Preoperative risk stratification of early recurrence in resected pancreatic ductal adenocarcinoma: Novel equilibrium-phase-computed tomography biomarker of extracellular volume

Table 2 Univariate and multivariate analyses for early recurrence in patients with pancreatic ductal adenocarcinoma

Variable	Univariate analysis		Multivariate analysis
	Hazard ratio (95%CI)	P value	Hazard ratio (95%CI)	P value
Age (years)	1.008 (0.974-1.042)	0.660
Male sex	0.842 (0.429-1.650)	0.616
Postoperative adjuvant therapy	0.734 (0.423-1.274)	0.272
CA19-9 (U/mL)	1.001 (1.000-1.001)	0.050	1.000 (1.000-1.001)	0.002a
Tumor location		0.131
Head	1 (Reference)
Body to tail	0.404 (0.125-1.310)
Tumor size (cm)	1.196 (0.959-1.492)	0.112
T stage		0.003		0.319
T1	1 (Reference)		1 (Reference)
T2 + T3	3.256 (1.499-7.071)		1.556 (0.652-3.712)
N, yes	1.211 (0.578-2.539)	0.612
Tumor grade, G3	2.542 (1.352-4.780)	0.004	2.506 (1.204-5.215)	0.014a
AJCC tumor stage		0.942
I	1 (Reference)
II/III	0.975 (0.498-1.912)
CT findings of the pancreas
Ill-defined margins	0.987 (0.511-1.905)	0.968
Main pancreatic duct dilation	0.895 (0.485-1.652)	0.723
Parenchymal atrophy	1.306 (0.654-2.609)	0.449
Vein abutment	1.778 (0.954-3.313)	0.070	2.099 (0.977-4.510)	0.057
Peripancreatic tumor infiltration	0.762 (0.441-1.315)	0.329	0.879 (0.530-1.457)	0.616
ΔHUtumor	0.974 (0.958-0.990)	0.002	0.988 (0.965-1.013)	0.340
CT-derived ECV (%)	1.057 (1.025-1.090)	0.001	1.050 (1.017-1.085)	0.003a

^aP < 0.05.

CA19-9: Carbohydrate antigen 19-9; ECV: Extracellular volume; HU: Hounsfield unit; CT: Computed tomography; AJCC: American Joint Committee on Cancer; ΔHU_tumor: Absolute enhancement of the tumor attenuation between the unenhanced and equilibrium-phase computed tomography images; N: Lymph nodes; CI: Confidence interval; G3: Poorly differentiated.