Table 1.
Patient, treatment, and tumor-related characteristics of all patients.
| Characteristics | APBI (N=173) | AWBI (N=300) | p-value | |||
|---|---|---|---|---|---|---|
| Age at diagnosis (years) | Median (range) | 61 | (51–81) | 58 | (50–80) | |
| Histology | <0.001 | |||||
| DCIS | 5 | (3%) | 54 | (18%) | ||
| IDC | 166 | (96%) | 226 | (75%) | ||
| ILC | 0 | (0%) | 17 | (6%) | ||
| Other | 2 | (1%) | 3 | (1%) | ||
| Tumor size | 0.881 | |||||
| <1.5 cm | 102 | (59%) | 179 | (60%) | ||
| ≥1.5 cm | 71 | (41%) | 121 | (40%) | ||
| Histologic grade | <0.001 | |||||
| I (low) | 44 | (25%) | 38 | (13%) | ||
| II (intermediate) | 125 | (72%) | 161 | (54%) | ||
| III (high) | 4 | (2%) | 101 | (33%) | ||
| Estrogen receptor status | <0.001 | |||||
| Positive | 173 | (100%) | 204 | (68%) | ||
| Negative | 0 | (0%) | 96 | (32%) | ||
| HER2 status | <0.001 | |||||
| Positive | 1 | (1%) | 72 | (24%) | ||
| Negative | 172 | (99%) | 228 | (76%) | ||
| Resection margin | <0.001 | |||||
| Negative | 147 | (85%) | 198 | (66%) | ||
| Close | 26 | (15%) | 87 | (29%) | ||
| Positive | 0 | (0%) | 15 | (5%) | ||
| Chemotherapy | <0.001 | |||||
| Yes | 0 | (0%) | 91 | (30%) | ||
| No | 173 | (100%) | 209 | (70%) | ||
| Endocrine therapy | <0.001 | |||||
| Tamoxifen | 56 | (32%) | 98 | (33%) | ||
| Aromatase inhibitor | 117 | (68%) | 108 | (36%) | ||
| None | 0 | (0%) | 94 | (31%) | ||
| Anti-HER2 therapy | <0.001 | |||||
| Yes | 0 | (0%) | 34 | (11%) | ||
| No | 173 | (100%) | 266 | (89%) | ||
| Boost radiation | <0.001 | |||||
| Yes | 0 | (0%) | 257 | (86%) | ||
| No | 173 | (100%) | 43 | (14%) | ||
DCIS, ductal carcinoma in situ; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; HER2, human epidermal growth factor receptor 2; APBI, accelerated partial breast irradiation; AWBI, accelerated whole-breast irradiation.