Spinocerebellar ataxia 27B (SCA27B), a frequent late-onset cerebellar ataxia

Genetic cerebellar ataxias are still a diagnostic challenge, and yet not all of them have been identified. Very recently, in early 2023, a new cause of late-onset cerebellar ataxia (LOCA) was identified, spinocerebellar ataxia 27B (SCA27B). This is an autosomal dominant ataxia due to a GAA expansion in intron 1 of the FGF14 gene. Thanks to the many studies carried out since its discovery, it is now possible to define the clinical phenotype, its particularities, and the progression of SCA27B. It has also been established that it is one of the most frequent causes of LOCA. The core phenotype of the disease consists of slowly progressive late-onset ataxia with cerebellar syndrome, oculomotor disorders including downbeat nystagmus, and episodic symptoms such as diplopia. Therapeutic approaches have been proposed, including acetazolamide, and 4-aminopyridine, the latter with a better benefit/tolerance profile.

The phase 2 LYSA study of prednisone, vinblastine, doxorubicin, and bendamustine for untreated Hodgkin lymphoma in older patients

ABSTRACT

Older patients with classical Hodgkin lymphoma (cHL) require more effective and less toxic therapies than younger patients. In this multicenter, prospective, phase 2 study, we investigated a new firstline therapy regimen comprising 6 cycles of prednisone (40 mg/m2, days 1-5), vinblastine (6 mg/m2, day 1), doxorubicin (40 mg/m2, day 1), and bendamustine (120 mg/m2, day 1) (PVAB regimen) every 21 days for patients with newly diagnosed cHL aged ≥61 years with an advanced Ann Arbor stage. A Mini Nutritional Assessment score ≥17 was the cutoff value for patients aged ≥70 years. The primary end point was the complete metabolic response (CMR) rate after 6 cycles. The median age of the 89 included patients was 68 years (range, 61-88 years), with 35 patients (39%) aged ≥70 years. Seventy-eight patients (88%) completed the 6 cycles. The toxicity rate was acceptable, with a 20% rate of related serious adverse events. CMR was achieved by 69 patients (77.5%; 95% confidence interval [CI], 67-86). After a median follow-up of 42 months, 31 patients progressed or relapsed (35%), and 24 died (27%) from HL (n = 11), toxicity during treatment (n = 4), secondary cancers (n = 6), or other causes (n = 3). The 4-year progression-free survival (PFS) and overall survival rates were 50% and 69%, respectively. Multivariate analysis showed that liver involvement (P = .001), lymphopenia (P = .001), CRP (P = .0005), and comedications (P = .003) were independently associated with PFS. The PVAB regimen yielded a high CMR rate with acceptable toxicity. Over long-term follow-up, survival end points were influenced by unrelated lymphoma events. This trial was registered at www.clinicaltrials.gov as #NCT02414568 and at EudraCT as 2014-001002-17.

Megalencephaly secondary to a novel germline missense variant p.Asp322Tyr in AKT3 associated with growth hormone deficiency and central hypothyroidism: A case report

Germline gain of function variations in the AKT3 gene cause brain overgrowth syndrome with megalencephaly and diffuse bilateral cortical malformations. Here we report a child with megalencephaly, who is a carrier of a novel heterozygous missense variant in the AKT3 gene NM_005465.7:c.964G>T,p.Asp322Tyr. The phenotype of this patient is associated with pituitary deficiencies diagnosed at 2 years of age: growth hormone (GH) deficiency responsible for growth delay and central hypothyroidism. After 6 months of GH treatment, intracranial hypertension was noted, confirmed by the observation of papilledema and increased intracranial pressure, requiring the initiation of acetazolamide treatment and the discontinuation of GH treatment. This is the second reported patient described with megalencephaly and AKT3 gene variant associated with GH deficiency . Other endocrine disorders have also been reported in few cases with hypothyroidism and hypoglycemia. Pituitary deficiency may be a part of the of megalencephaly phenotype secondary to germline variant in the AKT3 gene. Special attention should be paid to growth in these patients and search for endocrine deficiency is necessary in case of growth retardation or hypoglycemia.

Salvage therapy with brentuximab-vedotin and bendamustine for patients with R/R PTCL: a retrospective study from the LYSA group

Patients with relapsed or refractory (R/R) peripheral T-cell lymphomas (PTCL) have a poor prognosis. Bendamustine (B) and brentuximab-vedotin (Bv) have shown interesting results in this setting. However, little information is available about their efficacy in combination. This multicenter and retrospective study aimed to evaluate the efficacy and safety of the combination of BBv in patients with noncutaneous R/R PTCL among 21 LYSA centers in France and Belgium. The primary objective was the overall response rate. A total of 82 patients with R/R PTCL were included. The best overall response rate (ORR) was 68%, with 49% of patients in complete response (CR). In multivariable analysis, only the disease status after the last regimen (relapse vs refractory) was associated with the response with an ORR of 83% vs 57%. Median duration of response was 15.4 months for patients in CR. With a median follow-up of 22 months, the median progression free survival (PFS) and overall survival (OS) were 8.3 and 26.3 months respectively. Moreover, patients in CR, who underwent an allogeneic transplant, had a better outcome than patients who did not with a median PFS and OS of 19.3 vs 4.8 months and not reached vs 12.4 months, respectively. Fifty-nine percent of patients experienced grade 3/4 adverse events that were mainly hematologic. BBv is highly active in patients with R/R PTCL and should be considered as a one of the best options of immunochemotherapy salvage combination in this setting and particularly as a bridge to allogeneic transplant for eligible patients.

ENPP1 homozygous stop-loss variant causing generalized arterial cal cifications of infancy: About a severe neonatal clinical case

Generalized Arterial Calcifications of Infancy (GACI) is an extremely rare autosomal recessive genetic condition, mostly due to pathogenic variations in the ENPP1 gene (GACI1, MIM # 208000, ENPP1, MIM *173335). To date 46 likely pathogenic or pathogenic distinct variations in ENPP1 have been described, including nonsense, frameshift, missense, splicing variations, and large deletions. Here we report a case of GACI in a male newborn with a homozygous stop-loss variant in ENPP1 treated in Nancy Regional University Maternity Hospital. Based on proband main clinical signs, clinical exome sequencing was performed and showed a deletion of one nucleotide leading to frameshift and stop-loss (NM_006208.3 (ENPP1):c.2746del,p.(Thr916Hisfs*23)). Clinical presentation is characterized by primary neonatal arterial hypertension resulting in hypertrophic cardiomyopathy decompensated by three cardiogenic shocks and a neonatal deep right sylvian stroke. The child died at 24 days of life. This is the first report of a pathogenic stop-loss variant in ENPP1. It is an opportunity to remind clinicians of GACI disease, a rare and severe etiology in neonates with severe hypertension, and possibility of bisphosphonates therapy.

