Table 1 Baseline characteristics of women diagnosed with stage I–III, operable breast cancer in Denmark from 1996 to 2009, according to thyroid status at the time of breast cancer diagnosis
Characteristics | Prevalent hypothyroidism | Incident hypothyroidism | ||||||
|---|---|---|---|---|---|---|---|---|
Thyroid status | Follow-up time1 | Thyroid status | Follow-up time1 | |||||
Normal (n = 34,191) | Hypothyroidism (n = 1272) | Normal | Hypothyroidism | Normal (n = 33,332) | Hypothyroidism (n = 859) | Normal | Hypothyroidism | |
Calendar year of diagnosis, n (%) | ||||||||
1996–1999 | 8059 (24) | 199 (16) | 47,917 | 1166 | 7888 (24) | 171 (20) | 47,339 | 679 |
2000–2004 | 11,522 (34) | 413 (32) | 76,332 | 2562 | 11,226 (34) | 296 (34) | 75,204 | 1127 |
2005–2009 | 14,610 (43) | 660 (52) | 81,280 | 3383 | 14,218 (43) | 392 (46) | 80,004 | 1276 |
Age at diagnosis, n (%) | ||||||||
35–40 years | 1172 (3) | 11 (1) | 7366 | 62 | 1147 (3) | 25 (3) | 7277 | 89 |
40–49 years | 6134 (18) | 115 (9) | 40,077 | 708 | 5961 (18) | 176 (20) | 39,441 | 637 |
50–59 years | 10,798 (32) | 346 (27) | 68,364 | 2089 | 10,511 (32) | 287 (33) | 67,281 | 1084 |
60–69 years | 11,020 (32) | 494 (39) | 64,885 | 2901 | 10,759 (32) | 261 (30) | 63,951 | 934 |
70–79 years | 4434 (13) | 263 (21) | 22,540 | 1208 | 4333 (13) | 101 (12) | 22,226 | 318 |
≥ 80 years | 633 (2) | 43 (3) | 2296 | 144 | 621 (2) | 12 (1) | 2271 | 24 |
Menopausal status at diagnosis, n (%) | ||||||||
Premenopausal | 9378 (27) | ≤ 1952 (−) | 61,404 | 1158 | 9118 (27) | ≤ 2652 (−) | 60,452 | 952 |
Postmenopausal | 24,774 (72) | 1083 (85) | 143,944 | 5937 | 24,176 (73) | 598 (70) | 141,816 | 2128 |
Unknown | 39 (0) | ≤ 52 (−) | 181 | 17 | 38 (0) | ≤ 52 (−) | 180 | 2 |
Modified comorbidity status, n (%)3 | ||||||||
None | 28,809 (84) | 957 (75) | 177,395 | 5510 | 28,093 (84) | 716 (84) | 174,781 | 2614 |
Low | 4587 (13) | 258 (20) | 24,591 | 1356 | 4466 (13) | 121 (14) | 24,182 | 409 |
High | 795 (2) | 57 (4) | 3542 | 245 | 773 (2) | 22 (3) | 3484 | 58 |
Tumour size, n (%) | ||||||||
≤ 20 mm | 20,756 (61) | ≤ 7752 (−) | 128,360 | 4479 | 20,248 (61) | ≤ 5152 (−) | 126,463 | 1896 |
21–50 mm | 12,202 (36) | 480 (38) | 71,284 | 2497 | 11,873 (36) | 329 (38) | 70,186 | 1098 |
≥ 51 mm | 1045 (3) | 23 (2) | 4878 | 113 | 1026 (3) | 19 (2) | 4795 | 83 |
Unknown | 188 (1) | ≤ 52 (−) | 1007 | 22 | 185 (1) | ≤ 52 (−) | 1003 | 4 |
Lymph node status, n (%) | ||||||||
N0 | 18,396 (54) | 724 (57) | 111,451 | 4040 | 17,986 (54) | 410 (48) | 109,988 | 1463 |
N1–3 | 10,391 (30) | 353 (28) | 66,956 | 2145 | 10,090 (30) | 301 (35) | 65,833 | 1123 |
N4+ | 5404 (16) | 195 (15) | 27,121 | 927 | 5256 (16) | 148 (17) | 26,625 | 496 |
UICC stage, n (%) | ||||||||
I | 13,433 (39) | 519 (41) | 81,013 | 2939 | 13,139 (39) | 294 (34) | 79,950 | 1063 |
II | 15,067 (44) | 551 (43) | 95,812 | 3206 | 14,654 (44) | 413 (48) | 94,303 | 1509 |
