Table 2 Univariate analysis for the influence of different cutoffs of tumor size on CSS in perihilar cholangiocarcinoma

< 18

71

47.9

23.2

7.407

0.006

41

16

1.705

≥18

292

24.7

25

< 19

85

42.6

17.7

9.443

0.002

40

16

1.737

≥19

278

24.9

24

< 20

88

43.5

19.1

11.37

0.001

41

17

1.83

≥20

275

24.4

24

< 21

122

37.9

13.4

9.716

0.002

38

15

1.617

≥21

241

24.5

23

< 22

130

37.3

13.1

9.474

0.002

38

15

1.589

≥22

233

24.2

23

< 23

143

36.4

12.5

10.119

0.001

35

12

1.59

≥23

220

23.9

23

< 24

152

36.9

13.8

11.094

0.001

35

13

1.614

≥24

211

23.1

22

< 25

162

36.2

13.1

9.885

0.002

35

12

1.561

≥25

201

23.1

23

< 26

187

33.9

10

7.067

0.008

33

10

1.477

≥26

176

23.9

23

< 27

189

35.2

12.8

9.061

0.003

35

12

1.518

≥27

174

22.4

23

< 28

195

34.9

12.5

9.97

0.002

35

13

1.548

≥28

168

22.4

22

< 29

200

35.3

13.4

9.969

0.002

33

11

1.547

≥29

163

21.9

22

< 30

202

34.9

12.7

8.494

0.004

33

11

1.497

≥30

161

22.2

22

< 31

236

33.6

12.9

8.859

0.003

32

10

1.52

≥31

127

20.7

22

< 32

240

33.9

14.3

9.037

0.003

32

10

1.529

≥32

123

19.6

22

< 33

246

35.1

18.5

13.726

0

32

14

1.687

≥33

117

16.6

18

< 34

248

35.8

20.4

16.741

0

32

14

1.78

≥34

115

15.4

18

< 35

248

35.8

20.4

16.741

0

32

14

1.78

≥35

115

15.4

18

< 36

264

34.2

19

13.681

0

32

14

1.715

≥36

99

15.2

18

< 37

213

35.1

13.6

7.73

0.005

32

9

1.469

≥37

150

21.5

22.5

< 38

214

34.9

13.2

7.263

0.007

24.8

2.3

1.452

≥38

149

21.7

22.5

< 39

217

34.4

12.3

5.362

0.021

24.6

1.7

1.379

≥39

146

22.1

22.9

< 40

277

33

16.4

7.667

0.006

24.9

4.4

1.527

≥40

86

16.6

20.5