ALK-negative anaplastic large cell lymphoma with DUSP22 rearrangement has distinctive disease characteristics with better progression-free survival: a LYSA study

ALK-negative anaplastic large cell lymphoma (ALCL) comprises subgroups harboring rearrangements of DUSP22 (DUSP22- R) or TP63 (TP63-R). Two studies reported 90% and 40% 5-year overall survival (OS) rates in 21 and 12 DUSP22-R/TP63- not rearranged (NR) patients, respectively, making the prognostic impact of DUSP22-R unclear. Here, 104 newly diagnosed ALK-negative ALCL patients (including 37 from first-line clinical trials) from the LYSA TENOMIC database were analyzed by break-apart fluorescence in situ hybridization assays for DUSP22-R and TP63-R. There were 47/104 (45%) DUSP22-R and 2/93 (2%) TP63-R cases, including one DUSP22-R/TP63-R case. DUSP22-R tumors more frequently showed CD3 expression (62% vs. 35%, P=0.01), and less commonly a cytotoxic phenotype (27% vs. 82%; P<0.001). At diagnosis, DUSP22- R ALCL patients more frequently had bone involvement (32% vs. 13%, P=0.03). The patient with DUSP22-R/TP63-R ALCL had a rapidly fatal outcome. After a median follow-up of 4.9 years, 5-year progression-free survival (PFS) and OS rates of 84 patients without TP63-R treated with curative-intent anthracycline-based chemotherapy were 41% and 53%, respectively. According to DUSP22 status, 5-year PFS was 57% for 39 DUSP22-R versus 26% for 45 triple-negative (DUSP22-NR/TP63-NR/ALK-negative) patients (P=0.001). The corresponding 5-year OS rates were 65% and 41%, respectively (P=0.07). In multivariate analysis, performance status and DUSP22 status significantly affected PFS, and distinguished four risk groups, with 4-year PFS and OS ranging from 17% to 73% and 21% to 77%, respectively. Performance status but not DUSP22 status influenced OS. The use of brentuximab vedotin in relapsed/refractory patients improved OS independently of DUSP22 status. Our findings support the biological and clinical distinctiveness of DUSP22- R ALK-negative ALCL. Its relevance to outcome in patients receiving frontline brentuximab vedotin remains to be determined.

Brentuximab Vedotin Plus AVD for First-Line Treatment of Early-Stage Unfavorable Hodgkin Lymphoma (BREACH): A Multicenter, Open-Label, Randomized, Phase II Trial

PURPOSE

The prognosis of patients with early-stage unfavorable Hodgkin lymphoma remains unsatisfactory. We assessed the efficacy and safety of brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine (BV-AVD) in previously untreated, early-stage unfavorable Hodgkin lymphoma (ClinicalTrials.gov identifier: NCT02292979).

METHODS

BREACH is a multicenter, randomized, open-label, phase II trial. Eligible patients were age 18-60 years with ≥ 1 unfavorable EORTC/LYSA criterion. Patients were randomly assigned (2:1) to four cycles of BV-AVD or standard doxorubicin, bleomycin, vincristine, and dacarbazine (ABVD), followed by 30 Gy involved node radiotherapy. The primary end point was the positron emission tomography (PET) response rate after two cycles by expert independent review using the Deauville score. The study was designed to test if the PET-negative rate after two cycles of BV-AVD was superior to 75%. We hypothesized a 10% increase in the PET-negative rate after two cycles of BV-AVD.

RESULTS

Between March 2015 and October 2016, 170 patients were enrolled. After two cycles, the primary end point of the study was met: 93 (82.3%; 90% CI, 75.3 to 88.0) of 113 patients in the BV-AVD arm were PET-negative (Deauville score 1-3) compared with 43 (75.4%; 90% CI, 64.3% to 84.5%) of 57 in the ABVD arm. The 2-year progression-free survival (PFS) was 97.3% (95% CI, 91.9 to 99.1) and 92.6% (95% CI, 81.4% to 97.2%) in the BV-AVD and ABVD arms, respectively. High total metabolic tumor volume was associated with a significantly shorter PFS (hazard ratio, 17.9; 95% CI, 2.2 to 145.5; P < .001). For patients with high total metabolic tumor volume, the 2-year PFS rate was 90.9% (95% CI, 74.4 to 97.0) and 70.7% (95% CI, 39.4% to 87.9%) in the BV-AVD and ABVD arms, respectively.

CONCLUSION

BV-AVD demonstrated an improvement in the PET-negative rate compared with ABVD after two cycles.

Distinction of Lymphoma from Sarcoidosis on 18F-FDG PET/CT: Evaluation of Radiomics-Feature-Guided Machine Learning Versus Human Reader Performance

Sarcoidosis and lymphoma often share common features on ¹⁸F-FDG PET/CT, such as intense hypermetabolic lesions in lymph nodes and multiple organs. We aimed at developing and validating radiomics signatures to differentiate sarcoidosis from Hodgkin lymphoma (HL) and diffuse large B-cell lymphoma (DLBCL). Methods: We retrospectively collected 420 patients (169 sarcoidosis, 140 HL, and 111 DLBCL) who underwent pretreatment ¹⁸F-FDG PET/CT at the University Hospital of Liege. The studies were randomly distributed to 4 physicians, who gave their diagnostic suggestion among the 3 diseases. The individual and pooled performance of the physicians was then calculated. Interobserver variability was evaluated using a sample of 34 studies interpreted by all physicians. Volumes of interest were delineated over the lesions and the liver using MIM software, and 215 radiomics features were extracted using the RadiomiX Toolbox. Models were developed combining clinical data (age, sex, and weight) and radiomics (original and tumor-to-liver TLR radiomics), with 7 different feature selection approaches and 4 different machine-learning (ML) classifiers, to differentiate sarcoidosis and lymphomas on both lesion-based and patient-based approaches. Results: For identifying lymphoma versus sarcoidosis, physicians' pooled sensitivity, specificity, area under the receiver-operating-characteristic curve (AUC), and accuracy were 0.99 (95% CI, 0.97-1.00), 0.75 (95% CI, 0.68-0.81), 0.87 (95% CI, 0.84-0.90), and 89.3%, respectively, whereas for identifying HL in the tumor population, it was 0.58 (95% CI, 0.49-0.66), 0.82 (95% CI, 0.74-0.89), 0.70 (95% CI, 0.64-0.75) and 68.5%, respectively. Moderate agreement was found among observers for the diagnosis of lymphoma versus sarcoidosis and HL versus DLBCL, with Fleiss κ-values of 0.66 (95% CI, 0.45-0.87) and 0.69 (95% CI, 0.45-0.93), respectively. The best ML models for identifying lymphoma versus sarcoidosis showed an AUC of 0.94 (95% CI, 0.93-0.95) and 0.85 (95% CI, 0.82-0.88) in lesion- and patient-based approaches, respectively, using TLR radiomics (plus age for the second). To differentiate HL from DLBCL, we obtained an AUC of 0.95 (95% CI, 0.93-0.96) in the lesion-based approach using TLR radiomics and 0.86 (95% CI, 0.80-0.91) in the patient-based approach using original radiomics and age. Conclusion: Characterization of sarcoidosis and lymphoma lesions is feasible using ML and radiomics, with very good to excellent performance, equivalent to or better than that of physicians, who showed significant interobserver variability in their assessment.

