Table 1.
Characteristics of breast cancer cohort.
| Variable | Value | Total |
|---|---|---|
| Overall | 812,851 | |
| Year of diagnosis (cat.) | 1990–1994 | 66,862 (8.2%) |
| 1995–1999 | 90,417 (11.1%) | |
| 2000–2004 | 198,296 (24.4%) | |
| 2005–2009 | 201,623 (24.8%) | |
| 2010–2015 | 255,653 (31.5%) | |
| Age at diagnosis (cont.) | Mean (SD) | 58.0 (11.5) |
| Median (IQR) [range] | 58.0 (49.0–67.0) [30.0–79.0] | |
| Age at diagnosis (cat.) | 30–39 | 41,778 (5.1%) |
| 40–49 | 170,047 (20.9%) | |
| 50–59 | 226,896 (27.9%) | |
| 60–69 | 216,939 (26.7%) | |
| 70–79 | 157,191 (19.3%) | |
| Race | White | 652,024 (80.2%) |
| Black | 82,785 (10.2%) | |
| Asian | 56,480 (6.9%) | |
| Other/unknown | 21,562 (2.7%) | |
| Laterality | Left | 413,560 (50.9%) |
| Right | 399,291 (49.1%) | |
| Behaviour | DCIS | 153,212 (18.8%) |
| Invasive | 659,639 (81.2%) | |
| Stage | 0 | 153,212 (18.8%) |
| I | 343,074 (42.2%) | |
| II | 237,536 (29.2%) | |
| III | 79,029 (9.7%) | |
| Grade | Well differentiated (grade I) | 149,032 (18.3%) |
| Moderately differentiated (grade II) | 308,660 (38.0%) | |
| Poorly differentiated (grade III/IV) | 272,326 (33.5%) | |
| Unknown | 82,833 (10.2%) | |
| Tumour size | <1 cm | 175,553 (21.6%) |
| 1–1.9 cm | 280,525 (34.5%) | |
| 2–2.9 cm | 150,564 (18.5%) | |
| 3–4.9 cm | 95,999 (11.8%) | |
| 5–9.9 cm | 43,519 (5.4%) | |
| 10–15 cm | 4486 (0.6%) | |
| Unknown | 62,205 (7.7%) | |
| Nodal status | N0 | 605,026 (74.4%) |
| N1 | 145,237 (17.9%) | |
| N2 | 40,371 (5.0%) | |
| N3 | 22,217 (2.7%) | |
| ER status | Negative | 135,781 (16.7%) |
| Positive | 565,634 (69.6%) | |
| Unknown | 111,436 (13.7%) | |
| PR status | Negative | 202,845 (25.0%) |
| Positive | 482,909 (59.4%) | |
| Unknown | 127,097 (15.6%) | |
| Surgery | Lumpectomy | 450,700 (55.4%) |
| Mastectomy | 242,179 (29.8%) | |
| Unknown (prior to 1998) | 118,087 (14.5%) | |
| Unknown | 1885 (0.2%) | |
| Radiotherapy | No | 354,432 (43.6%) |
| Yes | 440,970 (54.2%) | |
| Unknown | 17,449 (2.1%) | |
| Chemotherapy | No/unknown | 535,867 (65.9%) |
| Yes | 276,984 (34.1%) | |
| Contralateral invasive breast cancer (outcome) | No | 786,893 (96.8%) |
| Yes | 25,958 (3.2%) | |
| Time from diagnosis to contralateral invasive breast cancer (years) | Mean (SD) | 7.1 (5.1) |
| Median (IQR) [range] | 6.2 (2.8–10.3) [0.1–25.0] | |
| Contralateral in situ breast cancer | No | 803,682 (98.9%) |
| Yes | 9169 (1.1%) | |
| New primary (non-breast) cancer | No | 754,716 (92.8%) |
| Yes | 58,135 (7.2%) | |
| Follow-up time (years) | Mean (SD) | 8.7 (5.9) |
| Median (IQR) [range] | 7.8 (3.8–12.8) [0.1–25.0] | |
| Vital status | Alive | 628,552 (77.3%) |
| Death from breast cancer | 70,068 (8.6%) | |
| Death from other cancer | 28,031 (3.4%) | |
| Death from heart disease | 35,190 (4.3%) | |
| Death from other disease | 46,496 (5.7%) | |
| Death from unknown cause | 4514 (0.6%) |