Oncologic outcomes, prognostic factor analysis and therapeutic algorithm evaluation of head and neck mucosal melanomas in France

International audienceBackground:Head and neck mucosal melanoma (HNMM) is aggressive and rare, with a poor prognosis because of its high metastatic potential. The two main subtypes are sinonasal (sinonasal mucosal melanoma [SNMM]) and oral cavity (oral cavity mucosal melanoma [OCMM]). Consensual therapeutic guidelines considering the primary tumour site and tumour-node-metastasis (TNM) stage are not well established.Material & methods:Patients with HNMM from the prospective national French Rare Head and Neck Cancer Expert Network database between 2000 and 2017 were included. Clinical characteristics, treatment modalities, outcomes and prognostic factors were analysed.Results:In total, 314 patients were included. The 5-year overall survival (OS) and progression-free survival (PFS) rates were 49.4% and 24.7%, respectively, in the surgery group; no long-term survivors were observed when surgery was not feasible. Moreover, even after surgery, a high recurrence rate was reported with a median PFS of 22 months. In multivariate analysis, Union for International Cancer Control (UICC) stage and tumour site correlated with PFS and OS. Postoperative radiotherapy (PORT) improved the PFS but not OS in patients with small (T3) SNMM and OCMM tumours. Nodal involvement was more frequent in patients with OCMM (p < 10-4), although, as in SNMM, it was not a significant prognostic predictor.Conclusion:Even early HNMM was associated with poor oncologic outcomes due to distant metastases despite surgical resection with clear margins. Lymph node metastases had no impact on the prognosis, suggesting treatment de-escalation in cervical node management. PORT might be useful for local control

Oncologic outcomes, prognostic factor analysis and therapeutic algorithm evaluation of head and neck mucosal melanomas in France

International audienceBackground:Head and neck mucosal melanoma (HNMM) is aggressive and rare, with a poor prognosis because of its high metastatic potential. The two main subtypes are sinonasal (sinonasal mucosal melanoma [SNMM]) and oral cavity (oral cavity mucosal melanoma [OCMM]). Consensual therapeutic guidelines considering the primary tumour site and tumour-node-metastasis (TNM) stage are not well established.Material & methods:Patients with HNMM from the prospective national French Rare Head and Neck Cancer Expert Network database between 2000 and 2017 were included. Clinical characteristics, treatment modalities, outcomes and prognostic factors were analysed.Results:In total, 314 patients were included. The 5-year overall survival (OS) and progression-free survival (PFS) rates were 49.4% and 24.7%, respectively, in the surgery group; no long-term survivors were observed when surgery was not feasible. Moreover, even after surgery, a high recurrence rate was reported with a median PFS of 22 months. In multivariate analysis, Union for International Cancer Control (UICC) stage and tumour site correlated with PFS and OS. Postoperative radiotherapy (PORT) improved the PFS but not OS in patients with small (T3) SNMM and OCMM tumours. Nodal involvement was more frequent in patients with OCMM (p < 10-4), although, as in SNMM, it was not a significant prognostic predictor.Conclusion:Even early HNMM was associated with poor oncologic outcomes due to distant metastases despite surgical resection with clear margins. Lymph node metastases had no impact on the prognosis, suggesting treatment de-escalation in cervical node management. PORT might be useful for local control

Observational Signatures of Particle Acceleration in Supernova Remnants

We evaluate the current status of supernova remnants as the sources of Galactic cosmic rays. We summarize observations of supernova remnants, covering the whole electromagnetic spectrum and describe what these obser- vations tell us about the acceleration processes by high Mach number shock fronts. We discuss the shock modification by cosmic rays, the shape and maximum energy of the cosmic-ray spectrum and the total energy budget of cosmic rays in and surrounding supernova remnants. Additionally, we discuss problems with supernova remnants as main sources of Galactic cosmic rays, as well as alternative sources.Comment: Accepted for publication by Space Science Reviews, 81 page

Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation

The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for γ astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of γ cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of γ absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z=2 and to constrain or detect γ halos up to intergalactic-magnetic-field strengths of at least 0.3 pG . Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from γ astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of γ cosmology

Prospects for γ\gamma-ray observations of the Perseus galaxy cluster with the Cherenkov Telescope Array

