Table 1.
Patient and Tumor Characteristics for Patients with IM Drainage (IM Only or IM and Axillary Drainage) and Without IM Drainage on Preoperative Lymphoscintigraphya
| Characteristic | Total n = 1772 | IM Drainage n = 334 | No IM Drainage n = 1438 | P Value |
|---|---|---|---|---|
| Age, y | <0.0001 | |||
| Mean | 56.1 | 53 | 56.8 | |
| Median | 56 | 52 | 56 | |
| Range | 23–88 | 26–83 | 23–88 | |
| Tumor location | 0.001 | |||
| UOQ | 688 (38.8) | 102 (30.5) | 586 (40.8) | |
| Other quadrant | 1084 (61.2) | 232 (69.5) | 852 (59.2) | |
| Tumor location | 0.002 | |||
| Medial | 440 (24.8) | 105 (31.4) | 335 (23.3) | |
| Lateral or central | 1332 (75.2) | 229 (68.6) | 1103 (76.7) | |
| Tumor stage | 0.1 | |||
| T1 | 1353 (76.4) | 268 (80.2) | 1085 (75.5) | |
| T2 | 383 (21.6) | 62 (18.6) | 321 (22.3) | |
| T3 | 36 (2.0) | 4 (1.2) | 32 (2.2) | |
| Histology | 0.1 | |||
| IDC | 1354 (76.4) | 268 (80.2) | 1086 (75.5) | |
| ILC | 126 (7.1) | 15 (4.5) | 111 (7.7) | |
| IDC and ILC | 153 (8.6) | 24 (7.2) | 129 (9.0) | |
| Other | 139 (7.8) | 27 (8.1) | 112 (7.8) | |
| Number of axillary SLNs identified | 0.9b | |||
| Mean | 2.8 | 2.8 | 2.8 | |
| Median | 2 | 2.5 | 2 | |
| Range | 0–10 | 0–9 | 0–10 | |
| Final tumor size, cm | 0.02b | |||
| Mean | 1.6 | 1.5 | 1.6 | |
| Median | 1.4 | 1.2 | 1.5 | |
| Range | 0.005–13 | 0.05–7 | 0.005–13 | |
| Positive SLNs | 0.4 c | |||
| Yes | 405 (23.1 | 69 (21.2) | 336 (23.5) | |
| No | 1348 (76.9) | 256 (78.8) | 1092 (76.5) | |
| Not identified | 19 | 9 | 10 | |
| ER status | 0.5c | |||
| Positive | 1336 (75.4) | 246 (73.6) | 1090 (75.8) | |
| Negative | 342 (19.3) | 69 (20.7) | 273 (19.0) | |
| Unknown | 94 (5.3) | 19 (5.7) | 75 (5.2) | |
| PR status | 0.03c | |||
| Positive | 1096 (61.9) | 190 (56.9) | 906 (63.0) | |
| Negative | 552 (31.2) | 120 (35.9) | 432 (30.0) | |
| Unknown | 124 (7.0) | 24 (7.2) | 100 (7.0) | |
| HER-2 status | 0.1c | |||
| Positive | 236 (13.3) | 53 (15.9) | 183 (12.7) | |
| Negative | 1300 (73.4) | 238 (71.3) | 1062 (73.8) | |
| Unknown | 236 (13.3) | 43 (12.8) | 193 (13.4) | |
| Nuclear grade | 0.4c | |||
| 1 | 252 (14.2) | 50 (15.0) | 202 (14.1) | |
| 2 | 941 (53.1) | 167 (50.0) | 774 (54.1) | |
| 3 | 571 (32.2) | 117 (35.0) | 454 (31.8) | |
| Unknown | 8 (0.5) | 0 (0) | 8 (0.06) |
IM indicates internal mammary; UOQ, upper outer quadrant; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; SLN, sentinel lymph node; ER, estrogen receptor; PR, progesterone receptor.
a
Data are number of patients (%) unless otherwise specified.
b
Wilcoxon rank sum test.
c
P value calculated after excluding “Unknown” or “Not identified” category.