Development and validation of machine learning nomograms for predicting survival in stage IV pancreatic cancer: A retrospective study

Table 2 Univariate Cox regression analysis for cancer-specific survival and overall survival in stage IV pancreatic cancer patients

Variables	OS		CSS
	HR (95%CI)	P value	HR (95%CI)	P value
Age (years)
< 60	1 (reference)		1 (reference)
60-75	1.26 (1.10, 1.45)	0.001	1.25 (1.08, 1.44)	0.002
> 75	1.70 (1.44, 2.02)	< 0.001	1.71 (1.44, 2.03)	< 0.001
Sex
Female	1 (reference)		1 (reference)
Male	0.97 (0.87, 1.09)	0.645	0.98 (0.87, 1.10)	0.730
Race
White	1 (reference)		1 (reference)
Black	1.26 (1.03, 1.54)	0.024	1.20 (0.98, 1.48)	0.078
Other	0.88 (0.72, 1.07)	0.195	0.89 (0.73, 1.08)	0.237
Marital status
Married	1 (reference)		1 (reference)
Unmarried	1.17 (0.99, 1.38)	0.069	1.16 (0.98, 1.38)	0.079
Divorced	1.54 (1.34, 1.77)	< 0.001	1.52 (1.32, 1.76)	< 0.001
Unknown	1.72 (1.28, 2.33)	< 0.001	1.71 (1.26, 2.32)	0.001
Tumor location
Head	1 (reference)		1 (reference)
Body	1.34 (1.13, 1.60)	0.001	1.35 (1.13, 1.61)	0.001
Tail	1.20 (1.02, 1.41)	0.027	1.22 (1.03, 1.43)	0.020
Other	1.42 (1.22, 1.64)	< 0.001	1.42 (1.22, 1.65)	< 0.001
T stage
T1/T2	1 (reference)		1 (reference)
T3	0.76 (0.65, 0.89)	< 0.001	0.77 (0.66, 0.90)	0.001
T4	0.92 (0.77, 1.09)	0.339	0.93 (0.78, 1.11)	0.413
TX	1.13 (0.96, 1.35)	0.148	1.10 (0.92, 1.31)	0.288
N stage
N0	1 (reference)		1 (reference)
N1	0.96 (0.84, 1.09)	0.488	0.98 (0.86, 1.12)	0.789
NX	1.44 (1.22, 1.69)	< 0.001	1.42 (1.20, 1.68)	< 0.001
Grade
Grade I/II	1 (reference)		1 (reference)
Grade III/IV	1.68 (1.37, 2.05)	< 0.001	1.69 (1.38, 2.08)	< 0.001
Unknown	1.74 (1.48, 2.04)	< 0.001	1.72 (1.46, 2.02)	< 0.001
Surgery
No	1 (reference)		1 (reference)
Yes	0.46 (0.38, 0.56)	< 0.001	0.47 (0.38, 0.57)	< 0.001
Chemotherapy
No	1 (reference)		1 (reference)
Yes	0.33 (0.30, 0.38)	< 0.001	0.34 (0.30, 0.38)	< 0.001
Radiotherapy
No	1 (reference)		1 (reference)
Yes	0.76 (0.60, 0.97)	0.027	0.78 (0.61, 0.99)	0.040
Bone metastasis
No	1 (reference)		1 (reference)
Yes	1.10 (0.88, 1.37)	0.397	1.15 (0.92, 1.44)	0.206
Liver metastasis
No	1 (reference)		1 (reference)
Yes	1.49 (1.32, 1.68)	< 0.001	1.50 (1.32, 1.70)	< 0.001
Lung metastasis
No	1 (reference)		1 (reference)
Yes	1.02 (0.89, 1.17)	0.819	1.01 (0.88, 1.16)	0.910

OS: Overall survival; CSS: Cancer-specific survival; HR: Hazard ratio.