Table 1.
Description of study sociodemographic and clinical variablesa.
| Variable | Total sample N = 24,532 | Low nSES N = 8060 (32.9) | Middle nSES N = 8293 (33.8) | High nSES N = 8179 (33.3) | P-value |
|---|---|---|---|---|---|
| Age (years, continuous) Mean (SD) | 62.21 (13.97) | 61.20 (13.90) | 62.59 (13.90) | 62.80 (14.07) | <0.001 |
| Age (years) | |||||
| ≤40 | 1730 (7.1) | 619 (7.7) | 562 (6.8) | 549 (6.7) | <0.001 |
| 41–64 | 12,071 (49.2) | 4174 (51.8) | 4012 (48.4) | 3885 (47.5) | |
| ≥65 | 10,731 (43.7) | 3267 (40.5) | 3719 (44.8) | 3745 (45.8) | |
| Race | |||||
| White | 18,481 (75.3) | 5115 (63.4) | 6556 (79.1) | 6810 (83.3) | <0.001 |
| Black | 4109 (16.8) | 2554 (31.7) | 1065 (12.8) | 490 (6.0) | |
| Other | 1841 (7.5) | 360 (4.5) | 646 (7.8) | 835 (10.2) | |
| Unknown | 101 (0.4) | 31 (0.4) | 26 (0.3) | 44 (0.5) | |
| Hispanic | |||||
| No | 21,823 (89.0) | 6875 (85.3) | 7351 (88.6) | 7597 (92.9) | <0.001 |
| Yes | 2709 (11.0) | 1185 (14.7) | 942 (11.4) | 582 (7.1) | |
| Marital Status | |||||
| Married/Partnered | 10,392 (42.4) | 2788 (34.6) | 3609 (43.5) | 3995 (48.8) | <0.001 |
| Separated/divorced | 3227 (13.2) | 1224 (15.2) | 1088 (13.1) | 915 (11.2) | |
| Single | 5158 (21.0) | 2130 (26.4) | 1627 (19.6) | 1401 (17.1) | |
| Unmarried/Domestic Partner | 70 (0.3) | 18 (0.2) | 21 (0.3) | 31 (0.4) | |
| Widowed | 4256 (17.3) | 1410 (17.5) | 1454 (17.5) | 1392 (17.0) | |
| Unknown | 1429 (5.8) | 490 (6.1) | 494 (6.0) | 445 (5.5) | |
| Year of Diagnosis | |||||
| 2010 | 3329 (13.6) | 1051 (13.0) | 1134 (13.7) | 1144 (14.0) | 0.14 |
| 2011 | 3374 (13.8) | 1172 (14.6) | 1087 (13.1) | 1115 (13.6) | |
| 2012 | 3422 (13.9) | 1148 (14.2) | 1153 (13.9) | 1121 (13.7) | |
| 2013 | 3614 (14.7) | 1235 (15.3) | 1217 (14.7) | 1162 (14.2) | |
| 2014 | 3608 (14.7) | 1151 (14.3) | 1234 (14.9) | 1223 (15.0) | |
| 2015 | 3560 (14.5) | 1153 (14.3) | 1219 (14.7) | 1188 (14.5) | |
| 2016 | 3625 (14.8) | 1150 (14.3) | 1249 (15.0) | 1226 (15.0) | |
| Region | |||||
| East | 10,188 (41.5) | 4040 (50.1) | 3114 (37.5) | 3034 (37.1) | <0.001 |
| Northern Plains | 2369 (9.7) | 914 (11.3) | 1026 (12.4) | 429 (5.2) | |
| Pacific Cost | 10,992 (44.8) | 2796 (34.7) | 3723 (44.9) | 4473 (54.7) | |
| Southwest | 983 (4.0) | 310 (3.8) | 430 (5.2) | 243 (3.0) | |
| Insurance | |||||
| Uninsured | 960 (3.9) | 438 (5.4) | 300 (3.6) | 222 (2.7) | <0.001 |
| Medicaid | 4686 (19.1) | 2378 (29.5) | 1443 (17.4) | 865 (10.6) | |
| Insured | 18,217 (74.3) | 5024 (62.4) | 6311 (76.1) | 6882 (84.1) | |
| Unknown | 669 (2.7) | 220 (2.7) | 239 (2.9) | 210 (2.6) | |
