Table 1

Comparison of breast cancer risk factors and breast tumour characteristics according to those who were eligible for the study, those for whom we received pathology specimens and those who were included in the tissue microarrays, Nurses' Health Study (1976 to 1996)


Eligible for TMA (n = 5610)
Received pathology specimens (n = 3752)
Included in TMA (n = 2897)

Means



Age at diagnosis, y
56.4
57.4
57.5
Age at menarche, y
12.4
12.4
12.4
Age at first birth, y
25.4
25.4
25.3
Age at menopause, y
46.9
47.1
47.1
BMI at age 18, kg/m2
21.0
21.0
21.0
Parity
3.2
3.2
3.2
Alcohol g/week
6.6
6.1
6.2




Frequencies, n (%)



Family history of BC
805 (14.4)
559 (14.9)
409 (14.1)
Nulliparous
430 (7.7)
281 (7.5)
211 (7.3)
Premenopausal
1345 (24.0)
782 (20.8)
600 (20.7)
Prior BBD
2662 (47.5)
1852(49.4)
1360 (47.0)
Current PMH user
1239 (33.8)
884 (34.2)
688 (34.6)




Year of diagnosis



1976 to 1980
517 (9.4)
223 (6.1)
158 (5.6)
1980 to 1985
1066 (19.4)
565 (15.4)
431 (15.2)
1985 to 1990
1678 (30.6)
1152 (31.3)
899 (31.6)
1990 to 1996
2230 (40.6)
1739 (47.3)
1357 (47.7)




Tumour characteristicsa



DCIS
654 (11.7)
443 (11.8)
270 (9.3)
Invasive
4956 (88.3)
3309 (88.2)
2627 (90.7)




Tumour size



Less than 2 cm
3162 (65.6)
2197 (66.7)
1685 (64.9)
More than 2 cm
1656 (34.4)
1098 (33.3)
911 (35.1)




Grade



Well differentiated
319 (15.2)
240 (16.2)
176 (14.7)
Moderately
860 (41.0)
630 (42.4)
515 (43.1)
Poorly
919 (43.8)
615 (41.4)
505 (42.2)




Nodal involvement



No nodes
3931 (70.1)
2684 (71.5)
2006 (69.2)
1 to 3 nodes
904 (16.1)
585 (15.6)
485 (16.7)
4 to 9 nodes
428 (7.6)
268 (7.1)
213 (7.4)
More than 10 nodes
228 (4.1)
140 (3.7)
129 (4.5)
Metastatic
119 (2.1)
75 (2.0)
64 (2.2)




Receptor status



ER+
2738 (74.5)
1953 (75.2)
1572 (75.3)
PR+
2083 (61.2)
1518 (61.9)
1235 (62.3)

aTumour characteristics abstracted from medical pathology reports. BC, breast cancer; BBD, benign breast disease; BMI, body mass index; DCIS, ductal carcinoma in situ; ER, oestrogen receptor; PMH, postmenopausal hormone; PR, progesterone receptor; TMA, tissue microarrays.

Tamimi et al. Breast Cancer Research 2008 10:R67   doi:10.1186/bcr2128