Publications by authors named "N Chopin"

89 Publications

Development of a noninvasive HIFU treatment for breast adenocarcinomas using a toroidal transducer based on preliminary attenuation measurements.

Ultrasonics 2021 May 9;115:106459. Epub 2021 May 9.

LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003 Lyon, France. Electronic address:

Breast cancer is the most commonly diagnosed type of cancer among women. For the last fifteen years, treatments that are less invasive than lumpectomy, such as high-intensity focused ultrasound (HIFU) therapy, have been developed, with encouraging results. In this study, a toroidal HIFU transducer was used to create lesions of at least 2 cm in diameter within less than one minute of treatment. The toroidal HIFU transducer created two focal zones that led to large, fast and homogeneous ablations (10.5 cc/min). The experiments were conducted in 30 human samples of normal breast tissues recovered from mastectomies to measure acoustic attenuation (N = 30), and then, HIFU lesions were created (N = 15). Eight HIFU ablations were performed to evaluate the reproducibility of the lesions. HIFU lesions were created in 45 s with a toroidal HIFU transducer working at 2.5 MHz. The longest and shortest axes of the HIFU lesions were 21.7 ± 3.1 mm and 23.5 ± 3.3 mm respectively, corresponding to an average volume of 7.3 ± 1.4 cm. These HIFU lesions were performed at an average depth of 19.0 ± 1.5 mm, while the integrity of the skin was preserved. The HIFU-treated breast tissues had a higher level of attenuation (0.57 ± 0.11 Np.cm.MHz) when compared to the untreated tissues (0.21 ± 0.04 Np.cm.MHz). This study shows the feasibility of a fast and fully noninvasive treatment using a toroidal transducer for breast tumors measuring up to 15 mm in diameter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ultras.2021.106459DOI Listing
May 2021

Lack of prognostic impact of sentinel node micro-metastases in endocrine receptor-positive early breast cancer: results from a large multicenter cohort.

ESMO Open 2021 May 10;6(3):100151. Epub 2021 May 10.

Department of Medical Oncology, CRCM, Institut Paoli-Calmettes, Aix-Marseille Univ, CNRS, INSERM, Marseille, France.

Background: Prognostic impact of lymph node micro-metastases (pN1mi) has been discordantly reported in the literature. The need to clarify this point for decision-making regarding adjuvant therapy, particularly for patients with endocrine receptor (ER)-positive status and HER2-negative tumors, is further reinforced by the generalization of gene expression signatures using pN status in their recommendation algorithm.

Patients And Methods: We retrospectively analyzed 13 773 patients treated for ER-positive breast cancer in 13 French cancer centers from 1999 to 2014. Five categories of axillary lymph node (LN) status were defined: negative LN (pN0i-), isolated tumor cells [pN0(i+)], pN1mi, and pN1 divided into single (pN1 = 1) and multiple (pN1 > 1) macro-metastases (>2 mm). The effect of LN micro-metastases on outcomes was investigated both in the entire cohort of patients and in clinically relevant subgroups according to tumor subtypes. Propensity-score-based matching was used to balance differences in known prognostic variables associated with pN status.

Results: As determined by sentinel LN biopsy, 9427 patients were pN0 (68.4%), 546 pN0(i+) (4.0%), 1446 pN1mi (10.5%) and 2354 pN1 with macro-metastases (17.1%). With a median follow-up of 61.25 months, pN1 status, but not pN1mi, significantly impacted overall survival (OS), disease-free survival (DFS), metastasis-free survival (MFS), and breast-cancer-specific survival. In the subgroup of patients with known tumor subtype, pN1 = 1, as pN1 > 1, but not pN1mi, had a significant prognostic impact on OS. DFS and MFS were only impacted by pN1 > 1. Similar results were observed in the subgroup of patients with luminal A-like tumors (n = 7101). In the matched population analysis, pN1macro, but not pN1mi, had a statistically significant negative impact on MFS and OS.

Conclusion: LN micro-metastases have no detectable prognostic impact and should not be considered as a determining factor in indicating adjuvant chemotherapy. The evaluation of the risk of recurrence using second-generation signatures should be calculated considering micro-metastases as pN0.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.esmoop.2021.100151DOI Listing
May 2021

Molecular Characterization of Ovarian Yolk Sac Tumor (OYST).

