1. Global cancer statistics, 2012;A Torre;CA Cancer J Clin,2015
2. 2. SEER 18 2006-2012, All Races, Both sexes by SEER Summary stage 2000.http://seer.cancer.gov/statfacts/html/esoph.html
3. 3. Stein HJ, Feith M, Bruecher BL, et al. Early oesophageal cancer: pattern of lymphatic spread and prognostic factors for long-term survival after surgical resection. Ann Surg 2005;242(4):566-73, discussion 573-5.
4. 4. Edge SB, Byrd DR. AJCC cancer staging manual. New York, NY: Springer 2010;7th edn:103-15.
5. Histopathologic findings predicting lymph node metastasis and prognosis of patients with superficial oesophageal carcinoma: analysis of 240 surgically resected tumours;Tajima;Cancer,2000