Nodal cytotoxic peripheral T-cell lymphoma occurs frequently in the clinical setting of immunodysregulation and is associated with recurrent epigenetic alterations

Nodal peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) with cytotoxic phenotype is overall rare, with most reports coming from Asia. Given its elusive pathobiology, we undertook a clinicopathological and molecular study of 54 Western patients diagnosed with PTCL, NOS expressing cytotoxic molecules, within a lymph node. More commonly males (M/F-2,6/1) with median age of 60 years were affected. Besides lymphadenopathy, 87% of patients had ≥1 involved extranodal site. High-stage disease (III-IV), International Prognostic Index >2, B symptoms, LDH level, and cytopenia(s) were observed in 92, 63, 67, 78, and 66% of cases, respectively. Ten patients had a history of B-cell malignancies, one each of myeloid neoplasm, breast or prostate cancer, and 4 others had underlying immune disorders. Most patients (70%) died, mostly of disease, with a median overall survival of 12.7 months. Immunophenotypically, the neoplastic lymphocytes were T-cell receptor (TCR) αβ + (47%), TCR-silent (44%) or TCRγδ+ (10%), commonly CD8 + (45%) or CD4-CD8- (32%). All except one had an activated cytotoxic profile, and 95% were subclassified into PTCL-TBX21 subtype based on CXCR3, TBX21, and GATA3 expression pattern. Seven patients (13%) disclosed EBER + tumor cells. Targeted DNA deep-sequencing (33 cases) and multiplex ligation-dependent reverse transcription-polymerase chain reaction assay (43 cases) identified frequent mutations in epigenetic modifiers (73%), including TET2 (61%) and DNMT3A (39%), recurrent alterations affecting the TCR (36%) and JAK/STAT (24%) signaling pathways and TP53 mutations (18%). Fusion transcripts involving VAV1 were identified in 6/43 patients (14%). Patients with nodal cytotoxic PTCL, NOS have an aggressive behavior and frequently present in a background of impaired immunity, although the association with Epstein-Barr virus is rare. The recurrent alterations in genes involved in DNA methylation together with genes related to cytokine or TCR signaling, suggest that co-operation of epigenetic modulation with cell-signaling pathways plays a critical role in the pathogeny of these lymphomas.

Monomorphic epitheliotropic intestinal T-cell lymphoma comprises morphologic and genomic heterogeneity impacting outcome

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare aggressive T-cell lymphoma most reported in Asia. We performed a comprehensive clinical, pathological and genomic study of 71 European MEITL patients (36 males, 35 females, median age 67 years). The majority presented with gastrointestinal involvement and had emergency surgery, and 40% had stage IV disease. The tumors were morphologically classified into two groups: typical (58%) and atypical (i.e., non-monomorphic or with necrosis, angiotropism or starry-sky pattern) (42%), sharing a homogeneous immunophenotypic profile (CD3+ [98%] CD4- [94%] CD5- [97%] CD7+ [97%] CD8+ [90%] CD56+ [86%] CD103+ [80%] cytotoxic marker+ [98%]) with more frequent expression of TCRgd (50%) than TCRab (32%). MYC expression (30% of cases) partly reflecting MYC gene locus alterations, correlated with non-monomorphic cytology. Almost all cases (97%) harbored deleterious mutation(s) and/or deletion of the SETD2 gene and 90% had defective H3K36 trimethylation. Other frequently mutated genes were STAT5B (57%), JAK3 (50%), TP53 (35%), JAK1 (12.5%), BCOR and ATM (11%). Both TP53 mutations and MYC expression correlated with atypical morphology. The median overall survival (OS) of 63 patients (43/63 only received chemotherapy after initial surgery) was 7.8 months. Multivariate analysis found a strong negative impact on outcome of MYC expression, TP53 mutation, STAT5B mutation and poor performance status while aberrant B-cell marker expression (20% of cases) correlated with better survival. In conclusion, MEITL is an aggressive disease with resistance to conventional therapy, predominantly characterized by driver gene alterations deregulating histone methylation and JAK/STAT signaling and encompasses genetic and morphologic variants associated with very high clinical risk.

Extracellular miR-6723-5p could serve as a biomarker of limbal epithelial stem/progenitor cell population

BACKGROUND

Dysfunction or loss of limbal stem cells can result in limbal stem cell deficiency (LSCD), a disease that cause corneal opacity, pain, and loss of vision. Cultivated limbal epithelial transplantation (CLET) can be used to restore stem cell niche homeostasis and replenish the progenitor pool. Transplantation has been reported with high success rate, but there is an unmet need of prognostic markers that correlate with clinical outcomes. To date, the progenitor content in the graft is the only parameter that has been retrospectively linked to success.

METHODS

In this study, we investigate extracellular micro RNAs (miRNAs) associated with stem/progenitor cells in cultivated limbal epithelial cells (cLECs). Using micro RNA sequencing and linear regression modelling, we identify a miRNA signature in cultures containing high proportion of stem/progenitor cells. We then develop a robust RNA extraction workflow from culture media to confirm a positive miRNA correlation with stem/progenitor cell proportion.

