Table 2.
Variables affecting the SNB identification rate
| Variable | Not identified (n = 65), n (%) | Identified (n = 1,888), n (%) | P |
|---|---|---|---|
| Age (year) | 0.002 | ||
| <30 | 0 (0) | 5 (100) | |
| 30–49 | 9 (2) | 481 (98) | |
| 50–69 | 37 (3) | 1,163 (97) | |
| ≥70 | 19 (7) | 239 (93) | |
| Pathological tumor size (cm) | <0.001 | ||
| ≤1 | 14 (3) | 411 (97) | |
| 1–2 | 30 (3) | 999 (97) | |
| 2–3 | 6 (2) | 401 (98) | |
| 3–5 | 3 (5) | 55 (95) | |
| >5 | 3 (23) | 10 (77) | |
| Histology | 0.009 | ||
| Invasive ductal | 38 (3) | 1,378 (97) | |
| Invasive lobular | 2 (1) | 218 (99) | |
| Other | 16 (5) | 288 (95) | |
| Year of accrual | 0.043 | ||
| 2001 | 2 (1) | 151 (99) | |
| 2002 | 20 (6) | 325 (94) | |
| 2003 | 12 (3) | 467 (97) | |
| 2004 | 19 (3) | 530 (97) | |
| 2005 | 12 (3) | 415 (97) | |
| Method SNB | <0.001 | ||
| Blue dye only | 2 (11) | 17 (90) | |
| Radioactive tracer only | 18 (10) | 163 (90) | |
| Blue dye and radioactive tracer | 36 (2) | 1,708 (98) | |
| Lymphoscintigram | NA | ||
| Nonvisualization | 29 (23) | 99 (77) |
SNB sentinal node biopsy; NA not applicable; NS not significant