MRI background parenchymal enhancement, fibroglandular tissue, and mammographic breast density in patients with invasive lobular breast cancer on adjuvant endocrine hormonal treatment: associations with survival

Table 4 Cox regression models using recurrence-free survival as the main outcome of interest after backward selection

	Covariate: BPE		Covariate: BPE (limited subset)		Covariate: FGT
	Log (HR)	p value	Log (HR)	p value	Log (HR)	p value
Age	0.06	0.002	0.06	0.05	0.07	0.01
Hormonal treatment duration
1–5 years	2.82	0.001	2.33	0.001	3.02	< .0001
≥ 6 years	Ref		Ref		Ref
Number of metastatic lymph nodes
> 3	4.50	< .0001	4.12	< .0001	5.04	< .0001
Micro to 3	1.08	0.10	0.52	0.54	1.45	0.03
Non-metastatic	Ref		Ref		Ref
Histology
Classic	−2.02	0.001	−0.62	0.28	− 2.26	< .0001
Mixed	−2.06	0.05	1.16	0.03	− 3.29	0.06
Pleomorphic	Ref		Ref		Ref

Limited subset: Only individuals with mild/moderate/significant parenchymal enhancement were included in the limited subset analysis
Abbreviations: BPE background parenchymal enhancement, FGT fibroglandular tissue, HR hazard ratio

ISSN: 1465-542X