Table 3. Characteristics of patients by histology subtype in 1:1 matched, AAC versus IDC.
| AAC, n = 840 | IDC, n = 840 | Total, n = 1,680 | P-Valuea | |
|---|---|---|---|---|
| (%) | (%) | (%) | ||
| Median follow-up (months) (IQR) | 61 (31.25–94) | 60 (29–92) | 61 (30–93) | |
| Age at diagnosis (years) | ||||
| 18–49 | 159 (18.9) | 151 (18.0) | 310 (18.4) | 0.615 |
| 50–79 | 681 (81.1) | 689 (82.0) | 1,370 (81.6) | |
| Race | ||||
| White | 635 (75.6) | 613 (73.0) | 1,248 (74.3) | 0.199 |
| Black | 99 (11.8) | 124 (14.8) | 223 (13.3) | |
| Othersb | 104 (12.4) | 98 (11.7) | 202 (12.0) | |
| Unknown | 2 (0.2) | 5 (0.6) | 7 (0.4) | |
| Marital status | ||||
| Married | 496 (59.0) | 504 (60.0) | 1,000 (59.5) | 0.368 |
| Not marriedc | 321 (38.2) | 304 (36.2) | 625 (37.2) | |
| Unknown | 23 (2.70) | 32 (3.80) | 55 (3.3) | |
| Laterality | ||||
| Left | 434 (51.7) | 410 (48.8) | 844 (50.2) | 0.314 |
| Right | 406 (48.3) | 429 (51.1) | 835 (49.7) | |
| Only one side, NOS | 0 (0.0) | 1 (0.1) | 1 (0.1) | |
| Grade | ||||
| I | 59 (7.0) | 81 (9.6) | 140 (8.3) | < 0.001 |
| II | 390 (46.4) | 313 (37.3) | 703 (41.8) | |
| III + UDd | 363 (43.2) | 433 (51.5) | 796 (47.4) | |
| Unknown | 28 (3.3) | 13 (1.5) | 41 (2.4) | |
| Tumor size (cm) | ||||
| ≤ 2 | 483 (57.5) | 511 (60.8) | 994 (59.2) | 0.034 |
| > 2 and ≤ 5 | 285 (33.9) | 270 (32.1) | 555 (33.0) | |
| > 5 | 62 (7.4) | 58 (6.9) | 120 (7.1) | |
| Unknown | 10 (1.2) | 1 (0.1) | 11 (0.7) | |
| LN status | ||||
| Negative | 497 (59.2) | 496 (59.0) | 993 (59.1) | 0.148 |
| Positive | 314 (37.4) | 299 (35.6) | 613 (36.5) | |
| Unknown | 29 (3.5) | 45 (5.4) | 74 (4.4) | |
| AJCC stage | ||||
| I | 380 (45.2) | 406 (48.3) | 786 (46.8) | 0.363 |
| II | 312 (37.1) | 303 (36.1) | 615 (36.6) | |
| III | 148 (17.6) | 131 (15.6) | 279 (16.6) | |
| ER status | ||||
| Negative | 589 (70.1) | 578 (68.8) | 1,167 (69.5) | 0.560 |
| Positive | 251 (29.9) | 262 (31.2) | 513 (30.5) | |
| PR status | ||||
| Negative | 645 (76.8) | 635 (75.6) | 1,280 (76.2) | 0.567 |
| Positive | 195 (23.2) | 205 (24.4) | 400 (23.8) | |
| HER2 status | ||||
| Negative | 187 (22.3) | 175 (20.8) | 362 (21.5) | 0.838 |
| Positive | 64 (7.6) | 60 (7.1) | 124 (7.4) | |
| Borderline | 7 (0.8) | 6 (0.7) | 13 (0.8) | |
| Unknown | 582 (69.3) | 599 (71.3) | 1,181 (70.3) | |
| Surgery type | ||||
| Mastectomy | 377 (44.9) | 354 (42.1) | 731 (43.5) | 0.527 |
| BCS | 462 (55.0) | 485 (57.7) | 947 (56.4) | |
| Unknown | 1 (0.1) | 1 (0.1) | 2 (0.1) | |
| Radiation | ||||
| No | 365 (43.5) | 350 (41.7) | 715 (42.6) | 0.717 |
| Yes | 440 (52.4) | 451 (53.7) | 891 (53.0) | |
| Unknown | 35 (4.2) | 39 (4.6) | 74 (4.4) |
AJCC = American Joint Committee on Cancer, BCS = breast conserving surgery, ER = estrogen receptor, PR = progesterone receptor, HER2 = human epidermal growth factor receptor 2, IDC = infiltrating ductal carcinoma, AAC = apocrine adenocarcinoma, IQR = interquartile range, LN = lymph node, NOS = no other specific, UD = undifferentiated.
aP-valuedetermined by Chi-square test comparing the matched AAC and IDC groups.
bIncluding American Indian/Alaskan native, and Asian/Pacific Islander, and others-unspecified.
cIncluding divorced, separated, single (never married), unmarried, domestic partner and widowed.
dIncluding grade 3 and undifferentiated.