RESULTS

miR-6723-5p is associated with cultures containing high proportion of stem/progenitor cells, and is detected in the basal layer of corneal epithelium.

CONCLUSIONS

These results indicate that miR-6723-5p could potentially serve as a stem/progenitor cell marker in cLECs.

Positron Emission Tomography-Driven Strategy in Advanced Hodgkin Lymphoma: Prolonged Follow-Up of the AHL2011 Phase III Lymphoma Study Association Study

PURPOSE

The AHL2011 study (ClinicalTrials.gov identifier: NCT01358747) demonstrated that a positron emission tomography (PET)-driven de-escalation strategy after two cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) provides similar progression-free survival (PFS) and overall survival (OS) and reduces early toxicity compared with a nonmonitored standard treatment. Here, we report, with a prolonged follow-up, the final study results.

METHODS

Patients with advanced Hodgkin lymphoma (stage III, IV, or IIB with mediastinum/thorax ratio > 0.33 or extranodal involvement) age 16-60 years were prospectively randomly assigned between 6 × BEACOPP and a PET-driven arm after 2 × BEACOPP delivering 4 × ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) in PET2- and 4 × BEACOPP in PET2+ patients. PET performed after four cycles of chemotherapy had to be negative to complete the planned treatment.

RESULTS

In total, 823 patients were enrolled including 413 in the standard arm and 410 in the PET-driven arm. With a 67.2-month median follow-up, 5-year PFS (87.5% v 86.7%; hazard ratio [HR] = 1.07; 95% CI, 0.74 to 1.57; P = .67) and OS (97.7% in both arms; HR = 1.012; 95% CI, 0.50 to 2.10; P = .53) were similar in both randomization arms. In the whole cohort, full interim PET assessment predicted patients' 5-year PFS (92.3% in PET2-/PET4-, 75.4% [HR = 3.26; 95% CI, 18.3 to 5.77] in PET2+/PET4- and 46.5% [HR = 12.4; 95% CI, 7.31 to 19.51] in PET4+ patients, respectively; P < .0001) independent of international prognosis score. Five-year OS was also affected by interim PET results, and PET2+/PET4- patients (93.5%; HR = 3.3; 95% CI, 1.07 to 10.1; P = .036) and PET4+ patients (91.9%; HR = 3.756; 95% CI, 1.07 to 13.18; P = .038) had a significant lower OS than PET2-/PET4- patients (98.2%). Twenty-two patients (2.7%) developed a second primary malignancy, 13 (3.2%) and 9 (2.2%) in the standard and experimental arms, respectively.

CONCLUSION

The extended follow-up confirms the continued efficacy and favorable safety of AHL2011 PET-driven strategy, which is noninferior to standard six cycles of BEACOPP. PET4 provides additional prognostic information to PET2 and allows identifying patients with particularly poor prognosis.

[Systematic karyotyping before ICSI: A necessary procedure? Analysis of case studies in the Nancy University Hospital Fertility Centre]

INTRODUCTION

A constitutional karyotype is often assayed for the couple before ICSI management. The objective of this study was to assess the prevalence of chromosomal abnormality in an infertile population, the impact on the care of couples and its cost.

METHODS

A single-center retrospective study was carried out at the Fertility Center of the University Hospital of Nancy, including all infertile couples who underwent a karyotype analysis from June 2009 to December 2016.

RESULTS

1252 couples were included. 7.9% had at least one abnormal karyotype. A change in care affected 22% of these couples, i.e. 1.7% of the total population. 9% of couples with karyotype abnormality underwent PGD. In the male population, the percentage of abnormal spermograms is significantly higher in the group with karyotype abnormality compared to the control group (85.7% vs. 46.5%, P<0.001).

DISCUSSION

The constitutional karyotype, due to its high economic and human cost, and limited interest, is a screening method for chromosomal abnormalities that has no place systematically before performing IVF. The future lies in the restriction of the indications for prescribing the karyotype as well as in the realization of PGS in targeted situations.

Patient education program at the forefront of cancer-associated thrombosis care

INTRODUCTION

Treatment of cancer-associated thrombosis (CAT) requires specific approaches, although it is well codified in most cases. Current national and international (International Initiative on Cancer and Thrombosis, ITAC) Clinical Practice Guidelines (CPG) recommend the use of low-molecular-weight heparin (LMWH) over 6 months as first treatment option, and anticoagulation should be maintained thereafter as long as cancer is active. Since compliance improves when patients understand their disease and related treatments, we created a dedicated patient education program (PEP) for CAT, aiming to improve quality of care.

METHODS

Retrospective analysis of all patients who voluntarily joined the PEP for CAT from 2014 to 2020.

RESULTS

In total, 182 cancer patients (median age, 64.9 years) were included, 53.3% with metastatic disease. A total of 528 PEP sessions (median, 3 per patient) were delivered. After PEP completion, the rate of self-injections or those performed at home by a relative had increased from 49.1% to 59.8% (P=0.05). Quality of life had improved significantly (P=0.025) and 90.0% of patients reported adhering to anticoagulant therapy.

CONCLUSION

Implementation of a structured and personalized PEP for CAT is feasible, allowing to improve cancer patient empowerment, adherence to CAT treatment and quality of life. The Groupe francophone et cancer (GFTC) members aim at facilitating access to CAT-PEP for both patients and caregivers and use of the multi-language ITAC-CPG mobile app (free access: www.itaccme.com) to improve the care and quality of life of patients with CAT.

Deep-Learning Assessed Muscular Hypodensity Independently Predicts Mortality in DLBCL Patients Younger Than 60 Years

Simple Summary

Cachexia is a major cause of mortality in cancer patients and is characterized by a continuous skeletal muscle loss. Muscle depletion assessed by computed tomography (CT) is a predictive marker in solid tumors but has never been assessed in non-Hodgkin’s lymphoma. Despite software improvements, its measurement remains highly time-consuming and cannot be performed in clinical practice. We report the development of a CT segmentation algorithm based on convolutional neural networks. It automates the extraction of anthropometric data from pretherapeutic CT to assess precise body composition of young diffuse large B cell lymphoma (DLBCL) patients at the time of diagnosis. In this population, muscle hypodensity appears to be an independent risk factor for mortality, and can be estimated at diagnosis with this new tool.

