All eligible patients from 3 hospitals will be equally randomized between the 2 following treatment groups:~Standard treatment group: Camrelizumab 200mg IV every 2 weeks. Experimental group: Stereotactic body radiotherapy 27Gy/3F and Camrelizumab 200mg IV every 2 weeks.
Camrelizumab is an antibody targeting programmed death receptor 1 (PD-1) and its ligand programmed death-ligand 1 (PD- L1) that is designed to boost the immune system. It does this by allowing immune cells to fight the cancer. Camrelizumab has been approved by China's National Medical Products Administration (NMPA) for the treatment of esophageal cancer, liver cancer and lung cancer. It is currently under study for the treatment of head and neck squamous cell cancer.