Retrospective Cohort Study
Copyright ©The Author(s) 2019.
World J Gastrointest Surg. May 27, 2019; 11(5): 247-260
Published online May 27, 2019. doi: 10.4240/wjgs.v11.i5.247
Table 1 Patient, surgery, and disease characteristics
VariableSGH cohort (n = 1267)
Age, median (range), yr77 (70-102)
Gender
Male658 (51.9)
Female609 (48.1)
Race
Chinese1148 (90.6)
Malay50 (4.0)
Indian30 (2.4)
Others39 (3.1)
ECOG status
0 (asymptomatic)751 (59.3)
1401 (31.6)
285 (6.7)
323 (1.8)
4 (bedbound)7 (0.2)
ASA score
1178 (14.0)
2857 (67.6)
3225 (17.8)
47 (0.6)
Tumor site
Colon790 (62.3)
Rectum477 (37.6)
Surgical approach
Open888 (70.1)
Laparoscopic379 (29.9)
Surgery
High Anterior resection505 (40.0)
Low Anterior resection163 (12.9)
Ultra-Low Anterior resection150 (11.8)
Right Hemicolectomy286 (22.6)
Abdominoperineal resection58 (4.6)
Others105 (8.3)
TMN stagea
1240 (18.9)
2416 (32.8)
3442 (34.9)
Tumor diameter, median (IQR), cm4.5 (3–6)
Number of lymph nodes harvested, median (IQR)15 (11–20)
Neoadjuvant therapy22 (1.8)
Adjuvant therapy219 (17.6)
Table 2 30-d post-operative complications n (%)
SGH cohort (n = 1267)
Overall 30-d complications297 (23.4)
Clavien-Dindo classification
I75 (5.9)
II140 (11.0)
III21 (1.7)
IV31 (2.4)
V (death)30 (2.4)
Type of complication
Cardiac/CVA97 (7.7)
Respiratory28 (2.2)
Urinary24 (1.9)
Wound/stoma55 (4.3)
Anastomotic leak16 (1.3)
Others77 (6.1)
Table 3 Unadjusted hazard ratios of individual predictors in association with 3-year survival duration obtained via univariate Royston-Parmar regression
PredictorsnHR (95%CI)P value
Gender12671.03 (0.81-1.31)0.807
Age12671.00 (0.98-1.03)0.826
Race
Chinese11481.00 (ref)
Malay501.14 (0.60-2.14)0.682
Indian301.43 (0.78-2.68)0.272
Others390.67 (0.25-1.82)0.433
Smoking status
Non-smoker10551.00 (ref)
Smoker2121.07 (0.78-1.47)0.692
Primary lesion site
Colon7901.00 (ref)
Rectum4771.40 (1.09-1.80)0.008
Tumor stage
Tis/T1971.00 (ref)
T21881.52 (0.31-7.41)0.605
T375210.8 (2.7-43.1)0.001
T4a9742.9 (10.5-173.5)< 0.001
T4b13337.9 (9.38-153.2)< 0.001
Tumor grade
Well differentiated1171.00 (ref)
Moderately differentiated10093.85 (1.82-8.15)< 0.001
Poorly differentiated or mucinous1418.59 (3.90-18.94)< 0.001
Past medical history
Diabetes Mellitus3311.07 (0.81-1.41)0.655
Hypertension4161.17 (0.91-1.51)0.217
End stage renal failure261.73 (0.54-5.53)0.354
Previous myocardial infarction470.95 (0.50-1.81)0.881
Previous PCI, cardiac surgery or angina1401.36 (0.88-2.09)0.161
Congestive heart failure411.18 (0.52-2.69)0.698
Peripheral vascular disease301.14 (0.52-2.53)0.744
Impaired sensorium, e.g., dementia142.77 (0.40-19.2)0.304
Chronic obstructive pulmonary disease610.44 (0.29-0.68)< 0.001
Previous stroke or TIA901.08 (0.66-1.76)0.758
Previous stroke with neurological deficits381.19 (0.53-2.69)0.675
Dependent functional status600.81 (0.43-1.54)0.529
ECOG
07511.00 (ref)
14040.98 (0.76-1.28)0.903
2 or more1161.13 (0.72-1.79)0.595
ASA
11781.00 (ref)
28570.75 (0.53-1.06)0.099
3 or more2320.78 (0.51-1.19)0.250
Laboratory parameters
Serum albumin (g/L)11190.94 (0.92-0.96)< 0.001
Carcinoembryonic antigen (µg/L)11961.01 (1.00-1.01)< 0.001