Abstract

Background. Muscle depletion (MD) assessed by computed tomography (CT) has been shown to be a predictive marker in solid tumors, but has not been assessed in non-Hodgkin’s lymphomas. Despite software improvements, MD measurement remains highly time-consuming and cannot be used in clinical practice. Methods. This study reports the development of a Deep-Learning automatic segmentation algorithm (DLASA) to measure MD, and investigate its predictive value in a cohort of 656 diffuse large B cell lymphoma (DLBCL) patients included in the GAINED phase III prospective trial (NCT01659099). Results. After training on a series of 190 patients, the DLASA achieved a Dice coefficient of 0.97 ± 0.03. In the cohort, the median skeletal muscle index was 50.2 cm²/m² and median muscle attenuation (MA) was 36.1 Hounsfield units (HU). No impact of sarcopenia was found on either progression free survival (PFS) or overall survival (OS). Muscular hypodensity, defined as MA below the tenth percentile according to sex, was associated with a lower OS and PFS, respectively (HR = 2.80 (95% CI 1.58–4.95), p < 0.001, and HR = 2.22 (95% CI 1.43–3.45), p < 0.001). Muscular hypodensity appears to be an independent risk factor for mortality in DLBCL and because of DLASA can be estimated in routine practice.

[Diffuse large B-cell lymphoma: a revolutionary treatment based on genetically-modified immune cells called CAR T cells]

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma. Firstline immunochemotherapy cures approximatively 60 % of patients. The prognosis of patients with refractory disease or with relapsed disease within the first two years after the end of treatment is highly unfavourable. Since June 2019, a new third-line treatment with CAR T cells (chimeric antigen receptor T cells) seems to completely modify the prognosis of these patients. A significant proportion of long-lasting complete responses is obtained with this revolutionary treatment. Quick specialized intervention is required for the unique side effects of this therapy.

[Management of mycosis fungoide : focus on brentuximab vedotin]

Recently, brentuximab vedotin (BV) (Adcetris®) obtained the reimbursement in Belgium for the treatment of the primary cutaneous NKT-cell lymphomas mycosis fungoides (MF), large cell anaplastic lymphoma and lymphomatoid papulosis type A. BV is a monoclonal antibody directed against the CD30 expressed on tumoral T cells. The inhibition of this pathway releases the process of apoptosis leading to the cell death of the tumoral cells. BV is reimbursed after the use of another systemic treatment without success and if the number of CD30 positive atypical T-cells is larger than 10 %. BV is administered intravenously every 3 weeks with a dosing of 1,8 mg/kg with a maximum of 16 courses. The response rates exceed 75 %. In some instances, interesting treatment responses have been observed with BV in CD30 negative patients. The principal adverse effects are neutropenia and peripheral neuropathy. Two patients are presented with longstanding multi-resistant MF that were successfully treated with BV.

Patients' perception of the open-space operating hall for cataract surgery

PURPOSE

To assess the perception of patients undergoing cataract surgery under topical anesthesia in an open-space operating hall.

METHODS

The study was set in the department of ophthalmology, Cochin Paris Descartes University Hospital, in a newly built open-space operating hall dedicated to ophthalmic surgery. It was a prospective study of consecutive patients undergoing cataract surgery by 11 surgeons. Our population study comprised 250 patients operated in an open-space operating hall with 3 surgical areas. Only first-eye standard cataract surgeries performed under topical anesthesia were included. Responses to a face-to-face questionnaire administered by a single interviewer to patients before their discharge on the day of their surgery were analyzed.

RESULTS

Fifty-two patients (21%) knew beforehand that their procedure would take place in an open-space operating hall, 118 (47%) realized that they were in such an environment on the occasion of their surgery and 80 (32%) did not notice. Conversations and noises unrelated to their own surgeries were overheard respectively by 15 (6%) and 37 (15%) patients. Of the 250 patients, 237 (95%) did not report any discomfort associated with the fact that their procedure had been performed in an open-space operating hall.

CONCLUSIONS

Cataract surgery performed in an open-space setting did not seem to affect the patients' comfort during the procedure.

[An illustrative case of the POEMS syndrome]

POEMS syndrome is a rare and invalidating entity characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and dermatoses. The diagnosis of this condition is often late and challenging due to the heterogeneity of clinical forms. The light chains secreted by the clonal plasmocytes cause overproduction of VEGF (Vascular Endothelial Growth Factor) responsible for the appearance of the clinical manifestations of POEMS. The diagnostic approach is based on different clinical and biological criteria. Patients with a solitary plasmacytoma are candidates for radiotherapy treatment. Patients with diffuse bone involvement or bone marrow infiltration are best treated by systemic drugs. The response to treatment may take several months before clinical and biological improvement. Early diagnosis and dedicated management limit the clinico-functional impact of POEMS.

Subcutaneous Rituximab-MiniCHOP Compared With Subcutaneous Rituximab-MiniCHOP Plus Lenalidomide in Diffuse Large B-Cell Lymphoma for Patients Age 80 Years or Older

PURPOSE

The prognosis of elderly patients with diffuse large B-cell lymphoma (DLBCL) is worse than that of young patients. An attenuated dose of chemotherapy-cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab (R-miniCHOP)-is a good compromise between efficacy and safety in very elderly patients. In combination with R-CHOP (R2-CHOP), lenalidomide has an acceptable level of toxicity and may mitigate the negative prognosis of the non-germinal center B-cell-like phenotype. The Lymphoma Study association conducted a multicentric, phase III, open-label, randomized trial to compare R-miniCHOP and R2-miniCHOP.

PATIENTS AND METHODS

Patients of age 80 years or older with untreated DLBCL were randomly assigned into the R-miniCHOP21 group or the R2-miniCHOP21 group for six cycles and stratified according to CD10 expression and age. The first cycle of rituximab was delivered by IV on D1 after a prephase and then delivered subcutaneously on D1 of cycles 2-6. Lenalidomide was delivered at a dose of 10 mg once daily on D1-D14 of each cycle. The primary end point was overall survival (OS).

RESULTS

A total of 249 patients with new DLBCL were randomly assigned (127 R-miniCHOP and 122 R2-miniCHOP). The median age was 83 years (range, 80-96), and 55% of the patients were classified as non-GCB. The delivered dose for each R-miniCHOP compound was similar in both arms. Over a median follow-up of 25.1 months, the intention-to-treat analysis revealed that R2-miniCHOP did not improve OS (2-year OS 66% in R-miniCHOP and 65.7% in R2-miniCHOP arm, P = .98) in the overall population or in the non-GCB population. Grade 3-4 adverse events occurred in 53% of patients with R-miniCHOP and in 81% of patients with R2-miniCHOP.

