Contralateral Risk-Reducing Mastectomy: Review of Risk Factors and Risk-Reducing Strategies

Table 1

Risk factors for developing CBC (estimated annual risk) [4, 7].

	Estimated annual risk (%) [4]	Relative risk—multivariate (95% CI) [7]
Patient factors
Age at first diagnosis
<30 yrs	0.5–1.3
40–50 yrs
ER +ve	0.2-0.3
ER −ve	0.4-0.5
Gene mutation
BRCA1	2.0–3.0
BRCA2	2.0–3.0
Family history
None		1 (reference)
First- and second-degree	0.4–1.3	2.8 (1.4–5.5)
First-degree	0.2–0.8	1.4 (0.9–2.1)
Second- or third-degree	Baseline	1.1 (0.7–1.9)
Tumour factors
Size
<2 cm (T1)		1 (reference)
2–5 cm (T2)		1.5 (1.1–2.0)
>5 cm (T3)		1.9 (1.1–3.3)
LN status
None		1 (reference)
1–3		0.9 (0.6–1.2)
4–9		1.1 (0.7–1.9)
>10		1.6 (0.8–3.1)
Histology
Ductal		1 (reference)
Lobular		1.2 (0.6–2.1)
ER status
ER positive		1.0 (reference)
ER negative		1.3 (0.9–1.9)
HER2 status
HER2 positive		1.0 (reference)
HER2 negative		1.02 (0.6–1.8)