| Tumor size | |||||
| ≤2 cm | 592 (3.1) | 152 (2.4) | 217 (3.4) | 223 (3.5) | <0.001 |
| >2 cm–5cm | 11,173 (58.6) | 3598 (57.8) | 3741 (58.1) | 3834 (60.0) | |
| ≥5 cm | 7289 (38.3) | 2479 (39.8) | 2481 (38.5) | 2329 (36.5) | |
| Grade | |||||
| Well-differentiated | 1505 (6.1) | 447 (5.5) | 535 (6.5) | 523 (6.4) | <0.001 |
| Moderately differentiated | 7527 (30.7) | 2342 (29.1) | 2599 (31.3) | 2586 (31.6) | |
| Poorly differentiated | 8876 (36.2) | 3105 (38.5) | 2957 (35.7) | 2814 (34.4) | |
| Undifferentiated/anaplastic | 155 (0.6) | 51 (0.6) | 61 (0.7) | 43 (0.5) | |
| Unknown | 6469 (26.4) | 2115 (26.3) | 2141 (25.8) | 2213 (27.1) | |
| Breast Cancer Subtype | |||||
| Luminal A | 12,377 (50.4) | 3800 (47.1) | 4243 (51.2) | 4334 (53.0) | <0.001 |
| Luminal B | 3392 (13.8) | 1105 (13.7) | 1115 (13.4) | 1172 (14.3) | |
| HER 2 enriched | 1828 (7.5) | 626 (7.8) | 605 (7.3) | 597 (7.3) | |
| Triple-Negative | 2939 (12.0) | 1125 (14.0) | 1007 (12.1) | 807 (9.9) | |
| Unknown | 3996 (16.3) | 1404 (17.4) | 1323 (16.0) | 1269 (15.5) | |
| Histology | |||||
| Ductal | 15,698 (64.0) | 5320 (66.0) | 5355 (64.6) | 5023 (61.4) | <0.001 |
| Lobular | 2598 (10.6) | 697 (8.7) | 879 (10.6) | 1022 (12.5) | |
| Mixed (ductal and lobular) | 989 (4.0) | 270 (3.3) | 346 (4.2) | 373 (4.6) | |
| Other | 5247 (21.4) | 1773 (22.0) | 1713 (20.6) | 1761 (21.5) | |
| Metastasis | |||||
| Bone only | 8222 (33.5) | 2560 (31.8) | 2793 (33.7) | 2869 (35.1) | <0.001 |
| Liver only | 1501 (6.1) | 485 (6.0) | 468 (5.6) | 548 (6.7) | |
| Lung only | 2311 (9.4) | 806 (10.0) | 798 (9.6) | 707 (8.6) | |
| Brain only | 308 (1.3) | 126 (1.6) | 104 (1.3) | 78 (1.0) | |
| ≥2 metastasis | 7282 (29.7) | 2450 (30.4) | 2465 (29.7) | 2367 (28.9) | |
| Other | 4553 (18.6) | 1520 (18.8) | 1546 (18.7) | 1487 (18.2) | |
| Unknown | 355 (1.4) | 113 (1.4) | 119 (1.4) | 123 (1.5) | |
| Surgery | |||||
| No | 17,332 (71.3) | 5567 (69.9) | 5888 (71.5) | 5877 (72.4) | 0.001 |
| Yes | 6990 (28.7) | 2402 (30.1) | 2348 (28.5) | 2240 (27.6) | |
| Radiation therapy | |||||
| No/unknown | 17.145 (69.9) | 5719 (71.0) | 5710 (68.9) | 5716 (69.9) | 0.014 |
| yes | 7387 (30.1) | 2341 (29.0) | 2583 (31.1) | 2463 (30.1) | |
| Chemotherapy | |||||
| No/unknown | 11,707 (47.7) | 3794 (47.1) | 3993 (48.1) | 3920 (47.9) | 0.35 |
| Yes | 12,825 (52.3) | 4266 (52.9) | 4300 (51.9) | 4259 (52.1) | |
| Mean survival (S.E.) months | 45.41 (0.27) | 41.02 (0.47) | 44.77 (0.47) | 50.28 (0.47) | <0.001 |
a
Datapoints reported as n (%) unless specified otherwise. Data may not add up to 100 % due to rounding.