 1 h, and 3 h after administration of 259 ± 26 MBq of ¹⁸F-FAPI-74. Physiologic biodistribution and tumor uptake were semiquantitatively evaluated on the basis of SUV at each time point. Absorbed doses were evaluated using OLINDA/EXM, version 1.1, and QDOSE dosimetry software with the dose calculator IDAC-Dose, version 2.1. Identical methods were used to evaluate one examination after injection of 263 MBq of ⁶⁸Ga-FAPI-74. Results: The highest contrast was achieved in primary tumors, lymph nodes, and distant metastases at 1 h after injection, with an SUV_max of more than 10. The effective dose per a 100-MBq administered activity of ¹⁸F-FAPI-74 was 1.4 ± 0.2 mSv, and for ⁶⁸Ga-FAPI-74 it was 1.6 mSv. Thus, the radiation burden of a diagnostic ¹⁸F-FAPI-74 PET scan is even lower than that of PET scans with ¹⁸F-FDG and other ¹⁸F tracers; ⁶⁸Ga-FAPI-74 is comparable to other ⁶⁸Ga ligands. FAPI PET/CT supported target volume definition for guiding radiotherapy. Conclusion: The high contrast and low radiation burden of FAPI-74 PET/CT favor multiple clinical applications. Centralized large-scale production of ¹⁸F-FAPI-74 or decentralized cold-kit labeling of ⁶⁸Ga-FAPI-74 allows flexible routine use.

Carbon ion radiotherapy in pancreatic cancer: A review of clinical data

Despite all efforts, pancreatic cancer remains a highly lethal disease. Only surgical resection offers a realistic chance of survival. But at diagnosis the majority of patients suffer from unresectable disease. Whereas guidelines clearly recommend systemic treatments in metastatic disease, data is limited to support a specific treatment option for locally advanced or borderline resectable pancreatic cancer. Therefore, there is an urgent need to improve treatment schemes addressing patients that suffer from unresectable pancreatic cancer. Chemotherapy, photon radiotherapy and combinations of both have shown improved local control rates but there is still a lack of evidence demonstrating an overall survival benefit of photon radiotherapy if no surgical resection is achieved. Impressive results of Japanese Phase I/II-trials investigating carbon ion radiotherapy in pancreatic cancer attracted global attention. Several studies have been initiated to validate and intensify this promising issue. This review gives an overview of the evidence and current use of carbon ion radiotherapy in pancreatic cancer.

The Role of 68Ga-FAPI PET/CT for Patients with Malignancies of the Lower Gastrointestinal Tract: First Clinical Experience

For oncologic management or radiotherapy planning, reliable staging tools are essential. The recent development of quinoline-based ligands targeting cancer-associated fibroblasts demonstrated promising preclinical and clinical results. The current study aimed to evaluate the role of fibroblast activation protein inhibitor (FAPI) PET/CT as a first clinical analysis for primary malignancies within the lower gastrointestinal tract (LGT). Methods: ⁶⁸Ga-FAPI PET/CT was performed on a cohort of 22 patients with LGT tumors, including 15 patients with metastatic disease, 1 patient with suspected local relapse, and 6 treatment-naïve patients. Uptake of ⁶⁸Ga-FAPI-04 and ⁶⁸Ga-FAPI-46 was quantified by SUV_max and SUV_mean After comparison with standard imaging, changes in tumor stage or localization and in oncologic or radiooncologic management were recorded. Results: The highest uptake of FAPI tracer was observed in liver metastases and anal cancer, with an SUV_max of 9.1 and 13.9, respectively. Because of low background activity in normal tissue, there was a high tumor-to-background ratio of more than 3 in most lesions. In treatment-naïve patients, TNM was changed in 50%, whereas in patients with metastases, new findings occurred in 47%. In total, FAPI imaging caused a high, medium, and low change in oncologic or radiooncologic management in 19%, 33%, and 29%, respectively. For almost every patient undergoing irradiation, target volume delineation was improved by ⁶⁸Ga-FAPI PET/CT. Conclusion: The present study demonstrated that both primary and metastatic LGT tumors were reliably detected by ⁶⁸Ga-FAPI PET/CT, leading to relevant changes in TNM status and oncologic or radiooncologic management. ⁶⁸Ga-FAPI PET/CT seems to be a highly promising imaging agent for the diagnosis and management of LGT tumors, potentially opening new applications for tumor staging or restaging.

