Sun R, Sundahl N, Hecht M, Putz F, Lancia A, Rouyar A, Milic M, Carré A, Battistella E, Alvarez Andres E, Niyoteka S, Romano E, Louvel G, Durand-Labrunie J, Bockel S, Bahleda R, Robert C, Boutros C, Vakalopoulou M, Paragios N, Frey B, Soria JC, Massard C, Ferté C, Fietkau R, Ost P, Gaipl U, and Deutsch E
Background: Combining radiotherapy (RT) with immuno-oncology (IO) therapy (IORT) may enhance IO-induced antitumor response. Quantitative imaging biomarkers can be used to provide prognosis, predict tumor response in a non-invasive fashion and improve patient selection for IORT. A biologically inspired CD8 T-cells-associated radiomics signature has been developed on previous cohorts. We evaluated here whether this CD8 radiomic signature is associated with lesion response, whether it may help to assess disease spatial heterogeneity for predicting outcomes of patients treated with IORT. We also evaluated differences between irradiated and non-irradiated lesions., Methods: Clinical data from patients with advanced solid tumors in six independent clinical studies of IORT were investigated. Immunotherapy consisted of 4 different drugs (antiprogrammed death-ligand 1 or anticytotoxic T-lymphocyte-associated protein 4 in monotherapy). Most patients received stereotactic RT to one lesion. Irradiated and non-irradiated lesions were delineated from baseline and the first evaluation CT scans. Radiomic features were extracted from contrast-enhanced CT images and the CD8 radiomics signature was applied. A responding lesion was defined by a decrease in lesion size of at least 30%. Dispersion metrices of the radiomics signature were estimated to evaluate the impact of tumor heterogeneity in patient's response., Results: A total of 94 patients involving multiple lesions (100 irradiated and 189 non-irradiated lesions) were considered for a statistical interpretation. Lesions with high CD8 radiomics score at baseline were associated with significantly higher tumor response (area under the receiving operating characteristic curve (AUC)=0.63, p=0.0020). Entropy of the radiomics scores distribution on all lesions was shown to be associated with progression-free survival (HR=1.67, p=0.040), out-of-field abscopal response (AUC=0.70, p=0.014) and overall survival (HR=2.08, p=0.023), which remained significant in a multivariate analysis including clinical and biological variables., Conclusions: These results enhance the predictive value of the biologically inspired CD8 radiomics score and suggests that tumor heterogeneity should be systematically considered in patients treated with IORT. This CD8 radiomics signature may help select patients who are most likely to benefit from IORT., Competing Interests: Competing interests: RS received travel and accommodation expenses from AstraZeneca. NS reports travel grants from Merck Sharpe & Dohme, Astellas, Bayer and Bristol-Myers Squibb. MH declares consulting fees, research grants and travel expenses from Merck Serono, MSD, Novartis, BMS and Teva. PO reports research grants from Merck Sharpe & Dohme, Astellas and Janssen; travel grants from Ipsen and Ferring Pharmaceuticals and honorarium from Ferring and Bayer. CR received research grants from Therapanacea and Elekta. CF is a full-time employee of AstraZeneca since September 2017. NP reports grants from GE, Biogen and consulting fees from AstraZeneca and Ipsen. J-CS reports consultancy fees from AstraZeneca, Astex, Clovis, GSK, GamaMabs, Lilly, MSD, Mission Therapeutics, Merus, Pfizer, PharmaMar, Pierre Fabre, Roche-Genentech, Sanofi, Servier, Symphogen, Takeda. J-CS has been Full time employee for AstraZeneca (September 2017–December 2019) and is a shareholder of AstraZeneca, Gritstone. CF received travel, accommodations, expenses from Amgen; Genentech; GlaxoSmithKline; MedImmune. CM is an advisory board member, speaker, investigator at Amgen, Astellas, AstraZeneca, Bayer, Celgene, Genentech, Ipsen, Janssen, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, Orion. USG received support for presentation activities for Dr Sennewald Medizintechnik GmbH, has received support for investigator initiated clinical studies (IITs) from MSD and AstraZeneca and contributed at Advisory Boards Meetings of AstraZeneca and Bristol-Myers Squibb. RF received grants/research support from MSD; AstraZeneca; Merck (Germany/Darmstadt); Novocure; honoraria/consultation fees: MSD; AstraZeneca; Merck (Germany/Darmstadt); Novocure; Fresenius and reports participation in a company sponsered speakers bureau: AstraZeneca; MSD; Merck (Germany/Darmstadt); Sennewald; Novocure; Brainlab; Roche. ED has declared consulting fees and support from Roche, BMS, Boehringer, AstraZeneca, Lilly Amgen and Merck-Serono., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)