Table 1 Baseline characteristics by study arm
|  |  | APBI N = 42 | WBI N = 42 | p-value |
|---|---|---|---|---|
Age (years) | Median (Range) | 65 (52, 77) | 64 (51, 81) | 0.070 |
Phototype | I/II | 19 (45%) | 20 (48%) | 0.827 |
| Â | III/IV | 23 (55%) | 22 (52%) | Â |
Laterality | left | 18 (43%) | 21 (50%) | 0.512 |
| Â | right | 24 (57%) | 21 (50%) | Â |
Grade | G1 | 25 (60%) | 24 (57%) | 0.825 |
| Â | G2 | 17 (40%) | 18 (43%) | Â |
Histology | DCIS | 2 (4.8%) | 2 (4.8%) | 0.911 |
| Â | NST | 34 (81%) | 32 (76%) | Â |
| Â | Other | 6 (14%) | 8 (19%) | Â |
Tumor size (mm) | 0–9 | 24 (57%) | 18 (43%) | 0.422 |
|  | 10–14 | 13 (31%) | 17 (40%) |  |
|  | 15–20 | 5 (12%) | 7 (17%) |  |
ER (%) | 90 | 0 (0%) | 3 (7.1%) | 0.121 |
| Â | 95 | 2 (4.8%) | 4 (9.5%) | Â |
| Â | 100 | 40 (95%) | 35 (83%) | Â |
PR (%) | < 10 | 8 (19%) | 9 (21%) | 0.267 |
|  | 10–79 | 10 (24%) | 16 (38%) |  |
|  | 80–100 | 24 (57%) | 17 (40%) |  |
Ki67 (%) | < 15 | 21 (50%) | 25 (60%) | 0.583 |
|  | 15–20 | 13 (31%) | 12 (29%) |  |
|  | > 20 | 8 (19%) | 5 (12%) |  |
Number of sentinel lymph nodes removed | 1 | 25 (60%) | 22 (55%) | 0.462 |
2 | 8 (19%) | 12 (30%) | Â | |
|  | > 2 | 9 (21%) | 6 (15%) |  |
| Â | Omitted | 0 | 2 | Â |
Negative resection margin (mm) | Median (Range) | 5 (2, 10) | 5.5 (2, 15) | 0.718 |
Cavity size (mm) | Median (Range) | 30 (16, 69) | 31 (13, 65) | 0.629 |
|  | < 30 | 22 (52%) | 21 (50%) | 0.827 |
|  | ≥ 30 | 20 (48%) | 21 (50%) |  |
Endocrine therapy during RT | None | 9 (21%) | 4 (9.5%) | 0.345 |
| Â | AI | 4 (9.5%) | 5 (12%) | Â |
| Â | Tamoxifen | 29 (69%) | 33 (79%) | Â |