CONCLUSION

The addition of lenalidomide to R-miniCHOP does not improve OS. Rituximab delivered subcutaneously was safe in this population.

Les effets narratifs de l’art pictural auprès du proche aidant en psycho-oncologie

Objectif : Cette étude qualitative vise à décrire les effets narratifs d’un protocole d’accompagnement psychooncologique s’appuyant sur les productions picturales d’une proche aidante (Mme Rose, 70 ans) accompagnant son mari atteint d’un cancer incurable.

Matériel et méthode : Il s’agit d’un protocole autour de la figuration picturale de la proche aidante composé de quatre étapes (temps) : l’entretien préliminaire (T1), une première rencontre autour de la création picturale (T2), une seconde rencontre d’approfondissement autour de la création picturale (T3), l’entretien final (T4). Nous avons utilisé le logiciel T-LAB 9.1.3 pour le calcul des associations de mots (cooccurrences) et réalisé une interprétation du récit selon l’approche humaniste/existentielle.

Résultats : Ce dispositif de recherche a permis de montrer les effets narratifs avant et après le travail artistique sur les problématiques psychiques inhérentes au vécu du proche aidant et notamment sur l’angoisse de mort. La dimension romantique du récit semble pouvoir supporter la narration tragique de Mme Rose.

Conclusion : Le « travail psychique avec la production picturale » peut permettre au proche aidant de mettre en figure l’amour et la mort à travers une narration personnelle empruntant à l’univers narratif du romantisme ses enjeux existentiels.

How to treat venous thromboembolism (TVE) in cancer patients: ten years of multidisciplinary team meetings (MDTM) at Saint-Louis Hospital

BACKGROUND

- The management of venous thromboembolism (VTE) is particularly challenging in patients with cancer who undergo complex treatment protocols. Cancer patients often have comorbidities which may affect the efficacy and safety of anticoagulant treatments. Coordinated multidisciplinary management of these complex cases can help optimize delivery of individualized anticoagulant treatment.

AIMS

- To describe the multidisciplinary team meeting (MDTM) for the management of VTE in cancer patients at our institution and to document outcomes in these patients.

METHODS

- Bi-monthly MDTMs attended by different physicians and nurses were established at Saint-Louis Hospital in 2008. We performed a retrospective analysis of all cases discussed between September 2008 and January 2018.

RESULTS

- Over a 10-year period, 520 patients were discussed a total of 551 times. Their mean age was 63 years with 278 (53%) women. The most frequent primary cancer sites were breast (23%), genitourinary (21 %), hematological (20%), digestive (15%), and lung (9%). Fifty-two percent of patients had metastatic cancer, and 54% of them were receiving chemotherapy. The optimal treatment for pulmonary embolism (17%), deep vein thrombosis (16%), catheter-related thrombosis (20%) or combined events (46%) was discussed. Twenty-three patients (4.4%) were discussed for one VTE recurrence and 4 (0.8%) for 2 recurrences.

CONCLUSIONS

- A dedicated MDTM for the management of VTE in cancer patients allows to discuss a wide range of clinical scenarios and contributes to optimal adherence to evidence-based clinical practices guidelines. The MDTM evaluation was successfully carried out within a short time-frame of VTE diagnosis and helped optimize individualized treatment plans.

Drug-drug interaction (DDI) with direct oral anticoagulant (DOAC) in patients with cancer

Cancer-associated thrombosis (CAT) is the second leading cause of death in cancer patients after tumor progression. The treatment of CAT is challenging because of a high risk of VTE recurrence, a high risk of bleeding, common presence of comorbidities, poly-medication, and potential drug-drug interactions (DDI). Since 2018, direct oral anticoagulants (DOACs) represent a promising therapeutic alternative and have been recently included into the 2019 update of the International Initiative on Thrombosis and Cancer (ITAC-CME) clinical practice guidelines for management of CAT. However, pharmacokinetic studies suggest that concomitant treatment with P-gp or CYP3A4 inhibitors will result in an increased exposure to rivaroxaban and apixaban, but the clinical relevance of these studies is unknown. In addition, there is an important inter-individual variability in drug absorption, distribution, metabolism and elimination, even more in cancer patients. Overall, the risk of pharmacokinetic DDI should be estimated based on several individual (patient age, renal and liver function, number of comedications) and diseases-related factors, including inflammation, sarcopenia, and low body weight. In this context, DDI with clinical implications could be expected with anti-neoplastic agents or supportive care treatments, especially with drugs known to be moderate or strong inhibitors/inducers of CYP3A4 and P-gp. Consequently, in the presence of potential DDIs through CYP3A4, and/or P-gp, LMWHs remain the first-line anticoagulant of choice for the long-term treatment of CAT. Multidisciplinary consultation meetings and therapeutic patient education should be emphasized in the complex management of CAT.

[Uveitis: Diagnosis and work-up]

Uveitis is an inflammation of the uveal tissue: iris, ciliary body and choroid. The annual incidence of uveitis in France is low (17/100,000), but visual and therapeutic consequences may be severe. Etiologic investigation is thus a fundamental step in the management of any uveitis. The history plays an important role in the initial evaluation; it must be methodic. The ophthalmologic examination seeks to classify the uveitis by type (granulomatous or not), location (anterior, intermediate or posterior), severity, duration and recurrence. Systemic signs often orient the diagnosis toward a specific cause. The diagnostic approach to uveitis relies on the history, ophthalmologic examination and evaluation of possible extraocular manifestations. Ancillary testing must be prescribed based on the clinical differential diagnosis, without which their yield is very low.

Tobacco smoking in pregnant women: fifty years of evolution in France

Background

Smoking during pregnancy is a major modifiable risk factor for maternal and foetal morbidity. We aimed to describe 1/smoking trends in France between 1972 and 2016, 2/ the factors associated with smoking cessation and reduction during pregnancy in 2016.

Methods

French National Perinatal Surveys are routine surveys based on a representative sample of births (N = 11,733 in 2016). Data were collected in face-to-face interviews in postnatal wards and from the mother’s medical record. Smoking rates before pregnancy and during 3rd trimester were estimated for each study year and characteristics associated with smoking reduction (relative percent change in number of cigarettes smoked before and during pregnancy &lt;50% or ≥ 50%) compared with smoking cessation were analysed using multinomial logistic regression.

