Jian Xu1, Jian Zhao1, Fang Liu1, Rui Zhang2. 1. Department of Colorectal Surgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital, Shenyang, China. 2. Department of Colorectal Surgery, Cancer Hospital of China Medical University, Liaoning Cancer Hospital, Shenyang, China - zzzrrr1234@sina.com.