Predictive value of indirect bilirubin before neoadjuvant chemoradiotherapy in evaluating prognosis of local advanced rectal cancer patients

Table 2 Cox regression analysis of prognostic factors for overall survival

Characteristic	Univariable analysis		Multivariable analysis
	HR (95%CI)	P value	HR (95%CI)	P value
Pre-IBIL
≤ 6.2 μmol/L	Reference		Reference
> 6.2 μmol/L	1.71 (1.01-2.87)	0.045	1.77 (1.04-3.01)	0.035
Age, yr
< 60	Reference
≥ 60	1.39 (0.84-2.31)	0.199
Sex
Female	Reference
Male	1.16 (0.66-2.04)	0.596
BMI, kg/m2
< 18.5	Reference
18.5-23.9	0.74 (0.23-2.43)	0.624
24.0-27.9	0.57 (0.17-1.93)	0.370
≥ 28.0	0.27 (0.05-1.32)	0.105
Smoking history
No	Reference		Reference
Yes	0.57 (0.34-0.97)	0.039	0.58 (0.34-1.00)	0.048
Drinking history
No	Reference
Yes	0.72 (0.42-1.23)	0.227
Chronic disease history
No	Reference
Yes	1.09 (0.65-1.82)	0.749
cTNM stage
II	Reference
III	2.54 (0.92-6.99)	0.072
nCRT with surgery interval, day
31-60	Reference
61-90	0.61 (0.35-1.07)	0.083
> 90	0.68 (0.24-1.92)	0.469
Inferior margin
≤ 5 cm	Reference
> 5 cm	0.91 (0.53-1.59)	0.752
TRG
1	Reference		Reference
2	0.35 (0.18-0.67)	0.002	0.37 (0.18-0.75)	0.006
3	0.23 (0.10-0.52)	< 0.001	0.27 (0.12-0.64)	0.003
4	0.17 (0.06-0.48)	< 0.001	0.18 (0.06-0.53)	0.002
Vascular invasion
Negative	Reference		Reference
Positive	3.79 (1.86-7.74)	< 0.001	2.93 (1.39-6.21)	0.005
Neural invasion
Negative	Reference		Reference
Positive	2.15 (1.26-3.69)	0.005	1.27 (0.69-2.31)	0.442
Radiotherapy type before surgery
VMAT	Reference
IMRT	1.68 (0.85-3.35)	0.137
3D-CRT	0.69 (0.09-4.98)	0.709
Chemotherapy type before surgery
Capecitabine	Reference
Capecitabine + platinum	1.45 (0.57-3.66)	0.431
Other	1.90 (0.76-4.78)	0.172
Adjuvant chemotherapy
No	Reference
Yes	0.60 (0.36-1.00)	0.050
Pre-CEA
≤ 5 ng/mL	Reference
> 5 ng/mL	1.44 (0.87-2.39)	0.158
Pre-CA19-9
≤ 27 U/mL	Reference		Reference
> 27 U/mL	2.05 (1.19-3.54)	0.010	2.05 (1.16-3.62)	0.014

HR: Hazard ratio; 95%CI: 95% confidence interval; nCRT: Neoadjuvant chemoradiotherapy; pre-IBIL: Indirect bilirubin before neoadjuvant chemoradiotherapy; BMI: Body mass index; TRG: Tumor regression grade; VMAT: Volumetric modulated arc therapy; IMRT: Intensity modulated radiation therapy; 3D-CRT: 3-dimensional conformal radiation therapy; pre-CEA: Carcinoembryonic antigen before neoadjuvant chemoradiotherapy; pre-CA19-9: Carbohydrate antigen 19-9 before neoadjuvant chemoradiotherapy.