18F-FDG-Based Radiomics and Machine Learning: Useful Help for Aortic Prosthetic Valve Infective Endocarditis Diagnosis?

BACKGROUND

Fluorine-18 fluorodeoxyglucose (¹⁸F-FDG)-positron emission tomography (PET)/computed tomography (CT) results in better sensitivity for prosthetic valve endocarditis (PVE) diagnosis, but visual image analysis results in relatively weak specificity and significant interobserver variability.

OBJECTIVES

The primary objective of this study was to evaluate the performance of a radiomics and machine learning-based analysis of ¹⁸F-FDG PET/CT (PET-ML) as a major criterion for the European Society of Cardiology score using machine learning as a major imaging criterion (ESC-ML) in PVE diagnosis. The secondary objective was to assess performance of PET-ML as a standalone examination.

METHODS

All ¹⁸F-FDG-PET/CT scans performed for suspected aortic PVE at a single center from 2015 to 2021 were retrospectively included. The gold standard was expert consensus after at least 3 months' follow-up. The machine learning (ML) method consisted of manually segmenting each prosthetic valve, extracting 31 radiomics features from the segmented region, and training a ridge logistic regressor to predict PVE. Training and hyperparameter tuning were done with a cross-validation approach, followed by an evaluation on an independent test database.

RESULTS

A total of 108 patients were included, regardless of myocardial uptake, and were divided into training (n = 68) and test (n = 40) cohorts. Considering the latter, PET-ML findings were positive for 13 of 22 definite PVE cases and 3 of 18 rejected PVE cases (59% sensitivity, 83% specificity), thus leading to an ESC-ML sensitivity of 72% and a specificity of 83%.

CONCLUSIONS

The use of ML for analyzing ¹⁸F-FDG-PET/CT images in PVE diagnosis was feasible and beneficial, particularly when ML was included in the ESC 2015 criteria. Despite some limitations and the need for future developments, this approach seems promising to optimize the role of ¹⁸F-FDG PET/CT in PVE diagnosis.

Plasma lysosphingolipids in GRN-related diseases: Monitoring lysosomal dysfunction to track disease progression

GRN mutations are among the main genetic causes of frontotemporal dementia (FTD). Considering the progranulin involvement in lysosomal homeostasis, we aimed to evaluate if plasma lysosphingolipids (lysoSPL) are increased in GRN mutation carriers, and whether they might represent relevant fluid-based biomarkers in GRN-related diseases. We analyzed four lysoSPL levels in plasmas of 131 GRN carriers and 142 non-carriers, including healthy controls and patients with frontotemporal dementias (FTD) carrying a C9orf72 expansion or without any mutation. GRN carriers consisted of 102 heterozygous FTD patients (FTD-GRN), three homozygous patients with neuronal ceroid lipofuscinosis-11 (CLN-11) and 26 presymptomatic carriers (PS-GRN), the latter with longitudinal assessments. Glucosylsphingosin d18:1 (LGL1), lysosphingomyelins d18:1 and isoform 509 (LSM18:1, LSM509) and lysoglobotriaosylceramide (LGB3) were measured by electrospray ionization-tandem mass spectrometry coupled to ultraperformance liquid chromatography. Levels of LGL1, LSM18:1 and LSM509 were increased in GRN carriers compared to non-carriers (p < 0.0001). No lysoSPL increases were detected in FTD patients without GRN mutations. LGL1 and LSM18:1 progressively increased with age at sampling, and LGL1 with disease duration, in FTD-GRN. Among PS-GRN carriers, LSM18:1 and LGL1 significantly increased over 3.4-year follow-up. LGL1 levels were associated with increasing neurofilaments in presymptomatic carriers. This study evidences an age-dependent increase of β-glucocerebrosidase and acid sphingomyelinase substrates in GRN patients, with progressive changes as early as the presymptomatic phase. Among FTD patients, plasma lysoSPL appear to be uniquely elevated in GRN carriers, and thus might serve as suitable non-invasive disease-tracking biomarkers of progression, specific to the pathophysiological process. Finally, this study might add lysoSPL to the portfolio of fluid-based biomarkers, and pave the way to disease-modifying approaches based on lysosomal function rescue in GRN diseases.

