Table 2 The tumour characteristics in the included studies

Valdimarsson

101 (63.13%)

274 (72.68%)

20 (12–30) mm

20 (14–35) mm

2 (1–4)

2 (1–4)

Kaibori

/

17 (40.48%)

/

/

1: 2: 3 (4: 20: 8)

1: 2: 3 (9: 11: 22)

Le Souder

/

/

2 (1–3) cm

3 (2–6) cm

4 (2–8)

3 (1–4)

Luo

51 (39.53%)

169 (61.23%)

 < 5 cm: ≥ 5 cm (76: 53)

 < 5 cm: ≥ 5 cm (153: 123)

1: > 1 (81: 48)

1: > 1 (97: 179)

Martin

22 (31.43%)

130 (81.25%)

3.7 (0.3–8.8) cm

4 (0.8–13.0) cm

3 (1–16)

3 (1–8)

Martin

/

/

 ≤ 5 cm: > 5 cm (103: 31)

 ≤ 5 cm: > 5 cm (65: 41)

1: > 1 (81: 53)

1: > 1 (42: 64)

Moug

/

/

/

/

/

/

She

4 (14.29%)

28 (31.82%)

3.25 (1–20) cm

3.25 (0.8–21) cm

2 (1–multiple)

2 (1–multiple)

Thelen

/

/

 ≤ 50 mm: > 50 mm (24: 16)

 ≤ 50 mm: > 50 mm (101: 78)

1–3: ≥ 4 (34: 6)

1–3: ≥ 4 (122: 57)

Tsilimigras

80 (25.48%)

130 (34.30%)

2.5 (1.5–4.1) cm

3.0 (1.9–4.8) cm

2 (1–3)

2 (1–4)

Turrini

/

/

/

/

 < 4: > 4 (42: 15)

 < 4: > 4 (27: 35)

Weber

/

/

 ≤ 5 cm: > 5 cm (25: 10)

 ≤ 5 cm: > 5 cm (38: 24)

1–3: ≥ 4 (29: 6)

1–3: ≥ 4 (39: 23)

Yan

/

/

3.8 ± 3.4 cm

5.9 ± 3.8 cm

4 ± 2

3 ± 2

Vassiliou

/

/

/

/

/

/

de Haas

8(30.77%)

24(92.31%)

38 ± 33 mm

41 ± 21 mm

1: 2–3: > 3

(15: 7: 4)

1: 2–3: > 3 (15: 7: 4)

Boudjema

24 (61.54%)

28 (60.87%)

40.8 ± 28.8 mm

37.2 ± 33.5 mm

2 (1–13)

2 (1–9)

Kye

26 (18.18%)

35 (53.85%)

2.8 ± 1.9 cm

2.7 ± 2.1 cm

1.6 ± 1.1

2.4 ± 2.0

Abbott

46 (76.67%)

52 (61.90%)

/

/

 ≤ 5: > 5 (55: 5)

 ≤ 5: > 5 (57: 27)

Capussotti

3 (9.68%)

38 (79.17%)

5.5 (2.5–20) cm

5 (0.6–14) cm

1: 2: 3: 4: ≥ 5 (15: 5: 3: 4: 4)

1: 2: 3: 4: ≥ 5 (13: 12: 7: 6: 10)

Chua

/

/

3.7 ± 3.4 cm

3.9 ± 2.8 cm

2.5 ± 2.6

3 ± 2.2

Wu

213(43.03%)

202(40.81%)

/

/

/

/

Thongkan

8(38.10%)

84(93.33%)

40.1 (7.0–160.0) mm

41.5 (8.0–165.0) mm

2.4 (1.0–11.0)

2.4 (1.0–10.0)

Karam

19(86.36%)

17(77.27%)

24 (16–41) mm

20 (10–39) mm

5 (3–6)

3 (2–6)

Pooled differences (95% CI)

0.33(0.19–0.56)

P < 0.001

–0.10 (− 0.23 to 0.03)

P = 0.123

0.17 (− 0.25 to 0.58)

P = 0.437

Valdimarsson

/

/

/

/

25 (15.63%)

152 (40.32%)

135 (84.37%)

222 (59.68%)

Kaibori

25 (78.13%)

22 (52.38%)

7 (21.88%)

20 (47.62%)

/

/

/

/

Le Souder

11 (42.31%)

13 (48.15%)

15 (57.69%)

14 (51.85%)

12 (46.15%)

12 (44.44%)

14 (53.85%)

15 (55.56%)

Luo

/

/

/

/

44 (34.11%)

133(48.19%)

85(65.89%)

143(51.81%)

Martin

/

/

/

/

/

/

/

/

Martin

/

/

/

/

/

/

/

/

Moug

/

/

/

/

/

/

/

/

She

/

/

8 (28.57%)

24 (27.27%)

12(42.86%)

54(61.36%)

16(57.14%)

34(38.64%)

Thelen

25 (62.50%)

91 (50.84%)

15 (37.50%)

88 (49.16%)

15 (37.50%)

142 (79.33%)

25 (62.50%)

37 (20.67%)

Tsilimigras

/

/

/

/

61(19.43%)

164(43.27%)

253(80.57%)

212(55.94%)

Turrini

43 (75.44%)

25 (40.32%)

14 (24.56%)

37 (59.68%)

/

/

/

/

Weber

27 (77.14%)

20 (32.26%)

8 (22.86%)

42 (67.74%)

11 (31.43%)

35 (56.45%)

24 (68.57%)

27 (43.55%)

Yan

23 (31.51%)

20 (66.67%)

50 (68.49%)

10 (33.33%)

/

/

/

/

Vassiliou

/

/

5 (20.00%)

17 (21.79%)

7 (28.00%)

23 (29.49%)

18 (72.00%)

55 (70.51%)

de Haas

19 (73.08%)

19 (73.08%)

7 (26.92%)

7 (26.92%)

/

/

/

/

Boudjema

23 (58.97%)

27 (58.70%)

16 (41.03%)

19 (41.30%)

/

/

/

/

Kye

/

/

/

/

/

/

/

/

Abbott

/

/

/

/

20 (33.33%)

63 (75.00%)

40 (66.67%)

21 (25.00%)

Capussotti

/

/

10 (32.26%)

18 (37.50%)

/

/

/

/

Chua

32 (50.00%)

11 (34.38%)

32 (50.00%)

21 (65.63%)

/

/

/

/

Wu

307 (62.02%)

294 (59.39%)

188 (37.98%)

201 (40.61%)

99 (20.00%)

106 (21.41%)

396 (80.00%)

389 (78.59%)

Thongkan

/

/

2 (9.52%)

19 (21.11%)

Karam

/

/

9(40.91%)

13(59.09%)

2(9.09%)

1(4.55%)

20 (90.91%)

21 (95.45%)

1.52 (0.90–2.58)

P = 0.117

0.69 (0.46–1.03)

P = 0.070

0.43 (0.29–0.64)

P < 0.001

2.34 (1.53–3.58)

P < 0.001