Analysis of incidence and prognostic factors for ipsilateral breast tumour recurrence and its impact on disease-specific survival of women with node-negative breast cancer: a prospective cohort study

Table 2 Results of IBTR-free survival analysis by univariate and multivariate Cox proportional hazards models

Prognostic variable	Univariate			Multivariate
	RR	95% CI	p	RR	95% CI	P
Age at primary diagnosis^a	1.50	0.83–2.75	0.18	1.89	1.00–3.58	0.05
Intraductal (yes versus else)	1.69	1.09–2.64	0.02	1.81	1.15–2.85	0.01
Multicentricity (yes versus else)	2.10	1.15–3.84	0.02	1.54	0.83–2.85	0.17
Histological grade
'G2' & GG3 versus G1	1.39	0.76–2.53	0.29	1.59	0.87–2.94	0.13
Not done and don't know versus G1	2.50	1.29–4.85	0.01	2.40	1.23–4.67	0.01
Tumour size
1–2 cm versus <1 cm	1.12	0.70–1.80	0.64
>2 cm versus <1 cm	1.18	0.69–2.01	0.55
Oestrogen receptor status^b	0.87	0.52–1.47	0.61
Progesterone receptor status^b	1.46	0.97–2.21	0.07
Menopausal status^c	1.12	0.74–1.70	0.58
Vascular invasion (yes versus else)	0.59	0.15–2.39	0.46
Lymphatic invasion (yes versus else)	0.97	0.53–1.78	0.48
Radiation therapy versus none	0.30	0.20–0.45	<0.000001	0.29	0.19–0.44	<0.000001
Adjuvant treatment
Hormone therapy versus none	0.62	0.41–0.93	0.02	0.56	0.36–0.85	0.01
Chemotherapy versus none	0.47	0.22–1.02	0.06	0.45	0.20–1.02	0.06

98 IBTRs among 1,540 eligible women. IBTR, ipsilateral breast tumour recurrence; CI, confidence interval; RR, relative risk. ^aAge < 40 years versus age ≥ 40 years; ^bnegative and equivocal versus positive and don't know and not done; ^cpremenopausal and perimenopausal aged < 50 years versus postmenopausal and perimenopausal aged ≥ 50 years.

ISSN: 1465-542X