Table 2.

Prospectively ascertained breast cancer cases among ProF-SC participants

	Unaffected at baseline	Affected at baseline
Number of women with self-reported new breast cancers	1093	1252
New breast cancers confirmed by pathology, n (%)	848 (78%)	883 (71%)
New breast cancers with blood/buccalsample collected, n (%)	961 (88%)	1184 (95%)
Age at diagnosis of new breast cancer (years), n (%)
<40	117 (11%)	103 (8%)
40–44	107 (10%)	120 (10%)
45–49	147 (13%)	131 (10%)
50–54	128 (12%)	205 (16%)
55–59	132 (12%)	186 (15%)
60–64	135 (12%)	181 (14%)
65–69	98 (9%)	129 (10%)
≥70	199 (18%)	185 (15%)
Unknown	30 (3%)	12 (1%)