Breakup of finite-size liquid filaments: Transition from no-breakup to breakup including substrate effects⋆

This work studies the breakup of finite-size liquid filaments, when also including substrate effects, using direct numerical simulations. The study focuses on the effects of three parameters: Ohnesorge number, the ratio of the viscous forces to inertial and surface tension forces, the liquid filament aspect ratio, and where there is a substrate, a measure of the fluid slip on the substrate, i.e. slip length. Through these parameters, it is determined whether a liquid filament breaks up during the evolution toward its final equilibrium state. Three scenarios are identified: a collapse into a single droplet, the breakup into one or multiple droplets, and recoalescence into a single droplet after the breakup (or even possibly another breakup after recoalescence). The results are compared with the ones available in the literature for free-standing liquid filaments. The findings show that the presence of the substrate promotes the breakup of the filament. The effect of the degree of slip on the breakup is also discussed. The parameter domain regions are comprehensively explored when including the slip effects. An experimental case is also carried out to illustrate the collapse and breakup of a finite-size silicon oil filament supported on a substrate, showcasing a critical length of the breakup in a physical configuration. Finally, direct numerical simulations reveal striking new details into the breakup pattern for low Ohnesorge numbers, where the dynamics are fast and the experimental imaging is not available; our results therefore significantly extend the range of Ohnesorge number over which filament breakup has been considered.

Establishment of Immunoglobulin Heavy (IGH) Chain Clonality Testing by Next-Generation Sequencing for Routine Characterization of B-Cell and Plasma Cell Neoplasms

Immunoglobulin heavy chain (IGH) clonality testing by next-generation sequencing (NGS) offers unique advantages over current low-throughput methods in the assessment of B-cell lineage neoplasms. Clinical use remains limited because assays are not standardized and validation/implementation guidelines are not yet developed. Herein, we describe our clinical validation and implementation of NGS IGH clonality testing and summarize our experience based on extensive routine use. NGS-based clonality testing targeting IGH FR1, FR2, FR3, and the conserved leader sequence upstream of FR1 was validated using commercially available kits. Data were analyzed by commercial and in-house-developed bioinformatics pipelines. Performance characteristics were evaluated directly comparing with capillary electrophoresis (CE) assays (BIOMED-2 primers). Assays were monitored after implementation (>1.5 years), concurrently testing by CE methods. A total of 1189 clinical samples were studied (94 validation, 1095 postimplementation). NGS showed superior performance compared with CE assays. For initial assessment, clonality detection rate was >97% for all malignancy types. Concordance with CE was 96%; discordances were related to higher sensitivity/resolution of NGS and improved detection in cases with high somatic hypermutation. Routine NGS clonality assessment is feasible and superior to existing assays, enabling accurate and specific index clone assessment and future tracking of all rearrangements in a patient sample. Successful implementation requires new standardization, validation, and implementation processes, which should be performed as a multicenter and multidisciplinary collaboration.

Advanced Radiation Techniques in the Treatment of Esthesioneuroblastoma: A 7-Year Single-Institution's Clinical Experience