Brain Metabolic Profile in Presymptomatic GRN Carriers Throughout a 5-Year Follow-up

BACKGROUND AND OBJECTIVES

GRN variants are a frequent cause of familial frontotemporal dementia (FTD). Monitoring disease progression in asymptomatic carriers of genetic variants is a major challenge in delivering preventative therapies before clinical onset. This study aimed to assess the usefulness of fluorodeoxyglucose (FDG)-PET in identifying metabolic changes in presymptomatic GRN carriers (PS-GRN+) and to trace their longitudinal progression.

METHODS

Participants were longitudinally evaluated over 5 years in a prospective cohort study focused on GRN disease (Predict-PGRN). They underwent cognitive/behavioral assessment, plasma neurofilament measurement, brain MRI, and FDG-PET. Voxel-wise comparisons of structural and metabolic imaging data between 2 groups were performed for each time point. Longitudinal PET changes were evaluated with voxel-wise comparisons and the metabolic percent annual changes method. The association of regional brain metabolism with plasma neurofilament and cognitive changes was analyzed.

RESULTS

Among the 80 individuals enrolled in the study, 58 (27 PS-GRN+ and 31 noncarriers) were included in the analyses. Cross-sectional comparisons between PS-GRN+ and controls found a significant hypometabolism in the left superior temporal sulcus (STS) region (encompassing the middle and superior temporal gyri), approximately 15 years before the expected disease onset, without significant cortical atrophy. The longitudinal metabolic decline over the following 5 years peaked around the right STS in carriers (p < 0.001), without significantly greater volume loss compared with that in controls. Their estimated annualized metabolic decrease (-1.37%) was higher than that in controls (-0.21%, p = 0.004). Lower glucose uptake was associated with higher neurofilament increase (p = 0.003) and lower frontal cognitive scores (p = 0.014) in PS-GRN+.

DISCUSSION

This study detected brain metabolic changes in the STS region, preceding structural and cognitive alterations, thus contributing to the characterization of the pathochronology of preclinical GRN disease. Owing to the STS involvement in the perception of facially communicated cues, it is likely that its dysfunction contributes to social cognition deficits characterizing FTD. Overall, our study highlights brain metabolic changes as an early disease-tracking biomarker and proposes annualized percent decrease as a metric to monitor therapeutic response in forthcoming trials.

Idiopathic normal pressure hydrocephalus and frontotemporal dementia: an unexpected association

Idiopathic normal pressure hydrocephalus has a complex multifactorial pathogenesis and is associated with Alzheimer's disease in many patients. To date, it is not well known if a similar association exists with behavioural variant of frontotemporal lobar degeneration. In a first step, we compare the prevalence of idiopathic normal pressure hydrocephalus in two groups of patients, one with behavioural variant of frontotemporal lobar degeneration (n = 69) and the other with Alzheimer's disease (n = 178). In the second step, we describe more precisely the phenotype of patients with the association of idiopathic normal pressure hydrocephalus and behavioural variant of frontotemporal lobar degeneration. Firstly, we report that the prevalence of idiopathic normal pressure hydrocephalus was far higher in the group of patients with behavioural variant of frontotemporal lobar degeneration than in the group of patients with Alzheimer's disease (7.25% and 1.1%, respectively, P = 0.02). Secondly, we show that patients with the double diagnosis share common clinical and para-clinical features of both idiopathic normal pressure hydrocephalus and behavioural variant of frontotemporal lobar degeneration patients, including CSF shunting efficacy in real-life experience. Overall, our results suggest a link between these two conditions and should encourage neurologists to look for idiopathic normal pressure hydrocephalus in their behavioural variant of frontotemporal lobar degeneration patients in the event of gait disturbances; the benefit/risk balance could indeed be in favour of shunt surgery for selected patients with this newly described entity.

Functional Alterations Due to COVID-19 Lung Lesions-Lessons From a Multicenter V/Q Scan-Based Registry

PURPOSE

In coronavirus disease 2019 (COVID-19) patients, clinical manifestations as well as chest CT lesions are variable. Lung scintigraphy allows to assess and compare the regional distribution of ventilation and perfusion throughout the lungs. Our main objective was to describe ventilation and perfusion injury by type of chest CT lesions of COVID-19 infection using V/Q SPECT/CT imaging.

PATIENTS AND METHODS

We explored a national registry including V/Q SPECT/CT performed during a proven acute SARS-CoV-2 infection. Chest CT findings of COVID-19 disease were classified in 3 elementary lesions: ground-glass opacities, crazy-paving (CP), and consolidation. For each type of chest CT lesions, a semiquantitative evaluation of ventilation and perfusion was visually performed using a 5-point scale score (0 = normal to 4 = absent function).