Galaxy clusters are expected to be dark matter (DM) reservoirs and storage rooms for the cosmic-ray protons (CRp) that accumulate along the cluster's formation history. Accordingly, they are excellent targets to search for signals of DM annihilation and decay at gamma-ray energies and are predicted to be sources of large-scale gamma-ray emission due to hadronic interactions in the intracluster medium. We estimate the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse gamma-ray emission from the Perseus galaxy cluster. We perform a detailed spatial and spectral modelling of the expected signal for the DM and the CRp components. For each, we compute the expected CTA sensitivity. The observing strategy of Perseus is also discussed. In the absence of a diffuse signal (non-detection), CTA should constrain the CRp to thermal energy ratio within the radius $R_{500}$ down to about $X_{500}10^{27}$s for DM masses above 1 TeV. These constraints will provide unprecedented sensitivity to the physics of both CRp acceleration and transport at cluster scale and to TeV DM particle models, especially in the decay scenario

Galactic transient sources with the Cherenkov Telescope Array

International audienceA wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low-mass and high-mass X-ray binaries containing compact objects (e.g., novae, microquasars, transitional millisecond pulsars, supergiant fast X-ray transients), isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array (CTA) and the prospects for studying them with Target of Opportunity observations. We show that CTA will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. We also discuss the multi-wavelength synergies with other instruments and large astronomical facilities

Prospects for γ\gamma-ray observations of the Perseus galaxy cluster with the Cherenkov Telescope Array

International audienceGalaxy clusters are expected to be dark matter (DM) reservoirs and storage rooms for the cosmic-ray protons (CRp) that accumulate along the cluster's formation history. Accordingly, they are excellent targets to search for signals of DM annihilation and decay at gamma-ray energies and are predicted to be sources of large-scale gamma-ray emission due to hadronic interactions in the intracluster medium. We estimate the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse gamma-ray emission from the Perseus galaxy cluster. We perform a detailed spatial and spectral modelling of the expected signal for the DM and the CRp components. For each, we compute the expected CTA sensitivity. The observing strategy of Perseus is also discussed. In the absence of a diffuse signal (non-detection), CTA should constrain the CRp to thermal energy ratio within the radius $R_{500}$ down to about $X_{500}10^{27}$s for DM masses above 1 TeV. These constraints will provide unprecedented sensitivity to the physics of both CRp acceleration and transport at cluster scale and to TeV DM particle models, especially in the decay scenario

Prospects for a survey of the Galactic plane with the Cherenkov Telescope Array

International audienceApproximately one hundred sources of very-high-energy (VHE) gamma rays are known in the Milky Way. A survey of the entire Galactic Plane in the energy range from a few tens of GeV to a few hundred TeV has been proposed as a Key Science Project for the upcoming Cherenkov Telescope Array Observatory (CTAO). This article presents the status of the studies towards the Galactic Plane Survey (GPS). We build and make publicly available a sky model that combines data from observations of known gamma-ray emitters with state-of-the-art physically-driven models of synthetic populations of the main classes of established Galactic VHE sources, as well as of interstellar emission from cosmic-ray interactions in the Milky Way. We also perform an optimisation of the observation strategy. We use the improved sky model and observation strategy to simulate GPS data that are analysed using the methods and software tools under development for real data. We show that the GPS has the potential to increase the number of known Galactic VHE emitters by almost a factor of five. This corresponds to the detection of more than two hundred pulsar wind nebulae and a few tens of supernova remnants at average integral fluxes one order of magnitude lower than in the existing sample above 1 TeV, therefore opening the possibility to perform unprecedented population studies. The GPS also has the potential to provide new VHE detections of binary systems and pulsars, and to identify any bright PeVatrons. Furthermore, the GPS will constitute a pathfinder for deeper follow-up observations of these source classes. Finally, we show that we can extract from GPS data an estimate of the contribution to diffuse emission from unresolved sources, and that there are good prospects of detecting interstellar emission and statistically distinguishing different scenarios. (Abridged

Dark Matter Line Searches with the Cherenkov Telescope Array

International audienceMonochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of selected dwarf spheroidal galaxies. We find that current limits and detection prospects for dark matter masses above 300 GeV will be significantly improved, by up to an order of magnitude in the multi-TeV range. This demonstrates that CTA will set a new standard for gamma-ray astronomy also in this respect, as the world's largest and most sensitive high-energy gamma-ray observatory, in particular due to its exquisite energy resolution at TeV energies and the adopted observational strategy focussing on regions with large dark matter densities. Throughout our analysis, we use up-to-date instrument response functions, and we thoroughly model the effect of instrumental systematic uncertainties in our statistical treatment. We further present results for other potential signatures with sharp spectral features, e.g.~box-shaped spectra, that would likewise very clearly point to a particle dark matter origin