Table 1.
Distribution of clinico-pathological features of 2,653 incident invasive breast tumors by Ki67 positivity, Nurses’ Health Study, 1976–2006
| Ki67 <14% n=1954 (%) | Ki67 ≥14% n=699 (%) | p valuea | |
|---|---|---|---|
| Age at diagnosis | 58.9 (8.9) | 60.7 (9.4) | <0.0001 |
| Tumor size (cm) | 0.0007 | ||
| < 2.0 | 1250 (67) | 384 (58) | |
| 2.1–4.0 | 459 (25) | 222 (33) | |
| 4.0+ | 160 (9) | 61 (9) | |
| Tumor grade | <0.0001 | ||
| Well differentiated | 403 (22) | 86 (13) | |
| Moderately differentiated | 963 (51) | 282 (42) | |
| Poorly differentiated | 508 (27) | 310 (46) | |
| Lymph node involvement | 0.21 | ||
| No nodes involved | 1218 (67) | 405 (64) | |
| 1–3 nodes | 361 (20) | 146 (23) | |
| 4–9 nodes | 146 (8) | 47 (7) | |
| 10+ nodes | 89 (5) | 38 (6) | |
| Tumor stage at diagnosis | 0.004 | ||
| Stage 1 | 1073 (55) | 324 (46) | |
| Stage 2 | 607 (31) | 272 (39) | |
| Stage 3 | 274 (14) | 103 (15) | |
| ER status | <0.0001 | ||
| ER+ | 1603 (82) | 449 (64) | |
| ER− | 342 (18) | 249 (36) | |
| PR status | <0.0001 | ||
| PR+ | 1405 (72) | 380 (55) | |
| PR− | 541 (28) | 316 (45) | |
| Joint ER/PR status | <0.0001 | ||
| ER+/PR+ | 1376 (71) | 363 (52) | |
| ER+/PR− | 225 (12) | 85 (12) | |
| ER−/PR+ | 27 (1) | 17 (2) | |
| ER−/PR− | 315 (16) | 231 (33) | |
| HER2 status | <0.0001 | ||
| HER2+ | 360 (19) | 196 (28) | |
| HER2− | 1565 (81) | 493 (72) | |
| EGFR status | <0.0001 | ||
| EGFR+ | 288 (15) | 250 (37) | |
| EGFR− | 1624 (85) | 427 (63) | |
| CK5/6 status | <0.0001 | ||
| CK5/6+ | 172 (9) | 145 (21) | |
| CK5/6− | 1745 (91) | 545 (79) | |
| Surgery | 0.12 | ||
| No | 3 (0) | 2 (0) | |
| Lumpectomy | 642 (34) | 247 (37) | |
| Mastectomy | 1235 (66) | 412 (62) | |
| Unknown type of surgery | 1 (0) | 1 (0) | |
| Radiation | 0.24 | ||
| Yes | 833 (55) | 321 (58) | |
| No | 674 (45) | 231 (42) | |
| Chemotherapy | <0.0001 | ||
| Yes | 681 (45) | 324 (58) | |
| No | 845 (55) | 234 (42) | |
| Tamoxifen | 0.01 | ||
| Yes | 1139 (76) | 371 (70) | |
| No | 360 (24) | 157 (30) |
Numbers may not add to column totals due to missing data and percentages may not add to 100 due to rounding
a
χ2 tests for all variables except Kruskal-Wallis test for age at diagnosis; p-trend for categorical variables with more than two categories