Corrigendum to "Extent of paranasal sinus involvement and its prognostic value in nasopharyngeal carcinoma: Proposed modification in the current UICC/AJCC staging system" [Radiother Oncol 160 (2021) 221–227]. (October 2021) - Wang, Xiao-Yi; Zhu, Si-Yu; Wu, Wei-Jie; Li, Hao-Jiang; Li, Jiao; Lin, Xiao-Feng; Li, Li; Liu, Li-Zhi