RESULTS

V/Q SPECT/CT was performed in 145 patients recruited in 9 nuclear medicine departments. Parenchymal lesions were visible in 126 patients (86.9%). Ground-glass opacities were visible in 33 patients (22.8%) and were responsible for minimal perfusion impairment (perfusion score [mean ± SD], 0.9 ± 0.6) and moderate ventilation impairment (ventilation score, 1.7 ± 1); CP was visible in 43 patients (29.7%) and caused moderate perfusion impairment (2.1 ± 1.1) and moderate-to-severe ventilation impairment (2.5 ± 1.1); consolidation was visible in 89 patients (61.4%) and was associated with moderate perfusion impairment (2.1 ± 1) and severe ventilation impairment (3.0 ± 0.9).

CONCLUSIONS

In COVID-19 patients assessed with V/Q SPECT/CT, a large proportion demonstrated parenchymal lung lesions on CT, responsible for ventilation and perfusion injury. COVID-19-related pulmonary lesions were, in order of frequency and functional impairment, consolidations, CP, and ground-glass opacity, with typically a reverse mismatched or matched pattern.

Hypermetabolism of the spleen or bone marrow is an additional albeit indirect sign of infective endocarditis at FDG-PET

PURPOSE

This study aimed at determining the diagnostic implications of indirect signs of infection at FDG-PET-i.e., hypermetabolisms of the spleen and/or bone marrow (HSBM)-when documented in patients with known or suspected infective endocarditis (IE).

METHODS

HSBM were defined by higher mean standardized uptake values comparatively to that of the liver on FDG-PET images from patients with a high likelihood of IE and prospectively included in a multicenter study.

RESULTS

Among the 129 included patients, IE was ultimately deemed as definite in 88 cases. HSBM was a predictor of definite IE (P = 0.014; odds ratio (OR) 3.2), independently of the criterion of an abnormal cardiac FDG uptake (P = 0.0007; OR 9.68), and a definite IE was documented in 97% (29/30) of patients showing both HSBM and abnormal cardiac uptake, 78% (7/9) of patients with only abnormal cardiac uptake, 67% (42/63) of patients with only HSBM, and 37% (10/27) of patients with neither one.

CONCLUSION

In this cohort with a high likelihood of IE, HSBM is an additional albeit indirect sign of IE, independently of the criterion of an abnormal cardiac uptake, and could reinforce the suspicion of IE in the absence of any other infectious, inflammatory, or malignant disease.

Lung scintigraphy for pulmonary embolism diagnosis in COVID-19 patients: a multicenter study

In patients with novel coronavirus disease 2019 (COVID-19) referred for lung scintigraphy for suspected pulmonary embolism (PE), there has been an ongoing debate within the nuclear medicine community as to whether and when the ventilation study should be performed. Indeed, while PE diagnosis typically relies on the recognition of ventilation/perfusion (V/P) mismatched defects, the ventilation procedure potentially increases the risk of contamination to the healthcare workers. The primary aim of this study was to assess the role of ventilation imaging when performing lung scintigraphy for suspected PE in COVID-19 patients. The secondary aim was to describe practices and imaging findings in this specific population. Methods: A national registry was created in collaboration with the French Society of Nuclear Medicine to collect lung scans performed in COVID-19 patients for suspected PE. Practices of departments were assessed regarding imaging protocols and aerosol precautions. A retrospective review of V/P SPECT/CT scans was then conducted. Two physicians blinded to clinical information reviewed each case by sequentially using P SPECT, P SPECT/CT and V/P SPECT/CT images. Scans were classified in one of the four following categories: patients for whom PE could reasonably be excluded based on 1) perfusion SPECT only, 2) P SPECT/CT, 3) V/P SPECT/CT; or 4) patients with mismatched defects suggestive of PE according to the EANM criteria. Results: Data from 12 French nuclear medicine departments were collected. Lung scans were performed between 03/2020 and 04/2021. Personal protective equipment and dedicated cleaning procedures were used in all departments. Out of the 145 V/Q SPECT/CT included in the central review, PE could be excluded using only P SPECT, P SPECT/CT and V/P SPECT/CT in 27 (19%), 55 (38%) and 45 (31%) patients, respectively. V/P SPECT/CT was positive for PE in 18 (12%) patients, including 12 (67%) with a low burden of PE (≤10%). Conclusion: In this population of COVID-19 patients assessed with lung scintigraphy, PE could be confidently excluded without ventilation in only 57% of patients. Ventilation imaging was required to confidently rule out PE in 31% of patients. Overall, the prevalence of PE was low (12%).