Cancers (Basel) 2021 Jan 9;13(2). Epub 2021 Jan 9.

Centre Léon Berard (CLB), 69008 Lyon, France.

Most patients with malignant ovarian germ cell tumors (MOGTCs) have a very good prognosis and chemotherapy provides curative treatment; however, patients with yolk sac tumors (OYSTs) have a significantly worse prognosis. OYSTs are rare tumors and promising results are expected with the use of specific therapeutic strategies after the failure of platinum-based first-line and salvage regimens. We initiated a project in collaboration with EORTC SPECTA, to explore the molecular characteristics of OYSTs. The pilot project used retrospective samples from ten OYST relapsed and disease-free patients. Each patient had a molecular analysis performed with FoundationOne CDx describing the following variables according to the Foundation Medicine Incorporation (FMI): alteration type (SNV, deletion), actionable gene alteration, therapies approved in EU (for patient's tumor type and other tumor types), tumor mutational burden (TMB), and microsatellite instability (MSI) status. A total of 10 patients with OYST diagnosed between 2007 and 2017 had a molecular analysis. A molecular alteration was identified in four patients (40%). A subset of three patients (33.3% of all patients) harbored targetable oncogenic mutations in , , . Two patients at relapse harbored a targetable mutation. This retrospective study identifies clinically relevant molecular alterations for all relapsed patients with molecular analysis. Dedicated studies are needed to demonstrate the efficacy of specific therapeutic strategies after the failure of platinum-based first-line and salvage regimens and to explore the potential relationship of a molecular alteration and patient outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers13020220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7826864PMC
January 2021

Imprecise neural computations as a source of adaptive behaviour in volatile environments.

Nat Hum Behav 2021 01 9;5(1):99-112. Epub 2020 Nov 9.

Ecole Normale Supérieure, PSL Research University, Paris, France.

In everyday life, humans face environments that feature uncertain and volatile or changing situations. Efficient adaptive behaviour must take into account uncertainty and volatility. Previous models of adaptive behaviour involve inferences about volatility that rely on complex and often intractable computations. Because such computations are presumably implausible biologically, it is unclear how humans develop efficient adaptive behaviours in such environments. Here, we demonstrate a counterintuitive result: simple, low-level inferences confined to uncertainty can produce near-optimal adaptive behaviour, regardless of the environmental volatility, assuming imprecisions in computation that conform to the psychophysical Weber law. We further show empirically that this Weber-imprecision model explains human behaviour in volatile environments better than optimal adaptive models that rely on high-level inferences about volatility, even when considering biologically plausible approximations of such models, as well as non-inferential models like adaptive reinforcement learning.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41562-020-00971-zDOI Listing
January 2021

Impact of multidisciplinary tumour board in the management of ovarian carcinoma in the first-line setting. Exhaustive analysis from the Rhone-Alpes region.

Eur J Cancer Care (Engl) 2020 Nov 7;29(6):e13313. Epub 2020 Sep 7.

Oncology Department, Leon Berard Cancer Center, Lyon, France.

Objective: Epithelial ovarian cancer (EOC) is a poor prognosis disease partly linked to diagnosis at an advanced stage. The quality of care management is a factor that needs to be explored, more specifically optimal organisation of first-line treatment.

Methods: A retrospective study, dealing with all patients diagnosed within the Rhone-Alpes region with initial diagnosis EOC in 2012, was performed. The aim was to describe the impact of multidisciplinary tumour boards (MTB) in the organisation of care and the consequence on the patient's outcomes.

Results: 271 EOC were analysed. 206 patients had an advanced EOC. Median progression-free survival (PFS) is 17.8 months (CI95%, 14.6-21.2) for AOC. 157 patients (57.9%) had a front-line surgery versus 114 patients (42.1%) interval debulking surgery. PFS for AOC patients with no residual disease is 24.3 months compared with 15.3 months for patients with residual disease (p = .01). No macroscopic residual disease is more frequent in the patients discussed before surgery in MTB compared with patients not submitted before surgery (73% vs. 56.2%, p < .001).

Conclusion: These results highlight the heterogeneity of medical practices in terms of front-line surgery versus interval surgery, in the administration of neoadjuvant chemotherapy and in the setting of MTB discussion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ecc.13313DOI Listing
November 2020