Early chemotherapy after endoscopic retrograde cholangiopancreatography and survival in advanced pancreatic cancer with biliary obstruction

Table 1 Baseline characteristics of the 30-day landmark endoscopic retrograde cholangiopancreatography cohort, median (interquartile range)/n (%)

Baseline characteristics	Unweighted			IPTW-weighted
	No chemo by day 30	Chemo by day 30	|SMD|	No chemo by day 30	Chemo by day 30	|SMD|(IPTW)
Patients (n)	25	36		22.421	35.851
Age (years)	59.37 (10.23)	57.70 (8.86)	0.175	58.33 (8.99)	57.62 (9.23)	0.104
Female	9 (36.0)	17 (47.2)	0.112	9.6 (49.2)	16.4 (45.9)	0.030
Stage IV	14 (56.0)	24 (66.7)	0.107	13.5 (60.2)	21.7(60.4)	0.002
KPS score	86.20 (7.40)	84.44 (10.40)	0.194	84.89 (7.10)	84.28 (9.65)	0.068
Liver metastasis	10 (40.0)	14 (38.9)	0.011	10.2 (45.3)	14.3 (39.9)	0.054
TBil (μmol/L)	214.1 (158.0, 325.6)	147.25 (92.00, 193.85)	0.741	191.30 (147.60, 307.80)	162.60 (112.90, 268.80)	0.208
Albumin (g/L)	39.42 (4.54)	39.86 (4.58)	0.095	39.60 (4.26)	39.71 (4.69)	0.023
CA19-9 (U/mL)	276.00 (51.41, 3232.00)	983.40 (215.12, 3250.50)	0.179	242.50 (51.41, 3232.00)	985.90 (216.00, 4874.00)	0.034
CEA (ng/mL)	8.50 (4.83, 16.00)	3.71 (2.55, 18.03)	0.168	8.50 (4.83, 13.61)	3.65 (2.62, 18.58)	0.060
CRP (mg/L)	9.55 (6.38, 20.38)	10.14 (4.33, 22.56)	0.115	12.64 (6.38, 20.38)	11.14 (6.27, 22.29)	0.074
WBC (× 109/L)	6.75 (2.33)	6.95 (4.07)	0.060	6.61 (2.30)	6.87 (3.76)	0.079
GGT (U/L)	634.60 (367.00, 874.90)	493.25 (211.97, 768.60)	0.138	550.40 (368.20, 909.20)	596.60 (280.90, 1200.70)	0.066
ALT (U/L)	204.00 (116.60, 288.10)	200.30 (98.05, 297.45)	0.092	204.00 (115.60, 288.10)	211.40 (98.10, 296.40)	0.018

¹Weighted patient numbers represent weighted sample sizes rather than actual case counts.

Baseline variables were defined at or before index endoscopic retrograde cholangiopancreatography. Continuous variables are presented as median (interquartile range), as appropriate, and categorical variables are presented as n (%) or weighted percentages. Stabilized inverse probability of treatment weighting with 1% and 99% truncation was used. Covariate balance was assessed using the absolute standardized mean difference. IPTW: Inverse probability of treatment weights; SMD: Standardized mean difference; KPS: Karnofsky Performance Status; TBil: Total bilirubin; CRP: C-reactive protein; CA19-9: Carbohydrate antigen 19-9; CEA: Carcinoembryonic antigen; WBC: White blood cell; GGT: Gamma-glutamyl transferase; ALT: Alanine aminotransferase.

Table 2 Multivariable model for chemotherapy initiation within 30 days

Variable	OR (95%CI)	P value
Baseline TBil (μmol/L)	0.28 (0.09-0.73)	0.008
Baseline CRP (mg/L)	1.04 (0.56-1.97)	0.892
KPS/10	0.85 (0.43-1.57)	0.615
Baseline albumin (g/L)	0.98 (0.85-1.11)	0.707
Stage IV	1.80 (0.59-5.67)	0.297

The outcome was chemotherapy initiation within 30 days after endoscopic retrograde cholangiopancreatography. Odds ratios and 95%CIs were estimated using Firth penalized logistic regression. Baseline total bilirubin and C-reactive protein were log-transformed for modeling, and Karnofsky Performance Status score was scaled per 10-point increase. Stage III/Locally advanced disease was used as the reference category for stage. An odds ratio > 1 indicates a higher likelihood of chemotherapy initiation within 30 days, whereas an odds ratio < 1 indicates a lower likelihood. KPS: Karnofsky Performance Status; TBil: Total bilirubin; CRP: C-reactive protein; OR: Odds ratio.