Table 2.
Treatment-oriented classification of subgroups of breast cancer
| Clinical grouping | Notes |
|---|---|
| Triple-negative | Negative ER, PgR, and HER2 |
| Hormone receptor-negative and HER2-positive | ASCO/CAP guidelines |
| Hormone receptor-positive and HER2-positive | ASCO/CAP guidelines |
| Hormone receptor-positive and HER2-negative luminal disease as a spectrum: | ER and/or PgR positive ≥1%a |
| High receptor, low proliferation, low tumor burden (luminal A-like) | Multiparameter molecular marker ‘favorable prognosis’ if available. High ER/PgR and clearly low Ki-67b. Low or absent nodal involvement (N 0–3), smaller T size (T1 T2). |
| Intermediate | Multiparameter molecular marker ‘intermediate’ if availablec. Uncertainty persists about degree of risk and responsiveness to endocrine and cytotoxic therapies. |
| Low receptor, high proliferation, high tumor burden (luminal B-like) | Multiparameter molecular marker ‘unfavorable prognosis’ if available. Lower ER/PgR with clearly high Ki-67b. More extensive nodal involvement, histological grade 3, extensive lymphovascular invasion, larger T size (T3). |
aER values between 1% and 9% were considered equivocal. Thus, endocrine therapy alone cannot be relied upon for patients with these values.
bKi-67 scores should be interpreted in the light of local laboratory values: as an example, if a laboratory has a median Ki-67 score in receptor-positive disease of 20%, values of 30% or above could be considered clearly high; those of 10% or less clearly low.
cNot all multiparameter molecular marker tests report an intermediate score.