Fig. 1From: Postoperative survival effect of the number of examined lymph nodes on esophageal squamous cell carcinoma with pathological stage T1–3N0M0The diagram of the patient screening process in the SYSUCC and SEER database (SYSUCC Sun Yat-sen University Cancer Center, SEER Surveillance Epidemiology and End Results, AJCC American Joint Committee on Cancer Staging Manual)Back to article page