Table 1.
Characteristics of 11562 Bilateral Breast Cancer Patients, SEER 1998-2011
| Characteristics | SBC cohort (n=4403) | MBC cohort (n=7159) |
|
|---|---|---|---|
| First cancer | Second cancer | ||
| Year of diagnosis | 1998-2005 | 1998-2005 | 1998-2011 |
| Age at diagnosis, mean±SD | 63.1±13.7 | 59.4±12.9 | 64.6±13.0 |
| Months between two cancers, median (IQR) range | 0 (0-1) 0-6 |
60 (33-87) 7-164 |
|
| Race/ethnicity, n (%) | |||
| White | 3571 (82) | 5390 (76) | |
| Black | 317 (7) | 751 (11) | |
| Asian | 233 (5) | 478 (7) | |
| Latino | 257 (6) | 515 (7) | |
| Others/unknown | 25 | 25 | |
| Marital status, n (%) | |||
| Single | 563 (13) | 834 (12) | |
| Married | 2300 (54) | 3800 (56) | |
| Divorced/ separated | 498 (12) | 829 (12) | |
| Widowed | 891 (21) | 1326 (20) | |
| Unknown | 151 | 370 | |
| Estrogen receptor, n (%) | |||
| +/+ | 3611 (82) | 4137 (58) | |
| −/− | 370 (8) | 934 (13) | |
| Discordant | 422 (10) | ||
| +/− | 1080 (15) | ||
| −/+ | 1008 (14) | ||
| Progesterone receptor, n (%) | |||
| +/+ | 2930 (67) | 2835 (40) | |
| −/− | 657 (15) | 1441 (20) | |
| Discordant | 816 (19) | ||
| +/− | 1741 (24) | ||
| −/+ | 1142 (16) | ||
| Histology of two tumors combination, n (%) | |||
| Ductal/ductal | 2769 (63) | ||
| Ductal/lobular | 612 (14) | ||
| Ductal/other | 615 (14) | ||
| Lobular/lobular | 202 (5) | ||
| Lobular/other | 72 (2) | ||
| Other/other | 133 (3) | ||
| Histology, n (%) | |||
| Ductal | 5819 (81) | 5759 (80) | |
| Lobular | 515 (7) | 648 (9) | |
| Other | 825 (12) | 752 (11) | |
| Grade, n (%) | |||
| Well differentiated | 599 (14) | 1331 (20) | 1318 (20) |
| Moderately differentiated | 1978 (47) | 2663 (41) | 2607 (39) |
| Poorly or non-differentiated | 1632 (39) | 2577 (39) | 2676 (41) |
| Unknown | 194 | 588 | 558 |
| AJCC stage, n (%) | |||
| 0 | 148 (3) | 580 (8) | 1220 (18) |
| 1 | 1434 (33) | 3467 (49) | 3458 (50) |
| 2A | 1208 (28) | 1552 (22) | 1143 (17) |
| 2B | 660 (15) | 649 (9) | 399 (6) |
| 3A | 466 (11) | 410 (6) | 306 (4) |
| 3B | 182 (4) | 149 (2) | 148 (2) |
| 3 | 254 (6) | 206 (3) | 213 (3) |
| Unknown | 51 | 146 | 272 |
| Tumor size in cm, median (IQR) | 2.1 (1.4-3.3) | 1.5 (1.0-2.5) | 1.3 (0.8-2.1) |
| No. of positive nodes | |||
| 0 | 2373 (55) | 5090 (73) | 5378 (79) |
| 1-3 | 1217 (28) | 1291 (18) | 902 (13) |
| 4-9 | 438 (10) | 389 (6) | 313 (5) |
| ≥ 10 | 265 (6) | 226 (3) | 214 (3) |
| Unknown | 110 | 163 | 352 |
| Surgery | |||
| No | 90 (2) | 83 (1) | 296 (4) |
| Lumpectomy | 1283 (29) | 4300 (60) | 3297 (46) |
| Mastectomy | 2425 (55) | 2743 (38) | 2993 (42) |
| Bilateral mastectomy | 605 (14) | 33 (0.5) | 573 (8) |
| Radiotherapy | |||
| No | 2680 (63) | 2849 (41) | 4398 (64) |
| Yes | 1593 (37) | 4046 (59) | 2499 (36) |
| Unknown | 130 | 264 | 262 |
Abbreviations: AJCC, American Joint Committee on Cancer; IQR, interquartile range; MBC, metachronous breast cancer; SBC, synchronous breast cancer; SD, standard deviation