Table 1.

Characteristics of 546 women with invasive breast cancer stratified by breast density

CharacteristicsFatty breasts (n = 373), n (%)Dense breasts (n = 173), n (%)
Age at diagnosis (y)
    <5031 (8.3)37 (21.4)
    50-5972 (19.3)51 (29.5)
    60-69120 (32.2)51 (29.5)
    ≥70150 (40.2)34 (19.7)
Age at first birth (y)
    Nulliparous42 (11.3)42 (24.3)
    <2048 (12.9)25 (14.5)
    20-24148 (39.7)38 (22.0)
    25-2993 (24.9)39 (22.5)
    ≥3042 (11.3)29 (16.8)
Age at menopause (y)
    Premenopausal/perimenopausal36 (10.0)41 (23.8)
    <4580 (22.2)30 (17.4)
    45-49119 (33.1)55 (32.0)
    50-5492 (25.6)34 (19.8)
    ≥5533 (9.2)12 (7.0)
BMI quartiles (kg/m2)
    <18.52 (0.5)5 (2.9)
    18.5-24.9149 (39.9)117 (67.6)
    25.0-29.9132 (35.4)31 (17.9)
    ≥3090 (24.1)20 (11.6)
AJCC stage at diagnosis
    I256 (71.7)99 (60.0)
    IIA/IIB73 (20.4)47 (28.5)
    III/IV28 (7.8)19 (11.5)
Interval cancer*
    Interval cancer73 (19.6)78 (45.1)
    Screen detected300 (80.4)95 (54.9)
  • * Interval cancer defined as a cancer diagnosed within 24 months of a negative mammogram (BIRADS codes 1 and 2) and before the next screening examination.