Detection of immune-related adverse events by medical imaging in patients treated with anti-programmed cell death 1

Background: Programmed death receptor-1 blocking antibodies (anti-PD1) are a new standard of care in many cancer types. Patients benefit from improved survival but have the risk of immune-related adverse events (irAE). We evaluated if medical imaging procedures, used for anti-tumour response assessment, can detect irAEs. Materials and methods: All consecutive patients treated with anti-PD1 and with a medical imaging acquisition performed within 2 weeks with irAEs >= 2 were retrospectively included. Data were gathered from June 2014 to February 2017, and a central review was performed. The primary and secondary end-points were i) to evaluate the overall detection rate of irAEs by medical imaging and ii) to provide a comprehensive radiological description of irAEs. Results: Fifty-three patients (31 women, 22 men; average age: 61 years) were included. The primary tumour was melanoma (n=32), lung cancer (n=18) and other (n=3). Patients were treated with nivolumab (n=27) or pembrolizumab (n=26). Of 74 medical imaging procedures analysed (ratio=1.4 medical imaging per patient), 55 irAE were detected. The detection rate was overall: 74% (95 confidence interval: 63-84%), positron emission tomography with 18F-fludeoxyglucose integrated with computed tomography (18F-FDG PET/CT): 83% (n=10/12), magnetic resonance imaging: 83% (n=5/6), computed tomography scan: 79% (n=19/24), ultrasonography: 70% (n=19/27), standard X-rays: 40% (n=2/5), lung/mediastinum: 100% (n=7/7), enterocolitis: 100% (n=8/8), hypophysitis: 100% (n=3/3), thyroiditis: 75% (n=15/20), hepatitis: 67% (n=2/3), arthralgia or arthritis: 40% (n=2/5) and pancreas: 28% (n=2/7). Conclusion: Medical imaging detected 74% of irAE in patients treated with anti-PD1. Beyond response assessment, medical imaging can detect irAE and guide towards specific management. We described the most frequent sites and patterns of imaging findings. (C) 2018 Elsevier Ltd. All rights reserved.