Table 2.

Predictive factors for disease-free survival.

Factors	No.	Median, months	95% CI	P-value
Gender				0.68
Male	120	34.0	0-80.1
Female	92	33.7	0-75.2
Age (years)				0.53
≤60	99	33.7	0-86.6
>60	113	30.3	5.3-55.4
Charlson comorbidity index				0.29
≤3	166	39.2	0-82.5
>3	46	26.3	13.2-39.4
WHO performance status				0.23
0~1	199	31.8	11.6-51.9
2	13	n/a	n/a
Operation type				0.64
PPPD	100	39.2	0-91.2
PD	112	30.3	7.8-52.9
Differentiation				0.005
Well	51	n/a	n/a
Moderate/poor	161	24.5	15.0-34.0
AJCC 7th T classification				<0.001
T1/T2	98	n/a	n/a
T3	114	18.2	12.3-24.1
AJCC 7th N classification				<0.001
N0	108	n/a
N1	104	15.0	6.7-60.8
Microscopic resection margin
Negative	205	83.8	72.6-94.9	0.71
Positive	7	101.9	40.3-136.3
Lymphovascular invasion				<0.001
Negative	132	n/a	n/a
Positive	80	14.8	9.3-20.3
Perineural invasion				<0.001
Negative	161	67.9	n/a
Positive	51	10.0	4.5-15.5
Adjuvant chemotherapy				<0.001
Yes	111	17.9	11.6-24.1
No	101	n/a	n/a

CI, confidence interval; PPPD, pylorus-preserving pancreaticoduodenectomy; PD, pancreaticoduodenectomy; n/a, not available; WHO, World Health Organization; AJCC, American Joint Committee on Cancer.