Table 2.
Factors associated with failure to identify a SLN
| Variable | SLN ID rate (%) |
Failure to identify a SLN (%) |
Odds Ratio** (95% CI) |
p-value |
|---|---|---|---|---|
| Age | ||||
| < 50 years old | 324/345 (93.9) | 21/345 (6.1) | 0.70 (0.39-1.26) | 0.238 |
| ≥ 50 years old | 315/344 (91.6) | 29/344 (8.4) | 1 | |
| BMI | ||||
| < 25.0 (underweight/normal) | 185/195 (94.9) | 10/195 (5.1) | 1 | 0.176 |
| ≥ 25.0 (overweight/obese) | 452/492 (91.9) | 40/492 (8.1) | 1.64 (0.80-3.31) | |
| Unknown | 2/2 (100) | 0/2 (0) | -- | |
| Clinical T stage at presentation | ||||
| Tis/T0/T1 | 88/95 (92.6) | 7/95 (7.4) | 1 | |
| T2 | 356/379 (93.9) | 23/379 (6.1) | 0.81 (0.34-1.95) | 0.642 |
| T3/4 | 194/214 (90.7) | 20/214 (9.3) | 1.30 (0.53-3.18) | 0.571 |
| Unknown | 1/1 (100) | 0/1 (0) | ||
| Clinical N stage at presentation | ||||
| N1 | 605/651 (92.9) | 46/651 (7.1) | 1 | 0.428 |
| N2 | 34/38 (89.5) | 4/38 (10.5) | 1.55 (0.53-4.55) | |
| Approximated subtype | ||||
| HR positive/HER2 negative | 287/311 (92.3) | 24/311 (7.7) | 1 | |
| HER2 positive | 192/209 (91.9) | 17/209 (8.2) | 1.06 (0.55-2.02) | 0.863 |
| Triple negative | 158/166 (95.2) | 8/166 (4.8) | 0.61 (0.27-1.38) | 0.232 |
| Unable to define | 2/3 (66.0) | 1/3 (33.0) | ||
| Duration of NAC | ||||
| < 135 days | 390/415 (94.0) | 25/415 (6.0) | 1 | 0.127 |
| ≥ 135 days | 249/274 (90.9) | 25/274 (9.1) | 1.57 (0.88-2.79) | |
| Palpable adenopathy after NAC | ||||
| Yes | 85/88 (96.6) | 3/88 (3.4) | 0.41 (0.13-1.36) | 0.145 |
| No | 526/571 (92.1) | 45/571 (7.9) | 1 | |
| Not stated | 28/30 (93.3) | 2/30 (6.7) | ||
| Anti-HER2 therapy (among the 209 HER2 positive cases) | ||||
| Yes | 168/185 (90.8) | 17/185 (9.2) | 0.229 | |
| No | 24/24 (100) | 0/27 (0) | ||
| Site of tracer injection | ||||
| Multiple sites | 138/149 (92.6) | 11/149 (7.4) | 1 | |
| Subareolar | 409/435 (94.0) | 26/435 (6.0) | 0.80 (0.38-1.66) | 0.631 |
| Peri-tumoral | 49/57 (86.0) | 8/57 (14.0) | 2.05 (0.78-5.39) | 0.146 |
| Intradermal | 17/19 (89.5) | 2/19 (10.5) | 1.48 (0.30-7.23) | 0.544 |
| Unknown | 26/29 (89.7) | 3/29 (10.3) | -- | -- |
| Tracers used | ||||
| Blue dye alone | 22/28 (78.6) | 6/28 (21.4) | 4.10 (1.56-10.78) | 0.004 |
| Radiocolloid alone | 106/116 (91.4) | 10/116 (8.6) | 1.42 (0.68-2.96) | 0.352 |
| Dual tracers | 511/545 (93.8) | 34/545 (6.2) | 1 | |
| Mapping approach | ||||
| Blue dye alone | 22/28 (78.6) | 6/28 (21.4) | 3.82 (1.47-9.92) | 0.006 |
| Radiocolloid +/− Blue dye | 617/661(93.3) | 44/661 (6.7) | 1 | |
| Number of tracers used | ||||
| Single tracer | 128/144 (88.9) | 16/144 (11.1) | 1 | 0.048 |
| Dual tracer | 511/545 (93.8) | 34/545 (6.2) | 0.53 (0.29-0.99) | |
| Breast Surgery* | ||||
| Lumpectomy | 255/272 (93.7) | 17/272 (6.3) | 0.79 (0.43-1.46) | 0.458 |
| Mastectomy | 381/413 (92.3) | 32/413 (7.6) | 1 | |
| Year of Surgery | ||||
| 2009-2010 | 339/368 (92.1) | 29/368 (7.9) | 1.22 (0.68-2.190 | 0.500 |
| 2011-2012 | 300/321 (93.5) | 21/300 (6.5) | 1 | |
*
4 patients did not have breast surgery
**
estimates from logistic regression modeling