Table 1.
Baseline characteristics of patients between 2004 and 2012 in the SEER database (n = 8524).
| Variables | n | Low (%) | Intermediate (%) | High (%) | P |
|---|---|---|---|---|---|
| Age (years) | |||||
| 65-69 | 4631 | 1020 (51.3) | 2816 (55.7) | 795 (53.8) | 0.025 |
| 70-74 | 2441 | 604 (30.4) | 1405 (27.8) | 432 (29.2) | |
| >74 | 1452 | 363 (18.3) | 838 (16.6) | 251 (17.0) | |
| Race/ethnicity | |||||
| Non-Hispanic White | 6836 | 1576 (79.3) | 4106 (81.2) | 1154 (78.1) | 0.004 |
| Non-Hispanic Black | 601 | 153 (7.7) | 326 (6.4) | 122 (8.3) | |
| Hispanic (all) | 553 | 113 (5.7) | 342 (6.8) | 98 (6.5) | |
| Other | 534 | 145 (7.3) | 285 (5.6) | 104 (6.3) | |
| Grade | |||||
| Well differentiated | 2097 | 638 (32.1) | 1337 (26.4) | 122 (8.3) | <0.001 |
| Moderately differentiated | 4737 | 1168 (58.8) | 2948 (58.3) | 621 (42.0) | |
| Poorly/undifferentiated | 1690 | 181 (9.1) | 774 (15.3) | 735 (49.7) | |
| Tumor stage | |||||
| T1 | 6477 | 1510 (76.0) | 3956 (78.2) | 1011 (68.4) | <0.001 |
| T2 | 2047 | 477 (24.0) | 1103 (21.8) | 467 (31.6) | |
| PR status | |||||
| Negative | 1056 | 41 (2.1) | 540 (10.7) | 475 (32.1) | <0.001 |
| Positive | 7468 | 1946 (97.9) | 4519 (89.3) | 1003 (67.9) | |
| Surgical procedure | |||||
| Breast-conserving surgery | 6387 | 1460 (73.5) | 3867 (76.4) | 1060 (71.7) | <0.001 |
| Mastectomy | 2137 | 527 (26.5) | 1192 (23.6) | 418 (28.3) | |
| Radiotherapy | |||||
| No | 3016 | 721 (36.3) | 1708 (33.8) | 587 (39.7) | <0.001 |
| Yes | 5508 | 1266 (63.7) | 3351 (66.2) | 891 (60.3) | |
| Chemotherapy | |||||
| No | 7295 | 1948 (98.0) | 4625 (91.4) | 722 (48.8) | <0.001 |
| Yes | 1229 | 39 (2.0) | 434 (8.6) | 756 (51.2) | |
PR, progesterone receptor; T, tumor.