S (Additional file [0](#MOESM0){ref-type="media"}: Table S0). ASA (*P* = 0.000), tumor site (*P* = 0.000), tumor size (*P* \< 0.000), TNM stage (*P* \< 0.000), lymphovascular invasion (*P* = 0.000), perineural invasion (*P* \< 0.000), and postoperative chemotherapy (*P* = 0.000) 