Corrigendum: Low Lymphocyte Count Is Associated With Radiotherapy Parameters and Affects the Outcomes of Esophageal Squamous Cell Carcinoma Patients - Wang, Xin; Zhao, Zongxing; Wang, Peiliang; Geng, Xiaotao; Zhu, Liqiong; Li, Minghuan (Frontiers in Oncology, 2021)