LeSCoD: a new clinical scale for the detection of Lewy body disease in neurocognitive disorders

BACKGROUND

Dementia with Lewy bodies remains underdiagnosed in clinical practice mainly because of the low sensitivity of existing diagnostic criteria and a strong overlap with Alzheimer's pathology that can mask the Lewy phenotype.

OBJECTIVE

The objective of this study was therefore to develop and validate a new clinical scale designed to detect signs of Lewy body disease, called LeSCoD for Lewy body Screening scale in Cognitive Disorders.

METHODS

128 patients who fulfilled the clinical criteria of dementia with Lewy bodies (DLB; n = 32), Alzheimer's disease (AD; n = 77) or both (n = 19) was prospectively enrolled. ¹⁸F-DOPA PET imaging and/or CSF biomarkers were available in some patients. LeSCoD scale was systematically administered and the potential correlation with ¹⁸F-DOPA PET imaging was evaluated in a subgroup of patients.

RESULTS

LeSCoD scale showed robust internal and external validity. We determined a cut-off of 10 above which the sensitivity and specificity for Lewy body disease diagnosis were 86% and 95%, respectively. The LeSCoD scale correlated with striatal dopamine uptake in ¹⁸F-DOPA PET.

CONCLUSION

LeSCoD scale is a simple and reliable tool for the evaluation of Lewy body disease in routine clinical practice, with a higher sensitivity and specificity than the existing criteria. It might be an alternative to the use of dopamine-specific imaging.

Improving the Diagnosis of the Frontal Variant of Alzheimer's Disease with the DAPHNE Scale

Background:

The frontal variant of Alzheimer’s disease (fAD) is poorly understood and poorly defined. The diagnosis remains challenging. The main differential diagnosis is the behavioral variant of frontotemporal degeneration (bvFTD). For fAD, there is some dissociation between the clinical frontal presentation and imaging and neuropathological studies, which do not always find a specific involvement of the frontal lobes. DAPHNE is a behavioral scale, which demonstrated excellent performance to distinguish between bvFTD and AD.

Objective:

The aim of the present study was to assess the reliability of this new tool to improve the clinical diagnosis of fAD.

Methods:

Twenty fAD patients and their caregivers were prospectively included and were compared with 36 bvFTD and 22 AD patients.

Results:

The three main behavioral disorders in the fAD patients were apathy, loss of empathy, and disinhibition. Three disorders were discriminant because they were less frequent and less severe in the fAD patients than in the bvFTD patients, namely hyperorality, neglect, and perseverations. This specific pattern of behavioral disorders was corroborated by SPECT or ¹⁸FDG PET-CT scan that showed that patients with fAD could have a medial frontal hypoperfusion, whereas in bvFTD patients the orbitofrontal cortex was the main involved region, with more diffuse hypoperfusion.

Conclusion:

We demonstrated that DAPHNE had good sensitivity and good specificity to discriminate between the three groups and in particular between fAD and bvFTD patients. DAPHNE is a quick tool that could help clinicians in memory clinics not only to differentiate bvFTD from typical AD but also from fAD.

Incidental findings suggestive of COVID-19 in asymptomatic cancer patients undergoing 18F-FDG PET/CT in a low prevalence region

Purpose

To assess the rate and pattern of incidental interstitial lung abnormalities suggestive of COVID-19 on 18F-FDG PET/CT in asymptomatic cancer patients during the period of active COVID-19 circulation between March and April 2020 in a geographic area of low prevalence of the virus.

Methods

1396 18F-FDG PET/CT performed between January 1, 2020, and February 21, 2020, and between March 16, 2020, and April 17, 2020 for routine oncological indication were retrospectively analyzed. No patients had symptoms suggestive of COVID-19 at the time of the 18F-FDG PET/CT. Incidental interstitial pneumonias suggestive of COVID-19 were identified, and the 18F-FDG PET/CT patterns were described. We compared the incidence of these lesions in the pre-COVID and pandemic phases.

Results

We observed a 1.6% increase in interstitial lung abnormalities during the period of COVID-19 circulation. All had < 50% lung involvement. We describe a case series with typical and atypical interstitial pneumonias suggestive of COVID-19 as unilateral or bilateral with ground-glass opacity, consolidation, or crazy-paving patterns.

