Immunotherapy combined with chemotherapy without locoregional radiotherapy in de novo metastatic nasopharyngeal carcinoma: two case reports and a literature review - Gao, Yingna; Shi, Xiaoqiong; He, Jianqiao; Yao, Hui; Yu, Guoning; Zhao, Lin; Ma, Yi; Zheng, Hongliang; Zhu, Minhui; Zhang, Caiyun (Frontiers in Immunology, 2025)