Mammographic density as a predictor of breast cancer survival: the Multiethnic Cohort

Breast Cancer Research

Table 2 Survival and incidence of new breast cancer related to breast density

Outcome	Model	Label	Per 10% density	Percent density^a		Percent density categories
				Low	High	< 25%	25 to < 50%	≥ 50%
Breast cancer death	All	Number	607	304	303	215	209	183
		Deaths	27	12	15	9	7	11
		HR^b	0.95	1	0.83	1	0.60	0.89
		95% CI	0.79-1.15		0.36-1.92		0.22-1.66	0.34-2.33
		P value	0.61		0.67		0.33	0.80
	All plus interaction (density × radiation)	Number	607	304	303	215	209	183
		Deaths	27	12	15	9	7	11
		HR^b	1.38	1	5.31	1	0.96	2.54
		95% CI	0.99-1.92		0.66-43.1		0.33-2.79	0.65-9.88
		P value	0.06		0.12		0.94	0.18
	With radiation	Number	361	175	170	128	131	102
		Deaths	16	11	5	9	2	5
		HR^b	0.77	1	0.33	1	0.19	0.42
		95% CI	0.60-0.99		0.11-1.06		0.04-0.91	0.12-1.40
		P value	0.04		0.06		0.04	0.16
	Without radiation	Number	246	118	128	87	78	81
		Deaths	11	1	10	0	5	6
		HR	1.46	1	5.57		1	1.34
		95% CI	1.00-2.14		0.65-48.0			0.34-5.34
		P value	0.05		0.12			0.68
Other causes of death	All	Number	607	304	303	215	209	183
		Deaths	100	55	45	44	28	28
		HR^b	1.08		1.37		1.06	1.32
		95% CI	0.98-1.20		0.88-2.13		0.64-1.75	0.77-2.25
		P value	0.13		0.16		0.83	0.32
Second breast cancer	All plus interaction (density × radiation)	Number	607	304	303	215	209	183
		Cases	71	32	39	22	23	26
		HR^b	1.13	1	1.72	1	1.31	2.11
		95% CI	0.96-1.33		0.88-2.55		0.69-2.50	0.98-4.50
		P value	0.14		0.15		0.41	0.06

^aLow density = < 35%; high density ≥ 35%. ^bHazard ratios (HRs) and 95% confidence intervals (CIs) for the effect of density estimated by Cox regression with adjustment for age at diagnosis, ethnicity, overweight/obesity, stage of disease at diagnosis (in situ, localized, or advanced), and radiation treatment when applicable.

ISSN: 1465-542X