1. Department of Oncology, Hebei General Hospital, Shijiazhuang, Hebei 050051, P.R. China
2. Department of Thoracic Surgery, Hebei General Hospital, Shijiazhuang, Hebei 050051, P.R. China
3. Second Department of Surgery, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
4. Fifth Department of Oncology, The First Hospital of Shijiazhuang, Shijiazhuang, Hebei 050011, P.R. China