Table 1.
Clinicopathological characteristics of study groups.
| Characteristic | HER2-positive/ BRCA mutated (total, n = 115) n (%) |
HER2-positive/ BRCA wild type (total, n = 129) n (%) |
HER2-negative/ BRCA mutated (total, n = 222) n (%) |
HER2-negative/ BRCA wild type (total, n = 234) n (%) |
OR∗ (95% CI) |
P |
|---|---|---|---|---|---|---|
| Age | 1.4 (0.8-2.3); | 0.21 | ||||
| 18-49 | 68 (59) | 66 (51) | 115 (52) | 131 (56) | 1.3 (0.8-2.1); | 0.20 |
| ≥ 50 | 47 (41) | 63 (49) | 107 (48) | 103 (44) | 1.1 (0.7-1.8) | 0.57 |
| Ax lymph nodesa | 1.5 (0.9-2.5); | 0.14 | ||||
| Negative | 47 (47) | 69 (57) | 90 (50) | 110 (52) | 1.1 (0.7-1.8); | 0.71 |
| Positive | 52 (53) | 51 (43) | 91 (50) | 100 (48) | 1.2 (0.7-1.9) | 0.42 |
| Stage at diagnosisa | 0.6 (0.4-1.1); | 0.10 | ||||
| I-II | 62 (63) | 62 (52) | 122 (67) | 113 (54) | 1.2 (0.7-2.1); | 0.42 |
| IIIA | 37 (37) | 58 (48) | 59 (33) | 97 (46) | 0.7 (0.4-1.1) | 0.14 |
| Histologic gradea | 1.4 (0.8-2.5); 2.6 (1.6-4.2); 2.5 (1.5-4.1) |
0.26 | ||||
| 1-2 | 33 (29) | 45 (36) | 111 (52) | 117 (51) | 0.0001 | |
| 3 | 80 (71) | 80 (64) | 104 (48) | 113 (49) | 0.0002 | |
| Ki-67 indexa | 1.6 (0.9-2.7); | 0.11 | ||||
| Low | 30 (27) | 46 (37) | 113 (53) | 119 (52) | 3.0 (1.8-4.5); | <0.0001 |
| High | 80 (73) | 78 (63) | 100 (47) | 109 (48) | 2.9 (1.8-4.8) | <0.0001 |
| Hormone receptora | 1.0 (0.6-1.7); | 0.96 | ||||
| Positive | 46 (40) | 52 (41) | 111 (50) | 119 (51) | 1.5 (0.9-2.3); | 0.09 |
| Negative | 68 (60) | 76 (59) | 111 (50) | 114 (49) | 1.5 (0.9-2.4) | 0.06 |
| Type of surgerya | 0.8 (0.5-1.4); | 0.51 | ||||
| Quadrantectomy | 63 (58) | 68 (54) | 121 (55) | 104 (45) | 0.9 (0.6-1.4); | 0.63 |
| Mastectomy | 46 (42) | 59 (46) | 99 (45) | 128 (55) | 0.6 (0.4-0.9) | 0.02 |
| NACT/ACTa | 1.6 (0.8-3.2); | 0.21 | ||||
| Performed | 95 (87)b,c | 103 (81)b,c | 86 (39)c | 95 (41)c | 10.6 (5.7-19.7); | <0.0001 |
| Not performed | 14 (13) | 24 (19) | 134 (61) | 137 (59) | 9.8 (5.3-18.2) | <0.0001 |
| AETa | 1.1 (0.5-1.6); | 0.94 | ||||
| Performed | 44 (40) | 52 (41) | 109 (49) | 119 (51) | 1.4 (0.8-2.4); | 0.10 |
| Not performed | 65 (60) | 75 (59) | 111 (51) | 113 (49) | 1.5 (0.8-2.3) | 0.07 |
| iDFS eventsd ─ n | 14 | 18 | 23 | 15 |
5-year iDFS rates (95% CI)e 88% (80-95%); 86% (78-93%); 89% (84-94%); 93% (90-97%) |
|
| Death eventsd ─ n | 7 | 4 | 12 | 3 |
5-year OS rates (95% CI)e 93% (88-99%); 97% (93-100%); 94% (90-97%); 99% (97-100%) |
|
Abbreviations: n, number; OR, odds ratio; %, percentage; CI, confidence interval; Ax, axillary; NACT, neoadjuvant chemotherapy; ACT adjuvant chemotherapy; AET, adjuvant endocrine therapy; iDFS, invasive disease-free survival; OS, overall survival.
Unadjusted ORs and their 95% CIs were provided for categorical variables (positive [bad] outcomes: early age at onset, positive axillary lymph node status, stage III at diagnosis, histologic grade 3, high ki-67 index, negative hormone receptor status, mastectomy surgery, neo/adjuvant chemotherapy and endocrine therapy) of the reference group (HER2-positive/BRCA mutated cases) compared to each of the three control groups (HER2-positive/BRCA wild type; HER2-negative/BRCA mutated; HER2-negative/BRCA wild type).
Numbers in these categories do not sum to the total because of missing data.
All HER2-positive cases treated with neoadjuvant and/or adjuvant chemotherapy also received trastuzumab.
None of the HER2-positive/BRCA mutated cases, none of the HER2-positive/BRCA wild type, 20 of the HER2-negative/BRCA mutated, and 10 out of the HER2-negative/BRCA wild type controls received platinum salts in the neo-/adjuvant setting.
Median follow-up of 83.7 months.
iDFS and OS rates of the reference group (HER2-positive/BRCA mutated cases) and of the three control groups (HER2-positive/BRCA wild type; HER2-negative/BRCA mutated; HER2-negative/BRCA wild type). Three events of second non-breast primary cancer (ovarian cancer) were observed in the HER2-negative/BRCA mutated controls.