Table 2 Univariate analysis of predictors for TRG in the training and validation cohorts

No. of patients

33

38

33

42

Age (mean, y ± SD)

52 ± 12

56 ± 12

55 ± 13

55 ± 11

0.827

Gender

0.627

 Male

21 (64%)

26 (68%)

16 (49%)

18 (43%)

 Female

12 (36%)

12 (32%)

17 (51%)

24 (57%)

Pretreatment T stage

0.854

 T₂

0

0

2 (6%)

4 (9%)

 T₃

25 (76%)

27 (71%)

28 (85%)

34 (82%)

 T₄

8 (24%)

11 (29%

3 (9%)

4 (9%)

Pretreatment N stage

0.638

 N₀

5 (16%)

7 (18%)

10 (30%)

11 (26%)

 N₁

14 (42%)

16 (42%)

16 (49%)

18 (43%)

 N₂

14 (42%)

15 (40%)

7 (21%)

13 (31%)

Tumor differentiation

0.732

 Well/Moderately

19 (58%)

15 (40%)

24 (73%)

32 (76%)

 Poorly/Undifferentiated

14 (42%)

23 (60%)

9 (27%)

10 (24%)

Distance from the anal verge

0.924

 ≦5 cm

13 (39%)

22 (58%)

13 (39%)

17 (41%)

  > 5 cm

20 (61%)

16 (42%)

20 (61%)

25 (59%)

Tumor length

0.011

 ≦4 cm

19 (42%)

11 (71%)

19 (58%)

12 (29%)

  > 4 cm

14 (58%)

27 (29%)

14 (42%)

30 (64%)

Circumferential extent

0.163

 ≦50%

12 (36%)

5 (13%)

9 (27%)

18 (43%)

  > 50%

21 (64%)

33 (87%)

24 (73%)

24 (57%)

Pre-treatment CEA level

(mean, ng/ml; 95%CI)

29 (16–43)

25 (17–34)

15 (11–18)

14 (11–16)

0.548

Post- treatment CEA level (mean, ng/mL; 95%CI)

4 (1–7)

6 (4–9)

5 (4–7)

7 (4–9)

0.343

Normalization of post- treatment CEA Level

0.187

 Normal (< 5 ng/mL)

26 (79%)

21 (55%)

23 (70%)

23 (55%)

 Elevated (≧5 ng/mL)

7 (21%)

17 (45%)

10 (30%)

19 (45%)

CEA clearance pattern

0.016

 Exponential decrease (R²≧0.9)

19 (58%)

12 (32%)

21 (64%)

15 (36%)

 Non-exponential decrease (R² < 0.9)

14 (42%)

26 (68%)

12 (36%)

27 (64%)

Concurrent chemotherapy

NA

 Capecitabine

0

0

33 (44%)

42 (56%)

 Infusional fluorouracil

15 (45%)

24 (63%)

0

0

 mFOLFOX6

48 (55%)

14 (37%)

0

0