Table 1 Characteristics of included studies.

Read¹⁶

2006

Australia

51 (30/21)

64 (40–79)^a

chemotherapy

Median: 29.8 months

IV

Ishizuka¹⁷

2007

Japan

315 (186/129)

<70: 162; ≥70: 153

surgery

11 days-13.7 months

0-IV

Xiao²²

2013

China

223 (148/75)

<65: 181; ≥65: 42

Surgery

43 (6–84) months

I-IV

Kobayashi²⁴

2014

Japan

106 (77/29)

<70: 66; ≥70: 40

Surgery

Median: 38 m

IV

Nozoe²⁵

2014

Japan

272 (160/112)

70.4 (24–90)^a

Surgery

NR

I–IV

Lin²⁶

2015

China

99 (35/64)

62.63 ± 10.86^b

Surgery

Median: 60 months

II

Shibutani²⁷

2015

Japan

254 (139/115)

60 (26–86)^a

surgery

NR

II、III

Ishizuka²⁸

2016

Japan

627 (400/227)

67.75 ± 11.69^b

Surgery

NR

0–IV

Eren²⁹

2016

Turkey

115 (64/51)

66.1 ± 12.77^b

Surgery

20 (7–41) months

I–IV

Kishiki³²

2013

Japan

79 (42/37)

≤70: 43; >70: 36

Surgery

32 (1–66) months

IV

Son¹⁵

2013

Korea

624 (368/256)

<60: 295; ≥60: 329

Surgery

42 (1–66) months

I–III

Adachi³⁵

2015

Japan

65 (37/28)

64 (17–83)^a

surgery

NR

I–IV

Ghanim³⁶

2015

Austria

52 (31/21)

62.7 ± 11.4^b

surgery

NR

IV

Song³⁷

2015

Koea

177 (83/94)

52 (25–81)^a

Korean treatmen

3.1 (0.1–33.3) months

IV

Toiyama³⁰

2011

Japan

219 (136/83)

66 (58–73)^a

surgery

52.7 (56.9 63.8) months

II, III

Park³⁸

2016

UK

1000 (548/452)

<65: 330; 65–74: 347; >75: 323

surgery

56 (10–206) months

0–III

Choi²³

2014

Korea

105 (63/42)

63 (32–86)^a

Surgery

44 (2–81) months

I–IV

Leitch¹⁴

2007

UK

233 (129/104)

<65: 34; 65–74: 27; >75: 23

Surgery + chemotherapy

12 (6–73) months

I–IV

Manabu³¹

2012

Japan

42 (26/16)

<70: 12; ≥70: 30

chemotherapy

Median: 424 days

IV

Inoue³³

2013

Japan

245 (146/99)

64 (29–85)^a

chemotherapy

NR

IV

Nakagawa³⁴

2014

Japan

343 (219/124)

62.83 ± 3.85

surgery

NR

IV

Kobayashi¹⁸

2010

Japan

63 (44/19)

<70: 41; ≥70: 22

surgery

38 (30.5–45.6) months

I–IV

Furukawa¹⁹

2012

Japan

40 (30/10)

66.1 ± 9.7^b

chemotherapy

NR

IV

Sugimoto²⁰

2012

Japan

366 (209/157)

≤70: 240; >70: 126

surgery

Median: 70.8 months

II, III

Madea²¹

2013

Japan

94 (51/43)

<70: 62; ≥70: 32

surgery

Median: 21 months

IV

First Author

Survival analysis

Cut-off value

Lymphatic invasion (+/−)

Nevous invasion (+/−)

CEA (ng/ml)

Read¹⁶

OS

1

NR

NR

NR

Ishizuka¹⁷

OS

1

NR

NR

<6: 185; ≥6: 120

Xiao²²

OS

1

NR

NR

<5: 127; ≥5: 96

Kobayashi²⁴

OS

1

75/31

96/10

<30: 75; ≥30: 56

Nozoe²⁵

OS

2

112/160

65/207

NR

Lin²⁶

OS

2

NR

27/72

≤10: 73; >10: 26

Shibutani²⁷

OS

1

184/47

68/170

≤5: 154; >5: 44

Ishizuka²⁸

OS

2

129/498

131/496

≤8.7: 433; >8.7: 194

Eren²⁹

OS

2

68/47

NR

<5: 97; ≥5: 18

Kishiki³²

OS

2

NR

NR

<6: 19; ≥6: 60

Son¹⁵

OS

2

NR

NR

<5: 450; ≥5: 172

Adachi³⁵

OS

2

NR

NR

<10: 25; ≥10: 40

Ghanim³⁶

OS

1

NR

NR

NR

Song³⁷

OS

1

NR

NR

≤5: 31; >5: 140

Toiyama³⁰

OS、CSS

1

191/28

96/123

≤6: 134; >6: 85

Park³⁸

OS、CSS

1

NR

507/493

NR

Choi²³

CSS

2

NR

NR

<5: 63; ≥5: 41

Leitch¹⁴

CSS

1

NR

NR

NR

Manabu³¹

CSS

2

NR

NR

NR

Inoue³³

CSS

2

NR

NR

NR

Nakagawa³⁴

CSS

1

NR

NR

124.4 ± 116.6

Kobayashi¹⁸

CSS

1

49/14

53/10

<30: 43; ≥30: 18

Furukawa¹⁹

CSS

2

NR

NR

<100: 22; ≥100: 18

Sugimoto²⁰

CSS

2

362/4

343/23

≤3: 154; >3: 212

Madea²¹

CSS

2

NR

NR

NR