White blood cell count (× 109/L)12671.11 (1.06-1.15)< 0.001
Platelet count (× 103/L)12671.00 (1.00-1.00)< 0.001
Serum sodium (mmol/L)12470.95 (0.91-0.98)0.002
Serum creatinine (µmol/L)12651.00 (0.99-1.00)0.244
Serum potassium (mmol/L)12630.75 (0.56-0.99)0.049
Serum urea (mmol/L)12640.98 (0.93-1.04)0.517
Hemoglobin (g/dL)12430.85 (0.79-0.91)0.002
Lesion size (cm)12672.03 (1.53-2.70)< 0.001
Dichotomized predictorsa
Age ≥ 80 yr12670.92 (0.70-1.21)0.540
Serum albumin < 35 g/L12662.16 (1.69-2.76)< 0.001
Carcinoembryonic antigen ≥ 20 µg/L12474.33 (3.39-5.54)< 0.001
White blood cell count ≥ 8.5 × 109/L12651.78 (1.40-2.28)0.001
Platelet count ≥ 450 × 103/L12632.36 (1.67-3.35)< 0.001
Serum sodium < 135 mmol/L12641.62 (1.20-2.20)0.002
Serum creatinine ≥ 135 µmol/L12430.56 (0.31-1.02)0.057
Serum potassium < 3.5 mmol/L12671.37 (1.01-1.85)0.043
Serum urea ≥ 7 mmol/L12671.00 (0.71-1.40)0.999
Hemoglobin < 11 g/dL12431.48 (1.16-1.89)0.002
Lesion size ≥ 4 cm12672.03 (1.53-2.70)< 0.001
Table 4 Multivariable model predicting all-cause mortality, truncated at 3 years from time of surgery
VariableHazard ratio2.5thpercentile97.5thpercentileP value
Serum albumin < 35 g/dL1.411.081.830.011
CEA ≥ 20 µg/L2.511.923.28< 0.001
T stage
T1/Tis1.00 (ref)---
T21.110.235.410.894
T36.181.5524.60.010
T417.94.4572.1< 0.001
Tumor grade
Well differentiated1.00 (ref)---
Moderately differentiated2.241.044.820.040
Poorly differentiated or mucinous3.541.548.150.003
Rectal lesion1.471.111.960.007
Chronic obstructive lung disease1.871.113.170.019
Table 5 Comparison between Singapore General Hospital; and Kyungpook National University Chilgok Hospital cohorts
VariableSGH(n = 1267)KNUCH(n = 910)
nn
Age, median (range), yr126777 (70-102)91075 (70-96)
Gender
Male658(51.9)496(54.5)
Female609(48.1)414(45.5)
Lesion sites
Colon790(62.3)540(59.3)
Rectum477(37.6)370(40.7)
Tumor grade
Well differentiated117(9.0)29(3.2)
Moderately differentiated1009(79.6)809(88.9)
Poorly differentiated70(5.5)29(3.2)
Mucinous/signet ring cell71(5.6)43(4.7)
Laboratory parameters, mean (SD)
Creatinine, µmol/L126788.9 (54.9)91083.8 (38.6)
Urea, mmol/L12675.5 (2.7)9102.7 (1.1)
Hemoglobin, g/dL126711.8 (1.8)91012.0 (2.1)
WBC count, × 109/L12677.9 (2.6)9088.0 (18.2)
Platelet count, × 109/L1267300.6 (104.6)910287.1 (95.3)
Serum albumin, g/L111933.7 (5.5)91039.9 (4.6)
CEA, median (IQR), µg/L11964.3 (2.6–14.2)8872.4 (1.5–4.8)
Comorbidities
Diabetes331(26.1)167(18.4)
Hypertension416(32.8)415(45.6)
Ischemic heart disease47(3.7)14(1.5)
Congestive heart failure41(3.2)20(2.2)
PVD30(2.4)0(0.0)
COPD61(4.8)66(7.3)
Previous stroke90(7.1)50(5.5)
End stage renal disease26(2.1)6(0.7)
ASA
1178(14.0)152(16.7)
2857(67.6)724(79.6)
3225(17.8)34(3.7)
47(0.6)0(0.0)
T stagea
Tis2(0.2)8(0.9)
T195(7.5)72(7.9)
T2188(14.8)134(14.7)
T3752(59.4)587(64.5)
T4a97(7.7)76(8.4)
T4b133(10.5)29(3.2)
ypCR0(0.0)4(0.4)
N stagea
N0688(54.3)577(63.4)
N1a148(11.7)124(13.6)
N1b185(14.6)109(12.0)
N1c4(0.3)1(0.1)
N2a99(7.8)58(6.4)
N2b143(11.3)41(4.5)
Short term outcomes
Anastomotic leak16(1.3)44(4.8)
30-d morbidity297(23.4)212(23.3)
30-d mortality30(2.4)1(0.001)