Results

After significantly decreasing from 1995 onwards, smoking prevalence stagnates since 2010 both before pregnancy and in the 3rd trimester (30.1% and 16.2%, respectively in 2016). In 2016, 45.8% ceased smoking during pregnancy, 37.2% reduced by ≥ 50% their consumption and 16.9% reduced by &lt; 50% or did not reduce at all. The more cigarettes women smoked before pregnancy, the greater this reduction was (p &lt; 0,001). Moderate reduction (&lt;50%) vs stopping was more frequent in multiparae compared to nulliparae (aOR=2,47 [IC95%:1,93-3,15]) and in women with low education (aOR(&lt;High school vs university graduates)=7,20 [4,78-10,82]) and low income (aOR(&lt;1500€per month/&gt;3000€)=2,30 [1,51-3,50]).

Conclusions

Smoking rates were high before and during pregnancy in France in 2016. Socio-demographic factors should be considered when targeting women most at risk of continuing smoking during pregnancy.

Key messages

After significantly decreasing from 1995 onwards, smoking prevalence stagnates since 2010 both before pregnancy and in the 3rd trimester in France. Supporting female smokers of childbearing age in their attempts to quit and remain non-smokers even after pregnancy is crucial, especially in multiparae and women in poor social condition.

Hybrid Double-Chain Maltose-Based Detergents: Synthesis and Colloidal and Biochemical Evaluation

Four hybrid double-chain surfactants with a maltose polar head were synthesized. The apolar domain consists of a hydrogenated chain, and a partially fluorinated chain made of a propyl hydrogenated spacer terminated by a perfluorinated core of various lengths. Their water solubility was found to be lower than 1 g/L irrespective of the length of both chains. The self-assembling properties of pure hybrids in water were studied by dynamic light scattering and transmission electron microscopy, which revealed the formation of two populations of aggregates with diameters of 8-50 nm and 80-300 nm. When mixed with the classical detergent n-dodecylmaltoside (DDM), the four hybrids were well soluble and formed small mixed micelles. DDM/hybrid mixtures were further evaluated for the extraction of the full-length, wild-type human GPCR adenosine receptor (A_2AR), and the bacterial transporter AcrB. The solubilization of A_2AR showed extraction efficiencies ranging from 40 to 70%, while that of AcrB reached 60-90%. Finally, three of the hybrids exhibited significant thermostabilization when present as additives. The derivative with a C₁₂-hydrogenated chain and a C₄F₉-fluorinated chain emerged as the most potent additive exhibiting both good extraction yields of A_2AR and AcrB and thermostabilization of A_2AR by ∼7 °C.

Obinutuzumab combined with lenalidomide for relapsed or refractory follicular B-cell lymphoma (GALEN): a multicentre, single-arm, phase 2 study

BACKGROUND

Lenalidomide plus rituximab is approved to treat patients with relapsed or refractory follicular lymphoma. Obinutuzumab has been shown to enhance antibody-dependent cellular cytotoxicity, phagocytosis, and direct B-cell killing better than rituximab. Our aim was to determine the activity and safety of lenalidomide plus obinutuzumab in previously treated patients with relapsed or refractory follicular lymphoma.

METHODS

In this multicentre, single-arm, phase 2 study, patients were enrolled from 24 Lymphoma Academic Research Organisation centres in France. Eligible patients (age ≥18 years) had histologically confirmed CD20-positive relapsed or refractory follicular lymphoma of WHO grade 1, 2, or 3a; an ECOG performance status of 0-2; and received at least one previous rituximab-containing therapy. Patients received oral lenalidomide (20 mg) plus intravenously infused obinutuzumab as induction therapy (1000 mg; six 28-day cycles), 1-year maintenance with lenalidomide (10 mg; 12 28-day cycles; days 2-22) plus obinutuzumab (1000 mg; alternate cycles), and 1-year maintenance with obinutuzumab (1000 mg; six 56-day cycles; day 1). The primary endpoint was the proportion of patients who achieved an overall response at induction end as per investigator assessment using the 1999 international working group criteria. The secondary endpoints were event-free survival, progression-free survival, overall survival, and safety. Analyses were per-protocol; the efficacy population included all patients who received at least one dose of both obinutuzumab and lenalidomide, and the safety population included all patients who received one dose of either investigational drug. The study is registered with ClinicalTrials.gov, number NCT01582776, and is ongoing but closed to accrual.

FINDINGS

Between June 11, 2014, and Dec 18, 2015, 89 patients were recruited and 86 patients were evaluable for efficacy and 88 for safety. Median follow-up was 2·6 years (IQR 2·2-2·8). 68 (79%) of 86 evaluable patients (95% CI 69-87) achieved an overall response at induction end, meeting the prespecified primary endpoint. At 2 years, event-free survival was 62% (95% CI 51-72), progression-free survival 65% (95% CI 54-74), duration of response 70% (95% CI 57-79), and overall survival 87% (95% CI 78-93). Complete response was achieved by 33 (38%, 95% CI 28-50) of 86 patients at induction end, and the proportion of patients achieving a best overall response was 70 (81%, 95% CI 72-89) and 72 (84%, 74-91) of 86 patients during induction and treatment, respectively. The most common adverse events were asthenia (n=54, 61%), neutropenia (n=38, 43%), bronchitis (n=36, 41%), diarrhoea (n=35, 40%), and muscle spasms (n=34, 39%). Neutropenia was the most common toxicity of grade 3 or more; four (5%) patients had febrile neutropenia. 57 serious adverse events were reported in 30 (34%) of 88 patients. The most common serious adverse events were basal cell carcinoma (n=5, 6%), febrile neutropenia (n=4, 5%), and infusion-related reaction (n=3, 3%). One patient died due to treatment-related febrile neutropenia.

INTERPRETATION

Our data shows that lenalidomide plus obinutuzumab is active in previously treated patients with relapsed or refractory follicular lymphoma, including those with early relapse, and has a manageable safety profile. Randomised trials of new immunomodulatory regimens, such as GALEN or using GALEN as a backbone, versus lenalidomide plus rituximab, are warranted.

FUNDING

Lymphoma Academic Research Organisation, and Celgene and Roche.

