Table 3 Univariate and multivariate analysis of Disease-free Survival (DFS) in PDAC patients (n = 161)

Age

< 60 (ref)

≥ 60

1.125

0.820-1.545

0.461

Gender

Male (ref)

Female

0.874

0.637-1.200

0.402

Differentiation

Well (ref)

Moderate

1.878

1.112-3.171

0.047^*

1.688

0.862-3.306

0.127

Poor

2.131

1.251-3.630

0.020^*

1.824

0.903-3.688

0.094

TNM stage

I (ref)

II

1.279

0.867-1.886

0.236

0.996

0.642-1.544

0.986

III

1.744

0.980-3.104

0.032^*

1.142

0.629-2.075

0.662

Lymph node metastasis ^a

Negative (ref)

Positive

1.627

1.185-2.234

0.002^**

Perineural invasion

Negative (ref)

Positive

1.269

0.824-1.955

0.310

Long-term smoking ^b

No (ref)

Yes

1.788

0.989-3.232

0.013^*

2.151

1.305-3.545

0.003^**

High-fat diet

No (ref)

Yes

1.395

0.845-2.304

0.136

Chronic pancreatitis

No (ref)

Yes

1.471

0.899-2.407

0.073

circCUL2 expression

Low (ref)

High

1.982

1.418-2.771

<0.001^***

2.073

1.460-2.942

<0.001^***

Abbreviations: HR = hazard ratio; 95% CI = 95% confidence interval; TNM = tumor node metastasis; ref = reference. ^a As lymph node metastasis is included in the TNM stage, we didn’t include it in the multivariate analysis. ^b Long-term smoking (duration ≥ 29 years). Cox regression analysis, * p < 0.05, ** p < 0.01, *** p<0.001.