Table 3.

Univariate analysis of prognostic factors for OS and DFS

Variables	Median OS (mo)	P value	Median DFS (mo)	P value
Tumor size
≤ 3 cm	35.2	< 0.001	19.8	< 0.001
> 3 cm	14.7		13.0
Surgical procedures
BDR	20.8	0.072	15.0	0.065
BDR + hepatectomy	27.6		18.7
Lymph node metastasis
N0	39.9	< 0.001	25.4	< 0.001
N1-2	15.7		12.3
Tumor differentiation
Well	54.1	< 0.001	25.3	< 0.001
Moderate	27.6		17.8
Poor	13.5		12.1
Resection margin
R0	35.2	< 0.001	20.6	< 0.001
R1 and R2	12.4		9.6
Presence of vascular invasion
No	26.3	0.009	19.0	< 0.001
Yes	20.9		10.6
Caudate lobe resection
Yes	35.7	0.040	21.3	< 0.001
No	21.4		15.0
CA 19-9 > 100 U/L
No	39.7	0.039	23.6	0.018
Yes	23.0		16.7
Perineural infiltration
No	27.3	0.084	22.7	0.090
Yes	20.8		15.9
T stage (AJCC)
T1 and T2	27.6	NS	19.2	0.028
T3 and T4	25.7		16.9

Additional factors not significant in univariate analysis included age, sex, gross feature, operative time, total hospital stay, preoperative biliary drainage, and Bismuth-Corlett classification. AJCC: American Joint Committee on Cancer; BDR: Hilar bile duct resection; CA: Carbohydrate antigen; DFS: Disease-free survival; NS: Not significant; OS: Overall survival.