Table 3.
Correlation between PIK3CA mutation status and clinical variables
| PIK3CA wild-type | PIK3CA mutated | P valuea | ||
| Pathological complete response (pCR) versus residual disease (RD) | RD | 95 (83%) | 18 (82%) | 1.000 |
| pCR | 20 (17%) | 4 (18%) | ||
| Unknown | 2 | 1 | - | |
| Residual cancer burden | 0 | 20 (22.0%) | 4 (26.7%) | 0.121 (0.166b) |
| I | 7 (7.7%) | 0 (0%) | ||
| II | 37 (40.7%) | 10 (66.7%) | ||
| III | 27 (29.7%) | 1 (6.7%) | ||
| Unknown | 26 | 8 | - | |
| Estrogen receptor (ER) status | ER- | 54 (46%) | 8 (35%) | 0.365 |
| ER+ | 63 (54%) | 15 (65%) | ||
| Progesterone receptor (PR) status | PR- | 71 (60.7%) | 11 (47,8%) | 0.259 |
| PR+ | 46 (39.3) | 12 (52,2%) | ||
| HER2 status | HER2- | 104 (89%) | 21 (91%) | 1.000 |
| HER2+ | 13 (11%) | 2 (9%) | ||
| Grade | Grade 1–2 | 46 (47%) | 10 (56%) | 0.612 |
| Grade 3 | 51 (53%) | 8 (44%) | ||
| Unknown | 20 | 5 | - | |
| Nodal status | Negative | 29 (25%) | 12 (52%) | 0.012 |
| Positive | 88 (75%) | 11 (48%) | ||
| Tumor size | T0 | 1 (1%) | 1 (4%) | 0.535 |
| T1 | 7 (6%) | 0 (0%) | ||
| T2 | 59 (50%) | 12 (52%) | ||
| T3 | 18 (15%) | 3 (13%) | ||
| T4 | 32 (27%) | 7 (30%) | ||
| Ethnicity | Asian | 2 (2%) | 1 (4%) | 0.505 |
| Black | 11 (9%) | 2 (9%) | ||
| Hispanic | 40 (34%) | 10 (43%) | ||
| Caucasian | 64 (55%) | 10 (43%) | ||
| Median age (minimum-maximum), years | 50 (28–73) | 52 (42–73) | - |
aChi-square test. bP value for comparison of residual cancer burden (RCB)-0 and RCB-I versus RCB-III. PIK3CA, phosphatidylinositol 3-kinase, catalytic, alpha polypeptide.