Conclusion

The relatively low increase in incidental findings suggestive of COVID-19 infection on 18F-FDG PET/CT in asymptomatic cancer patients was in accordance with the low COVID-19 transmission in our geographic region. Nevertheless, nuclear medicine physicians should familiarize themselves with typical and atypical 18F-FDG PET/CT patterns suggestive of COVID-19 pneumonia and initiate appropriate intervention where necessary.

Pretreatment 18F-FDG PET/CT Radiomics Predict Local Recurrence in Patients Treated with Stereotactic Body Radiotherapy for Early-Stage Non-Small Cell Lung Cancer: A Multicentric Study

The aim of this retrospective multicentric study was to develop and evaluate a prognostic ¹⁸F-FDG PET/CT radiomic signature in early-stage non-small cell lung cancer patients treated with stereotactic body radiotherapy (SBRT). Methods: Patients from 3 different centers (n = 27, 29, and 8) were pooled to constitute the training set, whereas the patients from a fourth center (n = 23) were used as the testing set. The primary endpoint was local control. The primary tumor was semiautomatically delineated in the PET images using the fuzzy locally adaptive Bayesian algorithm, and manually in the low-dose CT images. In total, 184 Image Biomarkers Standardization Initiative-compliant radiomic features were extracted. Seven clinical and treatment parameters were included. We used ComBat to harmonize radiomic features extracted from the 4 institutions relying on different PET/CT scanners. In the training set, variables found significant in the univariate analysis were fed into a multivariate regression model, and models were built by combining independent prognostic factors. Results: Median follow-up was 21.1 mo (range, 1.7-63.4 mo) and 25.5 mo (range, 7.7-57.8 mo) in training and testing sets, respectively. In univariate analysis, none of the clinical variables, 2 PET features, and 2 CT features were significantly predictive of local control. The best predictive models in the training set were obtained by combining one feature from PET (Information Correlation 2) and one feature from CT (flatness), reaching a sensitivity of 100% and a specificity of 96%. Another model combining 2 PET features (Information Correlation 2 and strength) reached sensitivity of 100% and specificity of 88%, both with an undefined hazard ratio (P < 0.001). The latter model obtained an accuracy of 0.91 (sensitivity, 100%; specificity, 81%), with a hazard ratio undefined (P = 0.023) in the testing set; however, other models relying on CT radiomic features only or the combination of PET and CT features failed to validate in the testing set. Conclusion: We showed that 2 radiomic features derived from ¹⁸F-FDG PET were independently associated with local control in patients with non-small cell lung cancer undergoing SBRT and could be combined in an accurate predictive model. This model could provide local relapse-related information and could be helpful in clinical decision making.

Potential for Nuclear Medicine Therapy for Glioblastoma Treatment

Glioblastoma is the most common malignant adult brain tumor and has a very poor patient prognosis. The mean survival for highly proliferative glioblastoma is only 10 to 14 months despite an aggressive current therapeutic approach known as Stupp's protocol, which consists of debulking surgery followed by radiotherapy and chemotherapy. Despite several clinical trials using anti-angiogenic targeted therapies, glioblastoma medical care remains without major progress in the last decade. Recent progress in nuclear medicine, has been mainly driven by advances in biotechnologies such as radioimmunotherapy, radiopeptide therapy, and radionanoparticles, and these bring a new promising arsenal for glioblastoma therapy. For therapeutic purposes, nuclear medicine practitioners classically use β^- particle emitters like ¹³¹I, ⁹⁰Y, ^186/188Re, or ¹⁷⁷Lu. In the glioblastoma field, these radioisotopes are coupled with nanoparticles, monoclonal antibodies, or peptides. These radiopharmaceutical compounds have resulted in a stabilization and/or improvement of the neurological status with only transient side effects. In nuclear medicine, the glioblastoma-localized and targeted internal radiotherapy proof-of-concept stage has been successfully demonstrated using β^- emitting isotopes. Similarly, α particle emitters like ²¹³Bi, ²¹¹At, or ²²⁵Ac appear to be an innovative and interesting alternative. Indeed, α particles deliver a high proportion of their energy inside or at close proximity to the targeted cells (within a few micrometers from the emission point versus several millimeters for β^- particles). This physical property is based on particle-matter interaction differences and results in α particles being highly efficient in killing tumor cells with minimal irradiation of healthy tissues and permits targeting of isolated tumor cells. The first clinical trials confirmed this idea and showed good therapeutic efficacy and less side effects, thus opening a new and promising era for glioblastoma medical care using α therapy. The objective of this literature review is focused on the developing field of nuclear medicine and aims to describe the various parameters such as targets, vectors, isotopes, or injection route (systemic and local) in relation to the clinical and preclinical results in glioblastoma pathology.

