TABLE 6.
Association between IDFS events and chemotherapy in different IHC3 risk groups
| IHC3 model | Data set | Chemotherapy group (cases [%]) | Non‐chemotherapy group (cases [%]) | P value |
|---|---|---|---|---|
| pLR | Total (n = 456) | 38 (100) | 418 (100) | |
| IDFS event (n = 28) | 2 (5.3) | 26 (6.2) # | 1.000* | |
| No IDFS event (n = 428) | 36 (94.7) | 392 (93.8) | ||
| pHR | Total (n = 79) | 50 (100) | 29 (100) | |
| IDFS event (n = 13) | 9 (18) | 4 (13.8) | 0.864* | |
| No IDFS event (n = 66) | 41 (82) | 25 (86.2) |
pLR predictive low‐recurrence risk; pHR predictive high‐recurrence risk; IDFS invasive disease‐free survival; IHC immunohistochemistry. # Among the 26 events, five were secondary primary cancers. *Pearson chi‐square test.