Familial relative risks for breast cancer by pathological subtype: a population-based cohort study

Breast Cancer Research

Table 1 Index case tumour subtypes and distribution of cases according to reported family history

Phenotype of index case tumour	Number of tumours (%)**	Number with affected relative (%)^†	Number without affected relative (%)^‡	Comparison group for case-only analysis	OR^§	95%CI	P-valuee
ER-positive	3659 (81)	599 (82)	3060 (81)	ER-negative	1.04	0.85-1.28	0.70
PR-positive	1709 (69)	267 (69)	1442 (69)	PR-negative	1.01	0.79-1.27	0.96
HER2-positive	228 (12)	38 (13)	190 (12)	HER2-negative	1.15	0.79-1.68	0.78
ER+PR+	1581 (65)	247 (64)	1334 (65)	ER-PR-	1.00	0.75-1.31	0.95
ER-PR+	110 (4.5)	18 (5)	92 (5)
ER+PR-	261 (11)	43 (11)	218 (11)
ER or PR+ (luminal)	3787 (83)	619 (84)	3168 (83)
ER or PR+ HER2+ (luminal HER2+)	138 (7)	23 (8)	115 (7)	luminal HER2-	1.17	0.73-1.88	0.51
ER or PR+ HER2- (luminal HER2-)	1404 (75)	209 (74)	1195 (75)
ER-PR-HER2+ (non-luminal HER2+)	76 (5)	11 (4)	65 (5)	TN	1.02	0.48-2.16	0.96
ER-PR-HER2- (TN)	218 (13)	30 (12)	188 (13)

ER: estrogen receptor; HER2: human epidermal growth factor receptor; PR: progesterone receptor; TN: triple negative.
* reported diagnosis of breast cancer in a first degree relative
** Number of tumours in phenotypic group as a percentage of those tested for that phenotype
† Number of tumours in phenotypic group with an affected first degree relative as a percentage of cancers with measured phenotype and an affected first degree relative
‡ Number of tumours in phenotypic group without any affected first degree relative as a percentage of cancers with measured phenotype and without any affected relative
^§OR, 95% CI (confidence intervals) and P-values associated with family history of breast cancer in any first degree relative, adjusting for age at diagnosis of the index case.

ISSN: 1465-542X