Table 1 Baseline characteristics and pathologic outcomes of rectal cancer patients in RS, LS and open surgery groups

Age (years, median ± SD)

62 ± 12.1

60 ± 11.1

64 ± 10.4

0.058

Gender

0.253

 male

192 (64%)

54 (61.4%)

20 (54.1%)

118 (67.4%)

 female

108(36%)

34 (38.6%)

17(45.9%)

57 (32.6%)

Tumor size

0.201

  > 5 cm

55 (18.3%)

11 (12.5%)

9 (24.3%)

35 (20%)

 ≦5 cm

245 (81.7%)

77 (87.5%)

28 (76.7%)

140 (80%)

 proximal

6.5 ± 3.3

8.8 ± 4.1

5.5 ± 4.1

0.038*

 distal

2.3 ± 1.5

2.5 ± 2.4

2.2 ± 1.9

0.679

Distal resection margin

0.794

  > 2 cm

182 (60.7%)

56 (63.6%)

22 (59.5%)

104 (59.4%)

 ≦2 cm

118 (39.3%)

32 (36.4%)

15 (40.5%)

71 (40.6%)

Number of retrieval LN (median ± SD)

9.0 ± 5.3

13.0 ± 6.6

14.0 ± 6.6

< 0.001*

Retrieval lymph nodes

0.417

 Adequate

274 (91.3%)

78 (88.6%)

33 (89.3%)

163 (93.1%)

 inadequate

26 (8.7%)

10 (11.4%)

4 (10.7%)

12 (6.9%)

Pre-operative CCRT

< 0.001*

 yes

156 (52%)

72 (81.8%)

15 (40.5%)

69 (39.4%)

 no

144 (48%)

16 (18.2%)

22 (59.5%)

106 (60.6%)

Histologic grade

0.158

 WD

35 (11.7%)

14 (15.9%)

2 (5.4%)

19 (10.9%)

 MD

251 (83.7%)

67 (76.1%)

34 (91.9%)

150 (85.7%)

 PD

14 (4.7%)

7 (8%)

1 (2.7%)

6 (3.4%)

LVI

0.006*

 yes

109 (36.3%)

21 (23.9%)

19 (51.4%)

69 (39.4%)

 no

191 (63.7%)

67 (76.1%)

18 (48.6%)

106 (60.6%)

PNI

0.058

 yes

70 (23.3%)

16 (18.2%)

14 (37.8%)

40 (22.9%)

 no

230 (76.7%)

72 (81.8%)

23 (62.2%)

135 (77.1%)

CRM (mm, median ± SD)

8.0 ± 6.4

5.0 ± 7.8

5.0 ± 7.2

0.118

CRM involvement

0.037*

 yes

30 (10%)

3 (3.4%)

6 (16.2%)

21 (12%)

 no

270 (90%)

85 (96.6%)

31 (83.8%)

154 (88%)

pStage (AJCC 7th edition)

0.014*

 pCR

50 (16.7%)

24 (27.3%)

5 (13.5%)?

21 (12%)

 I

82 (27.3%)

27 (30.7%)

9 (24.3%)

46 (26.3%)

 II

73 (24.3%)

17 (19.3%)

7 (18.9%)

49 (28%)

 III

95 (31.7%)

20 (22.7%)

16 (43.2%)

59 (33.7%)

Tumor depth

0.005*

  (y)pT0

53 (17.7%)

26 (29.5%)

5 (13.5%)

22 (12.6%)

  (y)pT1

31 (10.3%)

13 (14.8%)

2 (5.4%)

16 (9.1%)

  (y)pT2

71 (23.7%)

19 (21.6%)

11 (29.7%)

41 (23.4%)

  (y)pT3

145 (48.3%)

30 (34.1%)

19 (51.4%)

96 (54.9%)

Lymph node metastasis

0.041*

  (y)pN0

205 (68.3%)

68 (77.3%)

21 (56.8%)

116 (66.3%)

  (y)pN1

66 (22%)

18 (20.5%)

10 (27%)

38 (21.7%)

  (y)pN2

29 (9.7%)

2 (2.2%)

6 (16.2%)

21 (12%)

Tumor regression score after CCRT

0.784

 0

50 (32.1%)

24 (33.3%)

5 (33.3%)

21 (30.4%)

 1

61 (39.1%)

32 (44.4%)

5 (33.3%)

24 (34.8%)

 2

34 (21.8%)

12 (16.7%)

4 (26.7%)

18 (26.1%)

 3

11 (7.1%)

4 (5.6%)

1 (6.7%)

6 (8.7%)

Pathologic complete response after CCRT

0.928

 yes

50 (32.1%)

24 (33.3%)

5 (33.3%)

21 (30.4%)

 no

106 (67.9%)

48 (66.7%)

10 (66.7%)

48 (69.6%)

Post-operative distant metastasis

0.151

 yes

68 (22.7%)

19 (21.6%)

13 (35.1%)

36 (20.6%)

 no

232 (77.3%)

69 (78.4%)

24 (64.9%)

139 (79.4%)

Post-operative local recurrence

< 0.001*

 yes

22 (7.3%)

2 (2.3%)

8 (21.6%)

12 (6.9%)

 no

278 (92.7%)

86 (97.7%)

29 (78.4%)

163 (93.1%)