Down syndrome with posterior cortical atrophy

Down syndrome (DS) is caused by trisomy of chromosome 21. The average age of onset of Alzheimer's disease (AD) ranged from 50 to 55 years in DS, with early symptoms usually characterised by changes in behaviour and executive dysfunction. On the other hand, posterior cortical atrophy (PCA) is a rare neurodegenerative syndrome characterised by progressive impairment of visual functions in the absence of visual deficits and a pattern of atrophy involving posterior cortex. This syndrome is mostly caused by AD pathology. We report the case of patient with DS who developed PCA. While atypical variants of AD are commonly associated with an early age at onset, all focal forms of AD may potentially appear in DS. Specifying the phenotype has an impact on the care of DS patients and could help us to know the evolution. It could also provide a better understanding of the underlying mechanisms of focal forms.

Phase II Study of a Radiotherapy Total Dose Increase in Hypoxic Lesions Identified by 18F-Misonidazole PET/CT in Patients with Non-Small Cell Lung Carcinoma (RTEP5 Study)

See an invited perspective on this article on page 1043.This multicenter phase II study investigated a selective radiotherapy dose increase to tumor areas with significant ¹⁸F-misonidazole (¹⁸F-FMISO) uptake in patients with non-small cell lung carcinoma (NSCLC). Methods: Eligible patients had locally advanced NSCLC and no contraindication to concomitant chemoradiotherapy. The ¹⁸F-FMISO uptake on PET/CT was assessed by trained experts. If there was no uptake, 66 Gy were delivered. In ¹⁸F-FMISO-positive patients, the contours of the hypoxic area were transferred to the radiation oncologist. It was necessary for the radiotherapy dose to be as high as possible while fulfilling dose-limiting constraints for the spinal cord and lungs. The primary endpoint was tumor response (complete response plus partial response) at 3 mo. The secondary endpoints were toxicity, disease-free survival (DFS), and overall survival at 1 y. The target sample size was set to demonstrate a response rate of 40% or more (bilateral α = 0.05, power 1-β = 0.95). Results: Seventy-nine patients were preincluded, 54 were included, and 34 were ¹⁸F-FMISO-positive, 24 of whom received escalated doses of up to 86 Gy. The response rate at 3 mo was 31 of 54 (57%; 95% confidence interval [CI], 43%-71%) using RECIST 1.1 (17/34 responders in the ¹⁸F-FMISO-positive group). DFS and overall survival at 1 y were 0.86 (95% CI, 0.77-0.96) and 0.63 (95% CI, 0.49-0.74), respectively. DFS was longer in the ¹⁸F-FMISO-negative patients (P = 0.004). The radiotherapy dose was not associated with DFS when adjusting for the ¹⁸F-FMISO status. One toxic death (66 Gy) and 1 case of grade 4 pneumonitis (>66 Gy) were reported. Conclusion: Our approach results in a response rate of 40% or more, with acceptable toxicity. ¹⁸F-FMISO uptake in NSCLC patients is strongly associated with poor prognosis features that could not be reversed by radiotherapy doses up to 86 Gy.

Consolidation anti-CD22 fractionated radioimmunotherapy with 90Y-epratuzumab tetraxetan following R-CHOP in elderly patients with diffuse large B-cell lymphoma: a prospective, single group, phase 2 trial

BACKGROUND

Radioimmunotherapy represents a potential option as consolidation after chemoimmunotherapy in patients with diffuse large B-cell lymphoma who are not candidates for transplantation. We aimed to assess activity and toxicity of fractionated radioimmunotherapy using anti-CD22 ⁹⁰Y-epratuzumab tetraxetan as consolidation after front-line induction chemoimmunotherapy in untreated elderly patients with diffuse large B-cell lymphoma.

