Table 1.
Baseline characteristics of first and second breast cancers, by estrogen receptor status
| First breast cancer |
Second breast cancer |
|||
|---|---|---|---|---|
| Estrogen receptor positive | Estrogen receptor negative | Estrogen receptor positive | Estrogen receptor negative | |
| (n = 303 837) | (n = 53 367) | (n = 5606) | (n = 1123) | |
| Age of diagnosis, mean (SD), y | 59.7 (13.1) | 53.2 (11.8) | 65.0 (12.4) | 56.8 (11.4) |
| Follow-up time, mean (SD), y | 9.66 (4.21) | 9.19 (4.83) | 7.45 (3.39) | 7.30 (3.72) |
| Year of diagnosis, No. (%) | ||||
| 2000-2004 | 86 869 (28.6) | 16 896 (31.7) | 535 (9.5) | 102 (9.1) |
| 2005-2009 | 111 613 (36.7) | 20 562 (38.5) | 2049 (36.6) | 491 (43.7) |
| 2010-2013 | 105 355 (34.7) | 15 909 (29.8) | 3022 (53.9) | 530 (47.2) |
| Race and ethnicity, No. (%) | ||||
| Hispanic | 28 329 (9.3) | 6204 (11.6) | 433 (7.7) | 135 (12.0) |
| Non-Hispanic Black | 24 403 (8.0) | 9207 (17.3) | 527 (9.4) | 253 (22.5) |
| Non-Hispanic White | 224 417 (73.9) | 33 357 (62.5) | 4225 (75.4) | 652 (58.1) |
| Othera | 25 753 (8.5) | 4479 (8.4) | 419 (7.5) | 82 (7.3) |
| Missing | 935 (0.3) | 120 (0.2) | 2 (0.0) | 1 (0.1) |
| Tumor stage, No. (%) | ||||
| Local | 199 362 (65.6) | 28 799 (54.0) | 4142 (73.9) | 720 (64.1) |
| Regional | 104 475 (34.4) | 24 568 (46.0) | 1464 (26.1) | 403 (35.9) |
| Tumor grade, No. (%) | ||||
| 1 | 80 328 (26.4) | 706 (1.3) | 1575 (28.1) | 20 (1.8) |
| 2 | 147 608 (48.6) | 8233 (15.4) | 2707 (48.3) | 207 (18.4) |
| 3 | 75 901 (25.0) | 44 428 (83.2) | 1324 (23.6) | 896 (79.8) |
| Lymph node status, No. (%) | ||||
| Negative | 204 106 (67.2) | 30 813 (57.7) | 4254 (75.9) | 753 (67.1) |
| Positive | 99 731 (32.8) | 22 554 (42.3) | 1352 (24.1) | 370 (32.9) |
| Tumor size, No. (%) | ||||
| <10 mm | 63 334 (20.8) | 3738 (7.0) | 1771 (31.6) | 146 (13.0) |
| 10-19 mm | 121 908 (40.1) | 15 602 (29.2) | 2244 (40.0) | 397 (35.4) |
| 20-49 mm | 99 861 (32.9) | 27 203 (51.0) | 1332 (23.8) | 485 (43.2) |
| ≥50 mm | 18 734 (6.2) | 6824 (12.8) | 259 (4.6) | 95 (8.5) |
| Histology, No. (%) | ||||
| Ductal carcinoma | 223 668 (73.6) | 46 655 (87.4) | 3892 (69.4) | 961 (85.6) |
| Lobular carcinoma | 26 072 (8.6) | 447 (0.8) | 642 (11.5) | 25 (2.2) |
| Ductal and locular carcinoma | 25 605 (8.4) | 1006 (1.9) | 496 (8.8) | 22 (2.0) |
| Others | 28 492 (9.4) | 5259 (9.9) | 576 (10.3) | 115 (10.2) |
| Chemotherapy, No. (%) | ||||
| No/unknownb | 185 260 (61.0) | 0 (0) | 4160 (74.2) | 0 (0) |
| Yes | 118 577 (39.0) | 53 367 (100) | 1446 (25.8) | 1123 (100) |
| Radiation therapy, No. (%) | ||||