III | 5691 (17) | 202 (16) | 28,704 | 967 | 5539 (17) | 152 (18) | 28,194 | 510 |
Histological grade, n (%)4 | ||||||||
Low | 9740 (28) | 364 (29) | 59,627 | 2029 | 9500 (29) | 240 (28) | 58,749 | 878 |
Moderate | 12,742 (37) | 507 (40) | 78,631 | 2918 | 12,397 (37) | 345 (40) | 77,351 | 1280 |
High | 6608 (19) | 226 (18) | 37,186 | 1170 | 6446 (19) | 162 (19) | 36,641 | 545 |
Unknown | 5101 (15) | 175 (14) | 30,085 | 995 | 4989 (15) | 112 (13) | 29,705 | 379 |
ER status, n (%) | ||||||||
ER negative (0–9%) | 6376 (19) | 224 (18) | 35,446 | 1111 | 6198 (19) | 178 (21) | 34,822 | 624 |
ER positive (≥ 10%) | 26,954 (79) | 1031 (81) | 164,836 | 5894 | 26,294 (79) | 660 (77) | 162,448 | 2388 |
Unknown | 861 (3) | 17 (1) | 5247 | 106 | 840 (3) | 21 (3) | 5176 | 70 |
HER-2 status, n (%)5 | ||||||||
Negative | 11,551 (34) | 474 (37) | 63,723 | 2370 | 11,245 (34) | 306 (36) | 62,732 | 992 |
Positive | 2489 (7) | 114 (9) | 13,508 | 599 | 2426 (7) | 63 (7) | 13,317 | 191 |
Unknown | 20,151 (59) | 684 (54) | 128,298 | 4143 | 19,661 (59) | 490 (57) | 126,398 | 1900 |
Endocrine therapy and ER status, n (%) | ||||||||
ET−/ER− | 7010 (21) | 231 (18) | 39,283 | 1154 | 6819 (20) | 191 (22) | 38,615 | 667 |
ET+/ER+ | 17,592 (51) | 679 (53) | 113,800 | 4123 | 17,109 (51) | 483 (56) | 112,074 | 1725 |
ET−/ER+ | 9362 (27) | 352 (28) | 51,037 | 1771 | 9185 (28) | 177 (21) | 50,374 | 663 |
ET+/ER− | 227 (1) | 10 (1) | 1410 | 64 | 219 (1) | 8 (1) | 1384 | 26 |
Type of primary surgery, n (%) | ||||||||
Mastectomy without radiotherapy | 11,337 (33) | 454 (36) | 65,458 | 2379 | 11,101 (33) | 236 (27) | 64,585 | 873 |
Mastectomy with radiotherapy | 6897 (20) | 187 (15) | 41,418 | 1045 | 6692 (20) | 205 (24) | 40,708 | 710 |
Lumpectomy with radiotherapy | 15,957 (47) | 631 (50) | 98,653 | 3688 | 15,539 (47) | 418 (49) | 97,154 | 1499 |
Systemic therapy, n (%) | ||||||||
No | 2091 (6) | 73 (6) | 10,265 | 269 | 2046 (6) | 45 (5) | 10,089 | 176 |
Yes | 32,100 (94) | 1199 (94) | 195,265 | 6843 | 31,286 (94) | 814 (95) | 192,358 | 2906 |
Chemotherapy, n (%) | ||||||||
No | 23,233 (68) | 965 (76) | 135,848 | 5277 | 22,713 (68) | 520 (61) | 133,933 | 1915 |
Yes | 10,958 (32) | 307 (24) | 69,681 | 1835 | 10,619 (32) | 339 (39) | 68,514 | 1167 |
Endocrine therapy, n (%) | ||||||||
No | 16,117 (47) | 577 (45) | 88,710 | 2885 | 15,754 (47) | 363 (42) | 87,396 | 1314 |
Yes | 18,074 (53) | 695 (55) | 116,819 | 4227 | 17,578 (53) | 496 (58) | 115,051 | 1768 |
Radiotherapy, n (%) | ||||||||
No | 11,337 (33) | 454 (36) | 65,458 | 2379 | 11,101 (33) | 236 (27) | 64,585 | 873 |
Yes | 22,854 (67) | 818 (64) | 140,071 | 4733 | 22,231 (67) | 623 (73) | 137,862 | 2209 |
Co-medication at baseline, n (%) | ||||||||
Simvastatin user | 1791 (5) | 135 (11) | 9321 | 716 | 1753 (5) | 38 (4) | 9217 | 103 |
Aspirin user | 447 (1) | 23 (2) | 2540 | 117 | 439 (1) | 8 (1) | 2503 | 36 |