(1) Background: Esthesioneuroblastoma (ENB) is a rare tumor entity originating from the olfactory neuroepithelium. There is a scarcity of data about different treatment strategies. Intensity modulated radiotherapy (IMRT) and carbon ion radiotherapy (CIRT) are advanced radiation techniques that might improve local tumor control. (2) Methods: This retrospective analysis contained 17 patients with ENB (Kadish stage ≥ C: 88%; n = 15). Four patients had already undergone previous radiotherapy (RT). The treatment consisted of either IMRT (n = 5), CIRT (n = 4) or a combination of both techniques (n = 8). Median follow-up was 29 months. (3) Results: In patients that had not been irradiated before (n = 13), calculated overall survival (OS) and progression free survival (PFS) rates after 48 months were 100% and 81% respectively (Kaplan-Meier estimates). Two of four patients that underwent reirradiation died after RT, presumably due to tumor progression. Besides common toxicities, five patients (30%) showed mostly asymptomatic radiation-induced brain changes, most likely due to a disturbance of the blood-brain barrier. (4) Conclusions: Our results demonstrate that IMRT, CIRT, a combined approach of IMRT and CIRT as well as reirradiation with CIRT seem to be feasible and effective treatment methods in ENB.

Survival and recurrence patterns of multifocal glioblastoma after radiation therapy

Purpose

It is hypothesized that multifocal glioblastoma (mGBM) is associated with worse prognosis compared to unifocal disease (uGBM). This study aims to investigate the differences in survival rates and progression patterns of patients between these two groups after radiation therapy.

Patients and methods

We retrospectively analyzed 265 patients with primary GBM undergoing radiation therapy at the Department of Radiation Oncology, University Hospital Heidelberg, Germany, between 2004 and 2013. Of these, 202 (76%) were uGBMs and 63 (24%) were mGBMs. First, progression-free survival (PFS) and overall survival (OS) between groups were compared using the Kaplan-Meier method. Second, univariate and multivariate Cox proportional hazards regression was applied to discern prognostic and predictive factors with PFS and OS in the cohorts. Third, recurrence patterns of uGBMs and mGBMs were assessed on follow-up MRIs and compared using the chi-squared test.

Results

As compared to patients with uGBM, patients with mGBM experienced significantly worse median OS (11.5 vs 14.8 months, P=0.032). Overall, 195 (73.0%) patients experienced tumor progression: 153 (75.7%) patients with uGBM and 46 (73.0%) patients with mGBM. There were no significant differences in PFS between the respective groups (6.5 vs 6.6 months, P=0.750). Of note, concomitant temozolomide treatment was associated with an OS benefit in both uGBM and mGBM by about five months (P=0.006 and P<0.001). Furthermore, there were no significant differences in progression patterns of uGBM and mGBM. Both recurred as unifocal and multifocal disease (P=0.51), and local vs distant brain recurrences occurred similarly in both groups (OR=1.33, P=0.53).

Conclusion

Multifocality is an independent predictor of survival in GBM. Concomitant temozolomide treatment improved OS of patients with mGBM and uGBM. Both disease types showed similar patterns of progression. Current target volume concepts seem to be adequate in both unifocal and multifocal GBMs. GBM, the most common primary brain tumor in adults, is associated with poor survival. We show herein that multifocality is an independent prognostic factor for survival. We also illustrate that the progression patterns of both unifocal and multifocal GBM are similar.

Abstract P4-10-09: Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience

Background:

Stage I-III TNBC patients have a high risk of disease relapse during the first 5 years after diagnosis. However, there is limited data on the risk of late relapse in TNBC survivors who are disease free at 5 years or more from diagnosis. We sought to characterize this risk in a cohort of TNBC long-term survivors from a large institutional database.

Methods:

The MD Anderson Breast Cancer Management System database was queried for TNBC survivors who were disease free 5 years or more from diagnosis. Demographic, tumor, and treatment data was extracted. Electronic medical records were searched to confirm pathology reports for invasive breast cancer diagnosis, triple negative receptor status, and hormone receptor percentage (%). The primary and secondary outcomes of interest were relapse free survival (RFS) and distant relapse free survival (DRFS). Patients were censored at time of developing a second primary breast cancer or at last follow-up time for those who were alive during the study. We used ACP-ASCO definition of ER and PR &lt;1% and HER2/neu negative (IHC 0-1 or ratio &lt;2 and average copy number &lt;4) but also included patients with low ER/PR(1-9%) and HER2 normal. Kaplan-Meier analysis was performed to compare RFS and DRFS for the overall population and categorized by ER/PR &lt;1%, and ER/PR 1-9%.