| No/unknownb | 130 914 (43.1) | 22 086 (41.4) | 3650 (65.1) | 770 (68.6) |
| Yes | 172 923 (56.9) | 31 281 (58.6) | 1956 (34.9) | 353 (31.4) |
| Predict 5-y breast cancer mortality, mean (SD) | 0.04 (0.07) | 0.22 (0.16) | 0.04 (0.06) | 0.19 (0.15) |
| Characteristics of the initial breast cancer for patients with a second breast cancer | ||||
| Time between first and second breast cancer, No. (%),y | ||||
| 1-4 | — | — | 2552 (45.5) | 531 (47.3) |
| 5-9 | — | — | 2327 (41.5) | 491 (43.7) |
| ≥10 | — | — | 727 (13.0) | 101 (9.0) |
| Age at diagnosis, mean (SD), y | — | — | 59.7 (12.5) | 51.7 (11.4) |
| Tumor stage, No. (%) | ||||
| Local | — | — | 4061 (72.4) | 746 (66.4) |
| Regional | — | — | 1423 (25.4) | 356 (31.7) |
| Distant | — | — | 53 (0.9) | 7 (0.6) |
| Missing | — | — | 69 (1.2) | 14 (1.2) |
| Tumor grade, No. (%) | ||||
| 1 | — | — | 1373 (24.5) | 104 (9.3) |
| 2 | — | — | 2274 (40.6) | 311 (27.7) |
| 3 | — | — | 1485 (26.5) | 637 (56.7) |
| Missing | — | — | 474 (8.5) | 71 (6.3) |
| Lymph node status, No. (%) | ||||
| Negative | — | — | 3784 (67.5) | 733 (65.3) |
| Positive | — | — | 1320 (23.5) | 324 (28.9) |
| Missing | — | — | 502 (9.0) | 66 (5.9) |
| Tumor size, No. (%) | ||||
| <10 mm | — | — | 1292 (23.0) | 171 (15.2) |
| 10-19 mm | — | — | 2026 (36.1) | 366 (32.6) |
| 20-49 mm | — | — | 1515 (27.0) | 425 (37.8) |
| ≥50 mm | — | — | 306 (5.5) | 81 (7.2) |
| Missing | — | — | 467 (8.3) | 80 (7.1) |
| Estrogen receptor status, No. (%) | ||||
| Positive | — | — | 4035 (72.0) | 493 (43.9) |
| Negative | — | — | 901 (16.1) | 513 (45.7) |
| Missing | — | — | 670 (12.0) | 117 (10.4) |
| Predict 5-y breast cancer mortality, mean (SD)c | — | — | 0.07 (0.10) | 0.12 (0.13) |
| Surgery, No. (%) | ||||
| No | — | — | 140 (2.5) | 24 (2.1) |
| Yes | — | — | 5466 (97.5) | 1099 (97.9) |
| Chemotherapy, No. (%) | ||||
| No/unknownb | — | — | 3662 (65.3) | 420 (37.4) |
| Yes | — | — | 1944 (34.7) | 703 (62.6) |
| Radiation therapy, No. (%) | ||||
| No/unknownb | — | — | 2496 (44.5) | 416 (37.0) |
| Yes | — | — | 3110 (55.5) | 707 (63.0) |
a
“Other” included non-Hispanic Asian and Pacific Islander, non-Hispanic American Indian, and Alaska Native.
b
No evidence of chemotherapy or radiation therapy was found in the medical records. It could be that patients did not have the treatment or patients had the treatment, but it was not recorded in medical records.
c
This was calculated at time of initial presentation of local or regional stage breast cancer treated by surgery. Data was also available on tumor grade, lymph node status, tumor size, and estrogen receptor status.