Table 3. Study and population characteristics for studies of thoracic oesophageal carcinoma.

Study	Year	Country	Sample size	Male (%)	Mean age (years)	Mean lymph nodes	Squamous cell carcinoma (%)	Three-field dissection (%)	Upper (%)	Middle (%)	Lower (%)
Kawaguchi et al [22]	1973	Japan	65	82.2	60.0	20.0	100.0	100.0	0	69.2	30.8
Matsubara [23]	1992	Japan	110	UR (62.0)	UR (54.9)	UR (24.0)	UR (75.9)	100.0	16.4	62.7	20.9
Kakegawa et al [24]	1991	Japan	715	UR (78.6)	UR (54.4)	UR (14.2)	UR (96.9)	100.0	11.0	63.1	25.9
Fujita et al [25]	1994	Japan	70	88.6	58.5	81.8	100.0	100.0	14.3	52.9	32.8
Sayama et al [26]	1994	Japan	226	85.0	61.4	UR (55.5)	95.1	UR (100.0)	7.5	56.2	36.3
Shao et al [27]	1994	China	216	74.9	UR (62.8)	7.5	94.0	UR (7.4)	18.1	81.9	0
Su et al [28]	1994	China	175	UR (55.3)	UR (57.7)	16.3	UR (63.7)	21.7	21.7	64.6	13.7
Fu and Lian [29]	1996	China	1063	77.8	54.0	UR (26.7)	100.0	UR (99.1)	4.1	72.9	23.0
Bhansali et al [30]	1997	Japan	90	90.0	58.0	UR (59.6)	100.0	100.0	12.2	54.5	33.3
Nishimaki et al [31,32]	1997	Japan	154	92.9	60.5	77.2	94.8	100.0	6.5	51.3	42.2
Wang et al [33]	1997	China	130	86.2	57.5	UR (40.2)	90.8	UR (57.8)	47.7	52.3	0
She et al [34]	1998	China	230	76.1	56.4	25.0	100.0	100.0	23.5	63.5	13.0
Guo et al [35]	1999	China	616	63.0	UR (52.6)	UR (6.5)	100.0	100.0	10.3	72.4	17.3
Zheng et al [36]	1999	China	988	59.2	56.3	UR (3.4)	95.1	0	12.1	66.1	21.8
Wang et al [37]	2000	China	243	72.8	UR (61.0)	15.7	100.0	5.3	17.3	57.2	25.5
Xiang et al [38]	2001	China	100	79.0	56.1	30.1	91.0	100.0	14.3	75.5	10.2
Dresner et al [39]	2001	UK	104	86.5	62.9	22.0	0.0	0	0	0	100.0
Sato et al [40]	2002	Japan	155	82.0	63.9	41.7	100.0	51.6	12.3	64.5	23.2
An et al [41]	2003	China	217	66.8	56.0	18.4	100.0	100.0	18.9	54.4	26.7
He et al [42]	2003	China	150	78.7	UR (66.0)	UR (27.5)	100.0	4.7	14.0	58.7	27.3
Nakagawa et al [43]	2003	Japan	199	91.5	61.0	UR (52.0)	96.5	100.0	8.0	59.8	32.2
Stilidi et al [44]	2003	Russia	147	76.9	57.0	43.0	94.6	0	8.8	58.5	32.7
Li et al [45]	2004	China	104	63.5	56.8	UR (34.2)	100.0	100.0	100.0	0	0
Lerut et al [46]	2004	Belgium	174	85.6	59.3	59.2	44.8	100.0	6.5	30.4	63.1
Liu et al [47]	2005	China	472	77.8	57.0	21.7	94.3	100.0	11.2	71.4	17.4
Feith et al [43]	2006	Germany	621	63.0	61.0	UR (7.3)	0	0	0	0	100.0
Xu et al [49]	2007	China	308	63.0	57.5	UR (14.8)	100.0	100.0	10.4	73.4	16.2
Li et al [9]	2007	China	230	79.6	55.6	25.3	100.0	100.0	15.7	65.2	19.1
Sun et al [50]	2007	China	152	58.6	56.1	21.1	100.0	100.0	23.7	51.3	25.0
Fang et al [51]	2007	China	87	78.2	59.0	12.4	100.0	59.8	27.6	60.9	11.5
Xue et al [52]	2007	China	1412	51.0	58.0	UR (14.5)	98.2	0	14.3	68.8	16.9
Xiao et al [53]	2008	China	549	UR (71.0)	UR (58.8)	17.0	100.0	0	13.1	66.1	20.8
Liu et al [54]	2008	China	886	72.1	58.2	6.7	94.7	UR (38.6)	12.1	72.7	15.2
Wang et al [55]	2008	China	161	59.0	56.0	UR (6.6)	90.1	0	19.9	55.3	24.8
Meier et al [56]	2008	Germany	111	82.5	63.0	37.0	0	0	0	0	100.0
Chen et al [11]	2009	China	1850	73.0	55.0	26.0	100.0	100.0	15.6	74.7	9.7
Zhu et al [57]	2009	China	1690	53.6	57.3	UR (6.5)	98.0	0	14.0	65.0	21.0
Yang et al [58]	2010	China	160	70.6	UR (63.1)	UR (3.6)	100.0	0	18.8	55.0	26.2
Abula et al [59]	2010	China	215	74.4	61.0	21.9	100.0	100.0	9.6	57.7	32.7
Zhao et al [60]	2010	China	612	88.9	58.0	25.0	100.0	11.9	2.0	48.9	49.1
Huang et al [10]	2010	China	1077	78.1	UR (60.2)	19.7	100.0	UR (36.7)	5.0	63.2	31.8
Wu et al [61]	2010	China	262	81.7	55.2	22.0	94.3	100.0	36.6	48.1	15.3
Li et al [62]	2010	China Japan	763	68.9	59.0	7.7	93.4	11.1	15.4	61.5	23.1
Tachimori et al [3]	2011	Japan	127	90.6	62.7	UR (19.3)	100.0	100.0	17.3	52.8	29.9
Tachimori et al [3]	2011		229	86.9	62.8	UR (64.0)	100.0	100.0	14.4	46.3	39.3

UR, unreported (multiple imputation value in parentheses).