TABLE 1.
Characteristics of mammography cohort
|
All patients N = 198,278 |
|
|---|---|
| N (%) or Mean (SD) | |
| Age at screening (years) | 54.30 (11.04) |
| Age at screening (categories) | |
| 40–49 | 80,416 (40.6%) |
| 50–59 | 57,717 (29.1%) |
| 60–69 | 38,641 (19.5%) |
| 70+ | 21,504 (10.8%) |
| Prior biopsies | |
| 0 | 176,549 (89.0%) |
| 1 | 17,168 (8.7%) |
| 2 or more | 4561 (2.3%) |
| Atypical hyperplasia | 1734 (0.9%) |
| Age at menarche | |
| <12 | 31,802 (16.0%) |
| 12–13 | 99,978 (50.4%) |
| 14+ | 47,558 (24.0%) |
| Missing | 18,940 (9.6%) |
| Age at first live birth | |
| No births | 42,217 (21.3%) |
| Under 20 | 20,123 (10.1%) |
| 20–24 | 36,625 (18.5%) |
| 25–29 | 41,524 (20.9%) |
| 30 or older | 46,077 (23.2%) |
| Missing | 11,712 (5.9%) |
| Number of relatives with breast cancer | |
| 0 | 173,075 (87.3%) |
| 1 | 22,969 (11.6%) |
| 2+ | 2234 (1.1%) |
| Race/ethnicity | |
| White | 146,159 (73.7%) |
| Black/African American | 29,822 (15.0%) |
| Hispanic/Latino | 6585 (3.3%) |
| Asian/Pacific Islander | 9371 (4.7%) |
| Other/unknown | 6341 (3.2%) |
| BMI | |
| <25 | 76,035 (38.3%) |
| 25–29.9 | 49,461 (24.9%) |
| 30+ | 49,484 (25.0%) |
| Missing | 23,298 (11.8%) |
| Postmenopausal | 115,405 (58.2%) |
| Number of live births | |
| 0 | 42,217 (21.3%) |
| 1 | 41,269 (20.8%) |
| 2 | 52,116 (26.3%) |
| 3 | 28,054 (14.1%) |
| 4+ | 16,032 (8.1%) |
| Missing | 18,590 (9.4%) |
| BI‐RADS breast density | |
| BI‐RADS A | 15,348 (7.7%) |
| BI‐RADS B | 76,196 (38.4%) |
| BI‐RADS C | 87,459 (44.1%) |
| BI‐RADS D | 15,740 (7.9%) |
| Unknown | 3535 (1.8%) |
| Site | |
| MGH | 79,671 (40.2%) |
| NWH | 52,331 (26.4%) |
| Penn | 66,276 (33.4%) |
| Breast cancers | |
| DCIS | 1158 (22.4%) |
| Total invasive | 4002 (77.6%) |
| Invasive ER/PR+HER2− | 3077 (76.9%) |
| Invasive triple negative | 300 (7.5%) |
| Invasive ER/PR+HER2+ | 342 (8.5%) |
| Invasive ER/PR−HER2+ | 126 (3.2%) |
| Invasive missing | 157 (3.9%) |
Abbreviations: ER/PR, estrogen receptor/progesterone receptor; HER2, human epidermal growth factor receptor 2; MGH, Massachusetts General Hospital; NWH, Newton‐Wellesley Hospital.