Table 1.

Characteristics of the studies include in the meta-analysis

Study	Year	Journal	Study design	Region	Study population, n	Operation time
Li et al[10]	2012	J Surg Oncol	Obser.	China	3FL: 136; 2FL: 227	2003-2010
Thakur et al[9]	2011	Indian J Cancer	Obser.	Nepal	3FL: 61; 2FL: 21	2003-2011
Shim et al[12]	2010	J Thorac Oncol	Obser.	South Korea	3FL: 57; 2FL: 34	1994-2007
Zhang et al[11]	2008	Zhonghua Zhongliu Zazhi	Obser.	China	3FL: 60; 2FL: 62	2001-2006
Igaki et al[13]	2004	Ann Surg	Obser.	Japan	3FL: 101; 2FL: 55	1988-1997
Noguchi et al[14]	2004	Dis Esophagus	Obser.	Japan	3FL: 68; 2FL: 78	1990-2001
Hagry et al[15]	2003	Eur J Cardiothorac Surg	Obser.	Belgium	3FL: 34; 2FL: 38	1975-2001
Gradauskas et al[16]	2002	Medicina (Kaunas)	Obser.	Lithuania	3FL: 23; 2FL: 19	1997-2002
Shiozaki et al[17]	2001	Dis Esophaguss	Obser.	Japan	3FL: 129; 2FL: 123	1985-1998
Tabira et al[18]	1999	J Cardiovasc Surg	Obser.	Japan	3FL: 66; 2FL: 86	1983-1996
Kawahara et al[19]	1998	J Surg Oncol	Obser.	Japan	3FL: 44; 2FL: 44	1974-1995
Nishihira et al[7]	1998	Am J Surg	RCT.	Japan	3FL: 32; 2FL: 30	1987-1994
Fujita et al[20]	1995	Ann Surg	Obser.	Japan	3FL: 63; 2FL: 65	1986-1991
Kakegawa et al[21]	1995	Gan To Kagaku Ryoho	Obser.	Japan	3FL: 124; 2FL: 107	1985-1994
Kato et al[22]	1995	Ann Chir Gynaecol	Obser.	Japan	3FL: 100; 2FL: 410	1962-1993
Akiyama et al[23]	1994	Ann Surg	Obser.	Japan	3FL: 324; 2FL: 393	1973-1993
Fujita et al[24]	1992	Kurume Med J	Obser.	Japan	3FL: 27; 2FL: 100	1982-1988
Isono et al[25]	1991	Oncology	Obser.	Japan	3FL: 1740; 2FL: 2671	1983-1989
Kato et al[8]	1991	Ann Thorac Surg	RCT	Japan	3FL: 77; 2FL: 73	1985-1989
Ando et al[26]	1989	Nihon Geka Gakkai Zasshi	Obser.	Japan	3FL: 22; 2FL: 56	1984-1988

Obser: Observational studies; 3FL: 3-field lymphadenectomy; 2FL: 2-field lymphadenectomy.