METHODS

We did a prospective, single-group, phase 2 trial at 28 hospitals in France, with patients recruited from 17 hospitals. Eligible patients were aged 60-80 years with bulky stage 2-3 or stage 3-4 CD20-positive diffuse large B-cell lymphoma, previously untreated, and not eligible for transplantation. Patients received six cycles of R-CHOP (rituximab [375 mg/m²], cyclophosphamide [750 mg/m²], doxorubicin [50 mg/m²], and vincristine [1·4 mg/m², up to 2 mg] all on day 1, and prednisone [40 mg/m²] daily for 5 days), administered every 14 days. 6-8 weeks after R-CHOP, responders received two doses of 15 mCi/m² (555 MBq/m²) ⁹⁰Y-epratuzumab tetraxetan administered 1 week apart. The primary endpoint was 2 year event-free survival in all registered eligible patients who received at least 1 day of study treatment; the safety analysis was done in the same population. This trial is registered with ClinicalTrials.gov, number NCT00906841.

FINDINGS

Between Oct 22, 2008, and Dec 16, 2010, we recruited 75 patients, of whom four (5%) were excluded after central pathology review; hence, 71 (95%) patients were included in the analysis. All patients started induction treatment; 57 (80%) received radioimmunotherapy. With a median follow-up of 37 months (IQR 30-44), the estimated 2 year event-free survival was 75% (95% CI 63-84). Radioimmunotherapy toxicity consisted of grade 3-4 thrombocytopenia in 48 (84%) of 57 patients and neutropenia in 45 (79%) of 57 patients. One patient developed myelodysplastic syndrome 28 months after receiving radioimmunotherapy and one patient developed acute myeloid leukaemia 5 months after receiving radioimmunotherapy.

INTERPRETATION

Fractionated radioimmunotherapy with ⁹⁰Y-epratuzumab tetraxetan might be appropriate for response consolidation after induction chemotherapy in older patients with advanced diffuse large B-cell lymphoma, but further comparative studies are needed.

FUNDING

Immunomedics, Amgen, Canceropôle Grand Ouest, the GOELAMS/LYSA group and the French National Agency for Research (Investissements d'Avenir).

A phenotype of atypical apraxia of speech in a family carrying SQSTM1 mutation

SQSTM1 mutations, coding for the p62 protein, were identified as a monogenic cause of Paget disease of bone and of amyotrophic lateral sclerosis. More recently, SQSTM1 mutations were identified in few families with frontotemporal dementia. We report a new family carrying SQSTM1 mutation and presenting with a clinical phenotype of speech apraxia or atypical behavioral disorders, associated with early visuo-contructional deficits. This study further supports the implication of SQSTM1 in frontotemporal dementia, and enlarges the phenotypic spectrum associated with SQSTM1 mutations.

Peripheral autonomic nervous system involvement in Gaucher-related parkinsonism

The pathological process affects the peripheral autonomic nervous system in the vast majority of sporadic PD patients. Recent reports have shown that patients with a familial form of the disease caused by mutation of the gene encoding LRRK2 and alpha-synuclein also display autonomic abnormalities, especially cardiac sympathetic denervation. In the present report, we have studied the involvement of the peripheral autonomic system in a patient with Gaucher disease-associated parkinsonism. Using colonic biopsies and quantitative 123I-MIBG scintigraphy respectively, we show that both Lewy pathology and cardiac denervation were present in this case of Gaucher-associated Parkinsonism. We discuss the consequence of these findings on the pathophysiology of the disease.

Radioimmunoconjugates for the treatment of cancer

Radioimmunotherapy (RIT) has been developed for more than 30 years. Two products targeting the CD20 antigen are approved in the treatment of non-Hodgkin B-cell lymphoma (NHBL): iodine 131-tositumomab and yttrium 90-ibritumomab tiuxetan. RIT can be integrated in clinical practice for the treatment of patients with relapsed or refractory follicular lymphoma (FL) or as consolidation after induction chemotherapy. High-dose treatment, RIT in first-line treatment, fractionated RIT, and use of new humanized monoclonal antibodies (MAbs), in particular targeting CD22, showed promising results in NHBL. In other hemopathies, such as multiple myeloma, efficacy has been demonstrated in preclinical studies. In solid tumors, more resistant to radiation and less accessible to large molecules such as MAbs, clinical efficacy remains limited. However, pretargeting methods have shown clinical efficacy. Finally, new beta emitters such as lutetium 177, with better physical properties will further improve the safety of RIT and alpha emitters, such as bismuth 213 or astatine 211, offer the theoretical possibility to eradicate the last microscopic clusters of tumor cells, in the consolidation setting. Personalized treatments, based on quantitative positron emission tomography (PET), pre-therapeutic imaging, and dosimetry procedures, also could be applied to adapt injected activity to each patient.

