Retrospective Study
Copyright ©The Author(s) 2023.
World J Gastrointest Surg. May 27, 2023; 15(5): 892-905
Published online May 27, 2023. doi: 10.4240/wjgs.v15.i5.892
Table 1 Patient demographics, clinicopathologic, and surgical characteristics
Variable
Total, n (%)
Training cohort, n (%)
Validation cohort, n (%)
P value
Total case295177118
Follow-up period (mo)
    Median (IQR)22.68 (13.54, 37.00)23.43 (14.04, 37.00)21.00 (12.93, 37.75)0.798
Age (yr)
    Median (IQR)83 (81, 86)82 (81, 86)83 (81, 86)0.738
    80-89269 (91.19)161 (90.96)108 (91.53)0.867
    90-9926 (8.81)16 (9.04)10 (8.47)
Sex
    Male135 (45.76)81 (45.76)54 (45.76)0.998
    Female160 (54.24)96 (54.24)64 (54.24)
Race
    Chinese274 (92.88)165 (93.22)109 (92.37)0.491
    Malay6 (2.03)3 (1.69)3 (2.54)
    Indian9 (3.06)4 (2.26)5 (4.24)
    Others6 (2.03)5 (2.83)1 (0.85)
ASA classification
    12 (0.68)1 (0.56)1 (0.85)0.599
    290 (30.51)52 (29.38)38 (32.20)
    3187 (63.39)112 (63.28)75 (63.56)
    416 (5.42)12 (6.78)4 (3.39)
BMI (kg/m2)
    Median (IQR)22.43 (19.82, 25.68)22.51 (20.08, 25.82)22.23 (19.31, 25.19)0.480
    ≥ 18.5252 (85.42)154 (87.01)98 (83.05)0.346
    < 18.543 (14.58)23 (12.99)20 (16.95)
Smoking
    No281 (95.25)170 (96.05)111 (94.07)0.434
    Yes14 (4.75)7 (3.95)7 (5.93)
Congestive heart failure within 30 d
    No289 (97.97)174 (98.31)115 (97.46)0.686
    Yes6 (2.03)3 (1.69)3 (2.54)
COPD
    No291 (98.64)174 (98.31)117 (99.15)0.652
    Yes4 (1.36)3 (1.69)1 (0.85)
Diabetes mellitus
    No217 (73.56)133 (75.14)84 (71.19)0.451
    Yes78 (26.44)44 (24.86)34 (28.81)
Preoperative dialysis dependent
    No291 (98.64)174 (98.31)117 (99.15)0.652
    Yes4 (1.36)3 (1.69)1 (0.85)
CCI
    02 (0.68)1 (0.56)1 (0.85)0.118
    1-298 (33.22)50 (28.25)48 (40.68)
    3-462 (21.02)40 (22.60)22 (18.64)
    ≥ 5133 (45.08)86 (48.59)47 (39.83)
Serum albumin (g/dL)
    Median (IQR)3.6 (3.2, 3.9)3.6 (3.1, 3.9)3.6 (3.2, 3.9)0.316
    ≥ 3.0261 (88.48)160 (90.40)101 (85.59)0.209
    2.5-3.027 (9.15)12 (6.78)15 (12.71)
    < 2.57 (2.37)5 (2.82)2 (1.70)
Priority of operation
    Elective206 (69.83)121 (68.36)85 (72.03)0.501
    Emergency89 (30.17)56 (31.64)33 (27.97)
Method of operation
    Open135 (45.76)80 (45.20)55 (46.61)0.812
    Minimally invasive surgery160 (54.24)97 (54.80)63 (53.39)
Type of operation
    Right hemicolectomy110 (37.29)65 (36.72)45 (38.14)0.942
    Left hemicolectomy8 (2.71)5 (2.83)3 (2.54)
    High anterior resection86 (29.15)51 (28.81)35 (29.66)
    Low anterior resection52 (17.63)30 (16.95)22 (18.64)
    Subtotal/total colectomy13 (4.40)10 (5.65)3 (2.54)
    Abdominoperineal resection12 (4.07)7 (3.95)5 (4.24)
    Hartmann's procedure14 (4.75)9 (5.09)5 (4.24)
Stoma
    No205 (69.49)123 (69.49)82 (69.49)0.529
    Loop ileostomy23 (7.80)10 (5.65)13 (11.02)
    End ileostomy6 (2.03)5 (2.82)1 (0.85)
    Ileo-colostomy8 (2.71)5 (2.82)3 (2.54)
    Loop colostomy19 (6.44)12 (6.78)7 (5.93)
    End colostomy34 (11.53)22 (12.44)12 (10.17)
TNM staging
    I61 (20.68)40 (22.60)21 (17.80)0.274
    II88 (29.83)50 (28.25)38 (32.20)
    III129 (43.73)80 (45.20)49 (41.53)
    IV17 (5.76)7 (3.95)10 (8.47)
Postoperative anastomotic leak
    No289 (97.97)173 (97.74)116 (98.31)0.999
    Yes6 (2.03)4 (2.26)2 (1.69)
Postoperative pneumonia
    No276 (93.56)165 (93.22)111 (94.07)0.771
    Yes19 (6.44)12 (6.78)7 (5.93)
Postoperative myocardial infarction
    No288 (97.63)172 (97.18)116 (98.31)0.706
    Yes7 (2.37)5 (2.82)2 (1.69)
Postoperative 30-d readmission
    No255 (86.44)154 (87.01)101 (85.59)0.729
    Yes40 (13.56)23 (12.99)17 (14.41)
Postoperative 30-d mortality
    No289 (97.97)175 (98.87)114 (96.61)0.222
    Yes6 (2.03)2 (1.13)4 (3.39)
Postoperative 1-yr mortality
    No206 (69.83)124 (70.06)82 (69.49)0.918
    Yes89 (30.17)53 (29.94)36 (30.51)
Table 2 Univariate and multivariate Cox regression on predictors for the overall survival of elderly colorectal cancer patients undergoing surgery
Univariate
Multivariate
HR (95%CI)
P value
HR (95%CI)
P value
Age11.08 (1.02-1.14)0.0051.10 (1.04-1.17)< 0.001
Age
    80-89Reference
    90-991.31 (0.63-2.73)0.470--
BMI (kg/m2)
    ≥ 18.5ReferenceReference
    < 18.51.93 (1.12-3.33)0.0181.93 (1.05-3.53)0.034
Serum albumin (g/dL)
    ≥ 3.0ReferenceReference
    2.5-3.01.75 (0.90-3.44)0.1011.18 (0.55-2.54)0.672
    < 2.57.15 (2.82-18.2)< 0.0015.04 (1.82-13.9)0.002
TNM staging
    I, II, and IIIReferenceReference
    IV3.95 (2.07-7.55)< 0.0012.06 (0.95-4.49)0.068
CCI11.34 (1.21-1.48)< 0.0011.41 (1.25-1.59)< 0.001
Priority of operation
    ElectiveReferenceReference
    Emergency1.81 (1.13-2.88)0.0131.35 (0.78-2.33)0.278
Postoperative pneumonia
    NoReferenceReference
    Yes3.46 (1.77-6.78)< 0.0012.99 (1.43-6.23)0.004
Postoperative myocardial infarction
    NoReferenceReference
    Yes6.01 (2.17-16.6)< 0.0014.09 (1.37-12.2)0.012