Table 1 Demographic and clinicopathological characteristics of study population
2010–2015 dataset (n = 19,791) | 2004–2009 dataset (n = 9346) | |||||
|---|---|---|---|---|---|---|
RS 18–25 [n = 15,731; No. (%)] | RS 26–30 [n = 4060; No. (%)] | P | RS 18–25 [n = 7401; No. (%)] | RS 26–30 [n = 1945; No. (%)] | P | |
Year of diagnosis | ||||||
2004–2005 | – | – | 567 (7.7) | 155 (8.0) | 0.421 | |
2006–2007 | – | – | 2522 (34.1) | 689 (35.4) | ||
2008–2009 | – | – | 4312 (58.3) | 1101 (56.6) | ||
2010–2011 | 4748 (30.2) | 1243 (30.6) | 0.797 | – | – | |
2012–2013 | 5229 (33.2) | 1329 (32.7) | – | – | ||
2014–2015 | 5754 (36.6) | 1488 (36.7) | – | – | ||
Age at diagnosis (years) | ||||||
≤ 50 | 3836 (24.4) | 923 (22.7) | 0.025 | 2340 (31.6) | 539 (27.7) | 0.003 |
51–60 | 4924 (31.3) | 1239 (30.5) | 2456 (33.2) | 654 (33.6) | ||
61–70 | 4990 (31.7) | 1378 (33.9) | 1971 (26.6) | 557 (28.6) | ||
> 70 | 1981 (12.6) | 520 (12.8) | 634 (8.6) | 195 (10.0) | ||
Race/ethnicity | ||||||
White | 12,946 (82.3) | 3263 (80.4) | 0.018 | 6299 (85.1) | 1662 (85.5) | 0.737 |
Black | 1296 (8.2) | 391 (9.6) | 506 (6.8) | 139 (7.2) | ||
Other* | 1405 (8.9) | 386 (9.5) | 561 (7.6) | 137 (7.0) | ||
Missing | 84 (0.5) | 20 (0.5) | 35 (0.5) | 7 (0.4) | ||
History of cancer | ||||||
No | 13,960 (88.7) | 3551 (87.5) | 0.023 | 6654 (89.9) | 1764 (90.7) | 0.302 |
Yes | 1771 (11.3) | 509 (12.5) | 747 (10.1) | 181 (9.3) | ||
Marital status | ||||||
Married | 9819 (62.4) | 2473 (60.9) | 0.004 | 4924 (66.5) | 1259 (64.7) | 0.215 |
Single | 2105 (13.4) | 630 (15.5) | 885 (12.0) | 255 (13.1) | ||
Other† | 3078 (19.6) | 786 (19.4) | 1333 (18.0) | 372 (19.1) | ||
Missing | 729 (4.6) | 171 (4.2) | 259 (3.5) | 59 (3.0) | ||
Histologic type | ||||||
Ductal | 11,490 (73.0) | 3226 (79.5) | < 0.001 | 5446 (73.6) | 1556 (80.0) | < 0.001 |
Lobular | 2251 (14.3) | 391 (9.6) | 897 (12.1) | 161 (8.3) | ||
Mixed ductal-lobular | 1818 (11.6) | 394 (9.7) | 960 (13.0) | 202 (10.4) | ||
Other | 172 (1.1) | 49 (1.2) | 98 (1.3) | 26 (1.3) | ||
Tumor stage | ||||||
T1b | 3535 (22.5) | 801 (19.7) | < 0.001 | 1789 (24.2) | 409 (21.0) | < 0.001 |
T1c | 8271 (52.6) | 2112 (52.0) | 4217 (57.0) | 1070 (55.0) | ||
T2 | 3698 (23.5) | 1091 (26.9) | 1339 (18.1) | 446 (22.9) | ||
T3 | 227 (1.4) | 56 (1.4) | 56 (0.8) | 20 (1.0) | ||
Grade | ||||||
I | 3774 (24.0) | 486 (12.0) | < 0.001 | 1795 (24.3) | 251 (12.9) | < 0.001 |
II | 8990 (57.2) | 2087 (51.4) | 4145 (56.0) | 1007 (51.8) | ||
III | 2644 (16.8) | 1434 (35.3) | 1233 (16.7) | 636 (32.7) | ||
Missing | 323 (2.1) | 53 (1.3) | 228 (3.1) | 51 (2.6) | ||
ER/PR status | ||||||
+/+ | 13,842 (88.0) | 3164 (77.9) | < 0.001 | 6389 (86.3) | 1459 (75.0) | < 0.001 |
+/− | 1872 (11.9) | 885 (21.8) | 993 (13.4) | 478 (24.6) | ||
−/+ | 17 (0.1) | 11 (0.3) | 19 (0.3) | 8 (0.4) | ||
Type of surgery | ||||||
Breast-conservation surgery | 10,806 (68.7) | 2747 (67.7) | 0.207 | 5199 (70.3) | 1326 (68.2) | 0.076 |
Mastectomy | 4925 (31.3) | 1313 (32.3) | 2202 (29.8) | 619 (31.8) | ||
Radiation therapy | ||||||
No or unknown | 6268 (39.8) | 1834 (45.2) | < 0.001 | 3038 (41.1) | 853 (43.9) | 0.025 |
Yes | 9463 (60.2) | 2226 (54.8) | 4363 (59.0) | 1092 (56.1) | ||
Chemotherapy | ||||||
No or unknown | 11,832 (75.2) | 1807 (44.5) | < 0.001 | 5044 (68.2) | 865 (44.5) | < 0.001 |
Yes | 3899 (24.8) | 2253 (55.5) | 2357 (31.9) | 1080 (55.5) | ||