Table 1.
Patient characteristics at baseline for circulating tumor cell count before chemotherapy (n = 2026)*
| Characteristic | CTC ≥ 1† No. (%) | CTC = 0† No. (%) | P | CTC ≥ 5† No. (%) | CTC = 0–4† No. (%) | P |
|---|---|---|---|---|---|---|
| No. of patients | 435 (21.5) | 1591 (78.5) | 63 (3.1) | 1963 (96.9) | ||
| Age in years (mean ± SD) | 53.8±10.3 | 53.2±10.5 | .26‡ | 55.03+9.87 | 53.30+10.52 | .19‡ |
| Tumor size¶ | ||||||
| pT1a | 1 (0.2) | 16 (1.0) | .19§ | 0 (0) | 17 (0.8) | .31§ |
| pT1b | 19 (4.4) | 86 (5.4) | 3 (4.8) | 102 (5.2) | ||
| pT1c | 139 (32.0) | 561 (35.3) | 20(31.8) | 680 (34.6) | ||
| pT2–4 | 268 (61.6) | 906 (56.9) | 40 (63.5) | 1134 (57.8) | ||
| pTx | 7 (1.6) | 22 (1.4) | 0 (0) | 29 (1.5) | ||
| Lymph node metastases¶ | ||||||
| Absent (pN0)/ pNX | 136 (31.3) | 556 (35.0) | <.001§ | 15 (23.8) | 659 (33.6) | <.001§ |
| 1–3 axillary (pN1) | 178 (40.9) | 747 (47.0) | 23 (36.5) | 921 (46.9) | ||
| 4–9 axillary (pN2) | 72 (16.5) | 208 (13.0) | 16 (25.4) | 257 (13.1) | ||
| ≥10 axillary (pN3) | 49 (11.3) | 80 (5.0) | 9 (14.3) | 126 (6.4) | ||
| Grading# | ||||||
| G1 | 14 (3.2) | 85 (5.3) | .19‡ | 1 (1.6) | 98 (5.0) | .12‡ |
| G2 | 206 (47.4) | 740 (46.5) | 37 (58.7) | 909 (46.3) | ||
| G3 | 212 (48.7) | 753 (47.3) | 25 (39.7) | 940 (47.9) | ||
| Gx | 3 (0.7) | 13 (0.8) | 0 (0) | 16 (0.8) | ||
| Hormone receptor status | ||||||
| Negative | 128 (29.4) | 450 (28.3) | .64ǁ | 13 (20.6) | 565 (28.8) | .16ǁ |
| Positive | 307 (70.6) | 1141 (71.7) | 50 (79.4) | 1398 (71.2) | ||
| Her2-neu status | ||||||
| Undefined | 10 (2.3) | 41 (2.6) | .54ǁ | 3 (4.8) | 48 (2.4) | .95ǁ |
| Negative | 322 (74.0) | 1152 (72.4) | 45 (71.4) | 1429 (72.8) | ||
| Positive | 103 (23.7) | 398 (25.0) | 15 (23.8) | 486 (24.8) | ||
| Histological type | ||||||
| Undefined | 12 (.8) | 2 (0.5) | .15§ | 0 (0) | 14 (0.7) | .13§ |
| Ductal | 344 (79.1) | 1285 (80.8) | 45 (71.4) | 1584 (80.7) | ||
| Lobular | 62 (14.3) | 176 (11.1) | 12 (19.0) | 226 (11.5) | ||
| Mixed ductal-lobular | 27 (6.2) | 118 (7.4) | 6 (9.5) | 139 (7.1) | ||
| Menopausal status | ||||||
| Premenopausal | 169 (38.9) | 672 (42.2) | .20ǁ | 17 (27.0) | 824 (42.0) | .02ǁ |
| Postmenopausal | 266 (61.1) | 919 (57.8) | 46 (73.0) | 1139 (58.0) | ||
| Primary operation | ||||||
| Breast conserving | 295 (67.8) | 1119 (70.3) | .27ǁ | 45 (71.4) | 1369 (69.7) | .84ǁ |
| Mastectomy | 138 (31.7) | 460 (28.9) | 18 (28.6) | 580 (29.5) | ||
| Radiotherapy | ||||||
| Performed | 341 (78.4) | 1211 (76.1) | .11ǁ | 46 (73.0) | 1506 (76.7) | .68ǁ |
| Not performed | 94 (21.6) | 380 (23.9) | 17 (27.0) | 457 (23.3) | ||
| Systemic therapy | ||||||
| Chemotherapy–FEC-D | 205 (47.1) | 820 (51.5) | .10ǁ | 26 (41.3) | 999 (50.9) | .13ǁ |
| Chemotherapy–FEC-DG | 230 (52.9) | 771 (48.5) | 37 (58.7) | 964 (49.1) | ||
| Endocrine treatment | 266 (61.2) | 967 (60.7) | .88ǁ | 32 (50.8) | 990 (50.4) | .78ǁ |
| Trastuzumab | 83 (19.4) | 329 (21.2) | .41ǁ | 9 (14.3) | 229 (11.7) | .52ǁ |
* CTC = circulating tumor cell; FEC-D = fluorouracil-epirubicin-cyclophosphamide (500/100/500 mg/m2, FEC) followed by docetaxel (100 mg/mg2); FEC-DG = fluorouracil-epirubicin-cyclophosphamide (500/100/500 mg/m2, FEC) followed by gemcitabine (1,000 mg/m2 d1,8)-docetaxel (75 mg/m2); SD = standard deviation.
† Per 30mL of blood.
‡ Two-sided t test.
§ Two-sided Cochran–Armitage test for trend.
ǁ Two-sided χ2 test.
¶ Tumor-node-metastasis (TNM) was classified according to the revised American Joint Committee on Cancer TNM classification (23).
# Histopathological grading of the primary tumors was performed according to Elston–Ellis (24).