Results:

We identified 1038 patients who had a median follow-up of 8.0 years. Receptor % information was available on 69% of patients, with 78% of them meeting current TNBC definition. From the total cohort of 130, 12.5% suffered event(s) that occurred after 5 years from diagnosis, with 86.2% of them occurring within 5-10 years of diagnosis. The event rate was 16.4% among patients with ER/PR 1-9% versus 11.3% among patients with ER/PR &lt;1%. Table 1 shows RFS and DRFS by year from diagnosis for the entire cohort and categorized by % receptor. 18 patients developed second primary breast cancer as first event and were censored. Of total events recorded, 53(40.8%) were deaths and 77(59.2%) were recurrences, of which 51(66%) were distant and 26(34%) local, of whom 12(46.2%) subsequently developed distant metastases. Among patients who initially presented with distant recurrence, frequencies of initial sites of metastases are shown in Table 2.

Conclusions:

TNBC long term survivors are still at risk for relapse events after 5 years from diagnosis, and it is important to quantity this risk when counseling our patients. Frequency of late events was higher among patients with low hormone receptor positivity. Multivariate modeling of predictors of late recurrence is ongoing.

Table 1: RFS and DRFS by Year from Diagnosis All PatientsER/PR &lt;1%ER/PR 1-9%Year From DiagnosisRFSDRFSRFSDRFSRFSDRFS4-51.01.01.01.01.01.05-60.950.960.940.950.940.956-70.930.940.930.940.910.927-80.900.920.900.920.870.898-90.860.880.870.890.810.849-100.840.870.840.860.800.8310-120.810.840.810.830.800.8312-150.730.780.730.750.670.74

Table 2: Site of Initial Distant RecurrenceSiteN (%)Lung/Pleura28 (54.9)Bone19 (37.3)Distant Lymph Nodes19 (37.3)Liver11 (21.6)Brain/Spinal Cord8 (15.7)Colorectal/Pancreas/Kidney/Adrenal6 (11.7)Other2 (3.9)*Patients presenting with multiple sites of distant recurrence are counted in each category.

Citation Format: Reddy SM, Sinha A, Syed M, Barcenas C, Valero V. Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-10-09.

Brain tumour cells interconnect to a functional and resistant network

Astrocytic brain tumours, including glioblastomas, are incurable neoplasms characterized by diffusely infiltrative growth. Here we show that many tumour cells in astrocytomas extend ultra-long membrane protrusions, and use these distinct tumour microtubes as routes for brain invasion, proliferation, and to interconnect over long distances. The resulting network allows multicellular communication through microtube-associated gap junctions. When damage to the network occurred, tumour microtubes were used for repair. Moreover, the microtube-connected astrocytoma cells, but not those remaining unconnected throughout tumour progression, were protected from cell death inflicted by radiotherapy. The neuronal growth-associated protein 43 was important for microtube formation and function, and drove microtube-dependent tumour cell invasion, proliferation, interconnection, and radioresistance. Oligodendroglial brain tumours were deficient in this mechanism. In summary, astrocytomas can develop functional multicellular network structures. Disconnection of astrocytoma cells by targeting their tumour microtubes emerges as a new principle to reduce the treatment resistance of this disease.

The BioPAX community standard for pathway data sharing

BioPAX (Biological Pathway Exchange) is a standard language to represent biological pathways at the molecular and cellular level. Its major use is to facilitate the exchange of pathway data (http://www.biopax.org). Pathway data captures our understanding of biological processes, but its rapid growth necessitates development of databases and computational tools to aid interpretation. However, the current fragmentation of pathway information across many databases with incompatible formats presents barriers to its effective use. BioPAX solves this problem by making pathway data substantially easier to collect, index, interpret and share. BioPAX can represent metabolic and signaling pathways, molecular and genetic interactions and gene regulation networks. BioPAX was created through a community process. Through BioPAX, millions of interactions organized into thousands of pathways across many organisms, from a growing number of sources, are available. Thus, large amounts of pathway data are available in a computable form to support visualization, analysis and biological discovery.