Table 2.

Univariate analysis of factors affecting overall survival

	P-value		HRa	95% CI of HR
Variables with a P-value of ≤0.05 (all included in later multivariate analysis)b
Nodal status N1 versus N0	<0.0001		1.89	1.47–2.46
Lymphatic invasion	<0.0001		1.72	1.34–2.20
Histological grade (differentiation)c	0.0002
Moderate versus good		0.032	1.83	1.05–3.18
Poor versus good		0.0008	2.58	1.48–4.49
Venous invasion	0.0096		1.37	1.08–1.73
Age	0.047		1.02	1.01–1.03
Surgical margins	0.010		1.37	1.08–1.75
Tumour sizec	0.0073
2.0–2.9 cm versus <2.0 cm		0.082	1.30	0.97–1.77
3.0–3.9 cm versus <2.0 cm		0.0083	1.55	1.12–2.13
≥4.0 cm versus <2.0 cm		0.0014	1.83	1.26–2.64
Perineural invasion	0.048		1.39	1.003–1.93
ERCP stent	0.075		0.68	0.51–0.90
Surgery type	0.031
Pylorus-sparing versus standard		0.91	1.02	0.71–1.48
Total pancreatectomy versus standard		0.0091	1.76	1.15–2.68
Variables with a P-value of >0.05 but <0.30 (included in later multivariate analysis)
Jaundice on presentation	0.11		1.28	0.98–1.74
Gender (female)	0.20		0.86	0.70–1.08
Vascular resection	0.23		1.16	0.91–1.46
Variables with a P-value of >0.30a (NOT included in later multivariate analysis)
Diabetes mellitus	0.34
Family history of non-GI cancer	0.36
Hypertension	0.36
Family history of pancreatic cancer	0.42
Weight loss	0.42
Race	0.49
CA 19-9 level	0.58
Estimated blood loss	0.61
Tobacco use	0.83
Aspartate transaminase	0.89
Platelet count	0.96
Family history of other GI cancer	0.97

^aHazard ratio and 95% confidence limits given for variables with P < 0.30. A positive value indicates that the variable is associated with a decreased probability of survival.

^bLow haematocrit, bilirubin >20 mg/dl and M status not evaluated by univariate analysis because of low numbers (<5% of total) in one group.

^cP-values for the question of whether levels of risk for all groups are equal (type III test).

HR, hazard ratio; 95% CI, 95% confidence interval; ERCP, endoscopic retrograde cholangiopancreatography; GI, gastrointestinal; CA 19-9, carbohydrate antigen 19-9.