Contralateral prophylactic mastectomy rate stable at major Canadian breast cancer center

Table 1 Patient characteristics

	UM	CPM	P value
	n = 759 (94%)	n = 52 (6%)
Age (median years, range)	52 (28-88)	49 (29-67)	< 0.001
Pre-operative diagnosis (%)			0.74
Invasive carcinoma only	585 (77.1)	38 (73.1)
DCIS only	144 (19.0)	12 (23.1)
Invasive + DCIS	30 (4.0)	2 (3.8)
Previous benign disease (%)			0.26
No	566 (74.6)	34 (65.4)
Yes	164 (21.6)	15 (28.8)
Unknown	29 (3.8)	3 (5.8)
Pre-op BRCA1/BRCA2 mutation status (%)			< 0.001
Negative	43 (6)	9 (17)
Positive	6 (1)	11 (21)
Both unknown	710 (94)	32 (62)
Family history (%)			< 0.001
Positive	283 (37.3)	35 (67.3)
Negative	440 (58.0)	13 (25.0)
Unknown	36 (4.7)	4 (7.7)
Pre-op systemic therapy (%)			0.23
No	588 (77)	36 (69)
Yes	171 (23)	16 (31)
Any radiation treatment (%)			0.008
No	435 (57)	40 (77)
Yes	324 (43)	12 (23)
SLNB (%)			0.76
No	316 (42)	20 (38)
Yes	443 (58)	32 (62)
ALND (%)			< 0.001
No	387 (51)	10 (19)
Yes	372 (49)	42 (81)
Reconstruction (%)			< 0.001
No	695 (92)	24 (46)
Yes	64 (8)	28 (54)
Local/regional recurrence (%)			0.68
No	734 (97)	50 (96)
Yes	25 (3)	2 (4)
New contralateral breast cancer (%)			0.05
No	746 (98)	49 (94)
Yes	13 (2)	3 (6)
Follow-up (median years, range)	2.32 (0.04-7.15)	2.54 (0.13-6.91)	0.56

UM: Unilateral mastectomy; CPM: Contralateral prophylactic mastectomies; BRCA: Breast cancer; SLNB: Sentinel lymph node biopsy; ALND: Axillary lymph node dissection; DCIS: Ductal carcinoma in situ.

Table 2 Multivariable analysis

Predictor	OR	95%CI	P value
Age			0.99
< 50	1	0.52-1.90
≥ 50	Ref	Ref
Family history			< 0.001
Yes	3.56	1.83-7.30
No	Ref	Ref
History of benign disease			0.51
Yes	1.26	0.61-2.49
No	Ref	Ref
Immediate reconstruction			< 0.001
Yes	10.01	5.22-19.32
No	Ref	Ref