Dual-tracer PET/CT scan after injection of combined [18 F]NaF and [18 F]FDG outperforms MRI in the detection of myeloma lesions

The detection rates of whole-body combined [¹⁸ F]NaF/[¹⁸ F]FDG positron emission tomography combined with computed tomography (PET/CT), CT alone, whole-body magnetic resonance imaging (WB-MRI), and X-ray were prospectively studied in patients with treatment-requiring plasma cell disorders The detection rates of imaging techniques were compared, and focal lesions were classified according to their anatomic location. Twenty-six out of 30 initially included patients were assessable. The number of focal lesions detected in newly diagnosed patients (n = 13) and in relapsed patients (n = 13) were 296 and 234, respectively. The detection rate of PET/CT was significantly higher than those of WB-MRI (P < 0.05) and CT (P < 0.0001) both in patients with newly diagnosed and in those with relapsed multiple myeloma (MM). The X-ray detection rate was significantly lower than those of all other techniques, while CT detected more lesions compared with WB-MRI at diagnosis (P = 0.025). With regard to the infiltration patters, relapsed patients presented more diffuse patterns, and more focal lesions located in the limbs compared with newly diagnosed patients. In conclusion, the detection rate of [¹⁸ F]NaF/[¹⁸ F]FDG PET/CT was significantly higher than those of CT, MRI, and X-ray, while the detection rate of X-rays was significantly lower than those of all other imaging techniques except for focal lesions located in the skull.

Single gold bipyramids on a silanized substrate as robust plasmonic sensors for liquid environments

Sensitive, robust and stable sensors are required to bring biosensing techniques from the forefront of research to clinical and commercial settings. To this end, we report on the development of new robust plasmonic sensors consisting of gold nano-bipyramids (BPs) grafted to a glass substrate via silanization, associated with a novel setup based on Spatial Modulation Spectroscopy allowing the measurement of the optical response of individual nano-objects in a liquid environment. We thereby show that changes in the refractive index of the medium around individual silanized BPs can be detected by measuring their plasmonic shift with sensitivities comparable to values reported elsewhere and in good agreement with theoretical calculations. The optical response is furthermore shown to be stable and robust allowing for repeated measurements in different media and storage over many months. This work opens up new perspectives in the field of plasmonic bio-sensing as our setup is readily adaptable to dynamic liquid measurements and a wide range of applications such as the detection of clinically important analytes or pollutants in water.

Abstract 4921: Population pharmacokinetic modeling of ibrutinib administered in patients with relapsed or refractory B cell malignancies eligible for autologous stem cell transplantation

Background: Ibrutinib is a first-in-class selective, irreversible small molecule inhibitor of Bruton's tyrosine kinase (BTK). The present study's aim is to assess the feasibility and safety and pharmacokinetics (PK) of escalating doses of ibrutinib combined with rituximab (R), dexamethasone (D), ara-C (HA) and one of two platinum compounds (cisplatinum (P) or oxaliplatinum (Ox)) in patients with relapsed or refractory lymphoma. As part of this, Population PK (POPPK) modeling, PK parameters, and inter-individual and inter-occasion variabilities of oral ibrutinib in the presence of R-DHA(P/Ox) were assessed during the dose escalation part of this clinical trial.

Materials and methods: Dataset was obtained from an open label, multicenter, dose escalation, phase Ib study of ibrutinib in combination with R-DHA (P/Ox) in patients with B-cell malignancies. Patients received three doses (280, 420, 560 mg) of oral ibrutinib once a day D5 to D18. Blood samples were collected during cycles 1 and 2 on D5, Just before ibrutinib intake (T0) and at 1, 2 and 4 hours after ibrutinib intake and on D15 at T0 and 1 hour after ibrutinib intake. Ibrutinib plasma concentrations were measured using validated ultra-performance liquid chromatography with tandem mass spectrometry detection with a concentration range 1-400ng/mL. Analyses and POPPK modeling were performed with the nonlinear mixed effect modeling software program Monolix version 4.3.2. The following parameters were calculated Lagtime (Tlag), absorption constant (Ka); apparent distribution volumes (V1/F, V2); apparent clearances (CL/F, Q).

Results: 24 pts (18 male, 6 female), have validated PK data with 184 plasma concentrations. A 2-compartment model with linear elimination and lag time adequately described the total ibrutinib time-concentration curve. The main PK parameters (RSE%) estimated for ibrutinib were Tlag=0.6 (15), Ka=3.36 (36) h-1, CL/F= 699 (12) L/h, Q=182 (1) L/h, V1/F=5,060 (15) L, and V2=32,100 (49) L. The main covariate effect on ibrutinib CL was related to body weight (BW). The inter-individual and variabilities could be well estimated for CL and V1 and inter-occasion variabilities were well estimated for Tlag and V1.

Conclusions: The POPPK modeling satisfactorily described the plasma ibrutinib time-concentration curves in patients. Our data revealed the effect of BW on ibrutinib PK parameters. A large volume of the deep compartment suggest that ibrutinib has large tissue diffusion. The clinical data describes the toxicity and efficacy. This is an analysis of correlation between the PK and the clinical outcomes.

Citation Format: Keyvan Rezai, Olivier Madar, Christophe Bonnet, Jean Dupuis, Hervé Tilly, Thierry Lamy de la Chapelle, Steven Le Gouill, Ombeline Verite, Julie Assemat, Fanny Bret, Sophie Weill, François Lokiec, Gilles Salles. Population pharmacokinetic modeling of ibrutinib administered in patients with relapsed or refractory B cell malignancies eligible for autologous stem cell transplantation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4921.

Acoustic Mode Hybridization in a Single Dimer of Gold Nanoparticles

The acoustic vibrations of single monomers and dimers of gold nanoparticles were investigated by measuring for the first time their ultralow-frequency micro-Raman scattering. This experiment provides access not only to the frequency of the detected vibrational modes but also to their damping rate, which is obscured by inhomogeneous effects in measurements on ensembles of nano-objects. This allows a detailed analysis of the mechanical coupling occurring between two close nanoparticles (mediated by the polymer surrounding them) in the dimer case. Such coupling induces the hybridization of the vibrational modes of each nanoparticle, leading to the appearance in the Raman spectra of two ultralow-frequency modes corresponding to the out-of-phase longitudinal and transverse (with respect to the dimer axis) quasi-translations of the nanoparticles. Additionally, it is also shown to shift the frequency of the quadrupolar modes of the nanoparticles. Experimental results are interpreted using finite-element simulations, which enable the unambiguous identification of the detected modes and despite the simplifications made lead to a reasonable reproduction of their measured frequencies and quality factors. The demonstrated feasibility of low-frequency Raman scattering experiments on single nano-objects opens up new possibilities to improve the understanding of nanoscale vibrations with this technique being complementary with single nano-object time-resolved spectroscopy as it gives access to different vibrational modes.