Development and validation of an extended Cox prognostic model for patients with ER/PR+ and HER2− breast cancer: a retrospective cohort study

Table 6 Prognostic factors, coefficients, hazard ratios, and P-values of the Z-tests in the extended Cox model

Variable	Prognostic factor	Coefficient	HR (95% CI)	p-value
x₁	Histological grade (I, II, III)	1.329	3.777 (1.739, 8.204)	< 0.001
x₂	N status (0, 1, 2, 3)	0.972	2.644 (1.872, 3.734)	< 0.001
x₃	Ki67 status (60%)	1.650	5.208 (2.311, 11.738)	< 0.001
x₄	PR status (20%)	−1.802	0.165 (0.050, 0.548)	0.003
x₅	Age (55 years)	1.378	3.968 (1.548, 10.171)	0.004
x₇	Age (41 years)	−1.563	0.210 (0.053, 0.829)	0.026
x₈	PR − age after 164 weeks (Age ≥ 41 years, PR ≥ 20%)	1.594	4.922 (1.039, 23.325)	0.045

HR, hazard ratio, CI, confidence interval. Ki67 status (60%), a binary variable that is one if Ki67 is no less than 60% and zero otherwise. PR status (20%), a binary variable that is one if PR is no less than 20% and zero otherwise. Age (55 years), a binary variable that is one if age is no less than 55 years and zero otherwise. Age (41 years), a binary variable that is one if age is no less than 41 years and zero otherwise. PR-age after 164 weeks (age ≥ 41 years, PR ≥ 20%), a binary variable, an interaction item between age and PR status after 164 weeks after surgery, which is one if age is no less than 41 years old and PR is no less than 20% and zero otherwise

ISSN: 1477-7819