Table 3 Univariate analysis of predictors for tumor downstaging in the training and validation cohorts

No. of patients

20

51

26

49

Age (mean, y ± SD)

58 ± 10

52 ± 13

54 ± 10

55 ± 13

0.630

Gender

0.701

 Male

14 (70%)

33 (65%)

11 (42%)

23 (47%)

 Female

6 (30%)

18 (35%)

15 (58%)

26 (53%)

Pretreatment T stage

0.125

 T₂

0

0

2 (8%)

4 (8%)

 T₃

19 (95%)

33 (65%)

24 (92%)

38 (78%)

 T₄

1 (5%)

18 (35)

0

7 (14%)

Pretreatment N stage

0.858

 N₀

2 (10%)

10 (20%)

8 (31%)

13 (26%)

 N₁

12 (60%)

18 (35%)

12 (46%)

22 (45%)

 N₂

6 (30%))

23 (45%)

6 (23%)

14 (29%)

Tumor differentiation

0.818

 Well/Moderately

14 (70%)

20 (40%)

19 (73%)

37 (76%)

 Poorly/Undifferentiated

6 (30%)

31 (60%)

7 (27%)

12 (24%)

 Distance from the anal verge

0.235

 ≦5 cm

8 (40%)

27 (53%)

8 (31%)

22 (45%)

  > 5 cm

12 (60%)

24 (47)

18 (69%)

27 (55%)

Tumor length

0.267

 ≦4 cm

12 (60%)

18 (65%)

13 (50%)

18 (37%)

  > 4 cm

8 (40%)

33 (35%)

13 (50%)

31 (63%)

Circumferential extent

0.856

 ≦50%

8 (40%)

9 (18%)

9 (35%)

18 (37%)

  > 50%

12 (60%)

42 (82%)

17 (65%)

31 (63%)

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

23 (14–33)

28 (19–39)

17 (12–22)

13 (11–15)

0.066

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

5 (0.2–9)

6 (4–8)

6 (4–9)

6 (4–7)

0.712

Normalization of post- treatment CEA Level

0.600

 Normal (<  5 ng/mL)

16 (80%)

31 (61%)

17 (65%)

29 (60%)

 Elevated (≧ 5 ng/mL)

4 (20%)

20 (39%)

9 (35%)

20 (40%)

CEA clearance pattern

0.007

 Exponential decrease (R²≧0.9)

15 (75%)

16 (31%)

18 (69%)

18 (37%)

 Non-exponential decrease (R² < 0.9)

5 (25%)

35 (69%)

8 (31%)

31 (63%)

Concurrent chemotherapy

NA

 Capecitabine

0

0

26 (35%)

49 (65%)

 Infusional fluorouracil

10 (50%)

29 (57%)

0

0

 mFOLFOX6

10 (50%)

22 (43%)

0

0