Patient, breast cancer and treatment characteristics of study population
| Characteristic | No. (%) of patients;* receipt of imaging test | p value | No. (%) of patients | |
|---|---|---|---|---|
| Routine BS, CT, MRI or PET n = 2887 | No routine BS, CT, MRI or PET n = 7255 | Entire cohort n = 10 142 | ||
| Age group, yr | < 0.001 | |||
| ≤ 40 | 234 (8.1) | 273 (3.8) | 507 (5.0) | |
| 41–50 | 550 (19.1) | 1107 (15.3) | 1657 (16.3) | |
| 51–60 | 773 (26.8) | 1915 (26.4) | 2688 (26.5) | |
| 61–70 | 737 (25.5 | 1982 (27.3) | 2719 (26.8) | |
| > 70 | 593 (20.5) | 1978 (27.3) | 2571 (25.4) | |
| CCI score | 0.476 | |||
| 0 | 2420 (84.0) | 5971 (83.1) | 8391 (83.3) | |
| 1 | 342 (11.9) | 915 (12.7) | 1257 (12.5) | |
| ≥ 2 | 118 (4.1) | 302 (4.2) | 420 (4.2) | |
| Unknown, no. | 7 | 67 | 74 | |
| Year of diagnosis | 0.008 | |||
| 2011 | 567 (19.6) | 1317 (18.2) | 1884 (18.6) | |
| 2012 | 554 (19.2) | 1370 (18.9) | 1924 (19.0) | |
| 2013 | 529 (18.3) | 1452 (20.0) | 1981 (19.5) | |
| 2014 | 654 (22.7) | 1497 (20.6) | 2151 (21.2) | |
| 2015 | 583 (20.2) | 1619 (22.3) | 2202 (21.7) | |
| Zone at diagnosis† | < 0.001 | |||
| Z1 | 603 (20.9) | 2740 (37.8) | 3343 (33.0) | |
| Z2 | 1192 (41.3) | 2676 (36.9) | 3868 (38.1) | |
| Z3 | 451 (15.6) | 342 (4.7) | 793 (7.8) | |
| Z4 | 403 (14.0) | 862 (11.9) | 1265 (12.5) | |
| Z5 | 238 (8.2) | 635 (8.8) | 873 (8.6) | |
| Setting of diagnosis | < 0.001 | |||
| Urban | 1795 (62.2) | 5416 (74.7) | 7211 (71.1) | |
| Rural | 1092 (37.8) | 1839 (25.3) | 2931 (28.9) | |
| Preoperative chest radiograph | < 0.001 | |||
| Yes | 988 (34.2) | 1926 (26.5) | 2914 (28.7) | |
| No | 1899 (65.8) | 5329 (73.5) | 7228 (71.3) | |
| Surgery | < 0.001 | |||
| Mastectomy | 1612 (55.9) | 2869 (39.6) | 4481 (44.2) | |
| BCS | 1274 (44.1) | 4382 (60.4) | 5656 (55.8) | |
| Unknown, no. | 1 | 4 | 5 | |
| Stage | < 0.001 | |||
| 0 (DCIS) | 52 (1.8) | 1345 (18.5) | 1397 (13.8) | |
| I | 759 (26.3) | 3949 (54.4) | 4708 (46.4) | |
| II | 2076 (71.9) | 1961 (27.0) | 4037 (39.8) | |
| Lymph dode | < 0.001 | |||
| Positive | 1310 (48.3) | 598 (8.6) | 1908 (19.8) | |
| Negative | 1401 (51.7) | 6351 (91.4) | 7752 (80.2) | |
| Unknown, no. | 176 | 306 | 482 | |
| Grade | < 0.001 | |||
| I | 347 (12.2) | 1459 (21.2) | 1806 (18.6) | |
| 2 | 1190 (41.8) | 2921 (42.5) | 4111 (42.3) | |
| 3 | 1307 (46.0) | 2490 (36.2) | 3797 (39.1) | |
| Unknown, no. | 43 | 385 | 428 | |
| LVI | < 0.001 | |||
| Present | 1002 (36.5) | 109615.4) | 2098 (21.3) | |
| Absent | 1745 (63.5) | 6002 (84.6) | 7747 (78.7) | |
| Unknown, no. | 140 | 157 | 297 | |
| ER status | < 0.001 | |||
| Positive | 2443 (85.3) | 5834 (88.8) | 8277 (87.7) | |
| Negative | 422 (14.7) | 736 (11.2) | 1158 (12.3) | |
| Unknown, no. | 22 | 685 | 707 | |
| PR status | < 0.001 | |||
| Positive | 2127 (74.2) | 5113 (77.9) | 7240 (76.8) | |
| Negative | 738 (25.8) | 1449 (22.1) | 2187 (23.2) | |
| Unknown, no. | 22 | 693 | 715 | |
| HER2 status | < 0.001 | |||
| Positive | 459 (16.5) | 621 (10.7) | 1080 (12.6) | |
| Negative | 2319 (83.5) | 5159 (89.3) | 7478 (87.4) | |
| Unknown, no. | 109 | 1475 | 1584 | |
| TNBC | 0.006 | |||
| Yes | 262 (9.4) | 444 (7.7) | 706 (8.3) | |
| No | 2516 (90.6) | 5331 (92.3) | 7847 (91.7) | |
| Unknown, no. | 109 | 1480 | 1589 | |
| Chemotherapy | < 0.001 | |||
| Yes | 1685 (58.4) | 1635 (22.5) | 3320 (32.7) | |
| No | 1202 (41.6) | 5620 (77.5) | 6822 (67.3) | |
| Radiotherapy | < 0.001 | |||
| Yes | 1723 (59.7) | 3980 (54.9) | 5703 (56.2) | |
| No | 1164 (40.3) | 3275 (45.1) | 4439 (43.8) | |
BCS = breast-conserving surgery; BS = bone scanning; CCI = Charlson Comorbidity Index; CT = computed tomography; DCIS = ductal carcinoma in situ; ER = estrogen receptor; HER2 = human epidermal growth factor receptor 2; LVI = lymphovascular invasion; MRI = magnetic resonance imaging; PET = positron emission tomography; PR = progesterone receptor; TNBC = triple-negative breast cancer.
↵* Unless indicated otherwise.
↵† Alberta Health Services is organized into 5 geographic zones.