Several models have been proposed to estimate the dose delivered to circulating immune cells. Before the era of immunotherapy (IO), several studies highlighted the detrimental impact of lymphopenia on patients treated by CCRT for unresectable LA-NSCLC ( 5– 8). One of the immunosuppressive effects of radiotherapy is the direct depletion of circulating lymphocytes or progenitors in lymphoid organs ( 3– 5). However, the optimal radiation therapy regimen in the context of immunotherapy remains to be determined.

The most important improvement in patients with unresectable stage III non-small cell lung cancer (NSCLC) was recently obtained by the addition of consolidation immunotherapy (durvalumab) to concurrent chemoradiation (CCRT), which now constitutes the standard of care ( 1, 2). The optimal sparing of immune structures might help in achieving better synergy between radiotherapy and immunotherapy in this indication. In multivariable analysis, NILN-R+ was the strongest factor associated with PFS (HR 3.15, p = 0.017).Ĭonclusion: The inclusion of at least one NITDLN station within the CTV was an independent factor for poorer PFS in the context of CCRT and durvalumab for LA-NSCLC.

In univariable analysis, NILN-R+ (hazard ratio (HR) 2.60, p = 0.028), estimated dose of radiation to immune cells (EDRIC) >6.3 Gy (HR 3.19, p = 0.049), and lymphopenia ≤ 500/mm 3 at IO initiation (HR 2.69, p = 0.021) were correlated with poorer PFS lymphopenia ≤ 500/mm 3 was also associated with poorer OS (HR 3.46, p = 0.024). Results: Fifty patients were included with a median follow-up of 23.2 months (95% CI 18.3–35.2). Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan–Meier method. Patients were divided into two groups according to the inclusion (NILN-R+) or not (NILN-R−) of at least one non-involved tumor-draining lymph node (NITDLN) in the clinical target volume (CTV). Material and methods: Clinicopathologic data, pre- and post-treatment blood counts, and dosimetric data were collected in patients treated with CCRT and durvalumab consolidation for LA-NSCLC. The aim of this study was to investigate the impact of radiation on different immune structures and immune cells in patients treated with CCRT followed by durvalumab. 7Institut National de la Santé et de la Recherche Médicale U1037, Centre de Recherche contre le Cancer de Toulouse, Toulouse, Franceīackground: The optimal modalities of radiotherapy when combining concurrent chemoradiation (CCRT) and immunotherapy (IO) for locally advanced non-small cell lung cancer (LA-NSCLC) remain to be determined.6Université de Toulouse III Paul Sabatier, Toulouse, France.5Department of Nuclear Medicine, Institut Claudius Regaud/Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France.4Department of Pulmonology, Centre Hospitalier Intercommunal des Vallées de l’Ariège (CHIVA), Saint-Jean-de-Verges, France.3Department of Thoracic Oncology, Centre Hospitalier Universitaire de Toulouse, Hôpital Larrey, Toulouse, France.2Department of Biostatistics, Institut Claudius Regaud/Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France.1Department of Radiation Oncology, Institut Claudius Regaud/Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France.Corentin Pasquier 1 Léonor Chaltiel 2 Carole Massabeau 1 Audrey Rabeau 3 Louisiane Lebas 4 Amélie Lusque 2 Jean-Sébastien Texier 5 Elizabeth Cohen-Jonathan Moyal 1,6,7 Julien Mazières 3,6 Jonathan Khalifa 1,6,7*

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