[Dementia: Where are the Lewy bodies?]

Dementia with Lewy bodies (DLB) is the second cause of degenerative dementia in autopsy studies. In clinical pratice however, the prevalence of DLB is much lower with important intercenter variations. Among the reasons for this low sensitivity of DLB diagnosis are (1) the imprecision and subjectivity of the diagnostic criteria; (2) the underestimation of non-motor symptoms (REM-sleep behavior disorder, dysautonomia, anosmia); mostly (3) the nearly constant association of Lewy bodies with Alzheimer's disease pathology, which dominates the clinical phenotype. With the avenue of targeted therapies against the protein agregates, new clinical scales able to apprehend the coexistence of Lewy pathology in Alzheimer's disease are expected.

Radioimmunotherapy of B-Cell Non-Hodgkin's Lymphoma

This manuscript reviews current advances in the use of radioimmunotherapy (RIT) for the treatment of B-cell non-Hodgkin's lymphoma (NHL). RIT has been in use for more than 20 years and has progressed significantly with the discovery of new molecular targets, the development of new stable chelates, the humanization of monoclonal antibodies (MAbs), and the use of pretargeting techniques. Today, two products targeting the CD20 antigen are approved: (131)I-tositumomab (Bexxar(®)), and (90)Y-ibritumomab tiuxetan (Zevalin(®)). (131)I-tositumomab is available in the United States, and (90)Y-ibritumumab tiuxetan in Europe, the United States, Asia, and Africa. RIT can be integrated in clinical practice using non-ablative activities for treatment of patients with relapsed or refractory follicular lymphoma (FL) or as consolidation after induction chemotherapy in front-line treatment in FL patients. Despite the lack of phase III studies to clearly define the efficacy of RIT in the management of B lymphoma in the era of rituximab-based therapy, RIT efficacy in NHL has been demonstrated. In relapsing refractory FL and transformed NHL, RIT as a monotherapy induces around 30% complete response with a possibility of durable remissions. RIT consolidation after induction therapy significantly improves the quality of the response. Dose-limiting toxicity of RIT is hematological, depending on bone marrow involvement and prior treatment. Non-hematological toxicity is generally low. Different studies have been published assessing innovative protocols of RIT or new indications, in particular treatment in patients with aggressive lymphomas. High-dose treatment, RIT as consolidation after different therapeutic induction modalities, RIT in first-line treatment or fractionated RIT showed promising results. New MAbs, in particular humanized MAbs, or combinations of naked and radiolabeled MAbs, also appear promising. Personalized dosimetry protocols should be developed to determine injected activity.

Vertebral osteomyelitis: an unusual presentation of Bartonella henselae infection

OBJECTIVES

To report cases of cat scratch disease with vertebral osteomyelitis.

METHODS

We describe clinical features, diagnostic, treatment, and outcome of 2 patients with vertebral osteomyelitis due to Bartonella henselae and provide a review of the relevant literature.

RESULTS

A 47-year-old man was investigated for fever, splenomegaly, and cervical adenopathy. A lymphoma was suspected on the clinical picture, the laboratory tests, and the computed tomographic scan. [(18)F]-fluoro-2-deoxy-d-glucose-positron emission tomography detected splenic nodules and a hypermetabolic focus of C7 vertebral body compatible with a vertebral osteomyelitis on magnetic resonance imaging. B henselae infection was confirmed by polymerase chain reaction performed on lymph node biopsy. A 34-year-old woman was investigated for fever and right upper quadrant abdominal pain. She had consulted 2 weeks before for a unique lesion of right index and an axillar adenopathy that have improved spontaneously. A technetium bone scan performed 1 week later because of a thoracic backache demonstrated an increased uptake of the T6 vertebra. Vertebral magnetic resonance imaging was compatible with a T6 osteomyelitis. B henselae infection was confirmed by serology (seroconversion). Both patients were treated with rifampin and doxycycline and recovered within 3 months.

CONCLUSIONS

B henselae vertebral osteomyelitis can involve immunocompetent adults. In the case of vertebral osteomyelitis with negative blood cultures, recent history of local lymphadenopathy and cat exposure must be investigated and B henselae serology must be performed. Nevertheless, even if serology is positive, vertebral biopsy is required to rule out other pathogens or malignancy. B henselae infection can be confirmed by polymerase chain reaction performed on vertebral or lymph node biopsy.