| Breast Cancer Type | Pathology / Features | Hormone Receptor Status | Prognosis | Common Treatments | Pharmacotherapy & Dosing Examples | Key Side Effects & Toxicities | Monitoring & Pharmacist Considerations |
|---|---|---|---|---|---|---|---|
| Ductal Carcinoma In Situ (DCIS) | Non-invasive, confined to ducts | Usually ER+/PR+ | Excellent if treated | Surgery ± radiation, hormonal therapy | Tamoxifen 20 mg PO daily × 5 years | Hot flashes, VTE risk, endometrial changes | Monitor adherence, VTE, bleeding; support radiation adherence |
| Lobular Carcinoma In Situ (LCIS) | Non-invasive, confined to lobules | Usually ER+ | Not cancer; ↑ risk (~8–10x) | Surveillance, chemoprevention | Tamoxifen 20 mg daily or Raloxifene 60 mg daily | Tamoxifen: VTE, endometrial risk; Raloxifene: VTE risk | Educate on chemoprevention; promote surveillance adherence |
| Invasive Ductal Carcinoma (IDC) | Most common invasive; ductal origin | Variable (ER+/PR+/HER2− common) | Variable, stage dependent | Surgery, chemo, hormonal, targeted therapy |
Chemo (AC-T): Doxorubicin + Cyclophosphamide q3w ×4, then Paclitaxel weekly ×12 Hormonal: Tamoxifen 20 mg daily or Anastrozole 1 mg daily Targeted: Trastuzumab IV dosing per protocol |
Chemo: myelosuppression, nausea, alopecia |
Tamoxifen: VTE, endometrial risk Trastuzumab: cardiotoxicity CBC, cardiac monitoring, antiemetics; counsel on side effects |
| Invasive Lobular Carcinoma (ILC) | Invasive lobular origin, often multifocal | Often ER+/PR+, HER2− | Slightly better than IDC | Similar to IDC treatments | Same as IDC | Same as IDC | Same as IDC |
| Triple Negative Breast Cancer (TNBC) | ER−, PR−, HER2−; aggressive | ER−, PR−, HER2− | Poor prognosis | Chemotherapy; immunotherapy emerging |
Dose-dense AC-T or carboplatin + paclitaxel |
Chemo: myelosuppression, neuropathy Immunotherapy: infusion reactions, immune AEs |
CBC, neuropathy checks, immune AE monitoring; counsel patients |
| HER2-Positive Breast Cancer | HER2 overexpressing, aggressive tumor | ER variable, HER2+ | Improved with targeted therapy | Chemo + trastuzumab ± pertuzumab |
Trastuzumab: 8 mg/kg loading, then 6 mg/kg q3w Pertuzumab: 840 mg loading, then 420 mg q3w |
Cardiotoxicity, infusion reactions | LVEF monitoring (echo/MUGA), infusion monitoring |
| Inflammatory Breast Cancer (IBC) | Rapid skin involvement, edema, erythema | Often ER−/PR−/HER2+ | Poor prognosis | Neoadjuvant chemo + targeted therapy + surgery + radiation | Chemo + trastuzumab-based regimen if HER2+; otherwise chemo only | Aggressive chemo toxicities, skin symptoms | Support intensive therapy; monitor toxicities |
| Phyllodes Tumor | Fibroepithelial tumor; benign or malignant | Usually hormone receptor negative | Variable prognosis | Surgery mainstay; chemo/radiation if malignant | No standard chemo role | N/A | Focus on perioperative care |
| Metaplastic Breast Cancer | Rare, heterogeneous histology | Usually triple negative | Poor prognosis | Chemotherapy mainstay | Similar to TNBC chemo regimens | Similar to TNBC | Monitor chemo toxicity; support adherence |
Additional Pharmacist Notes:
- Hormonal agents (tamoxifen, aromatase inhibitors) require counseling on side effects and adherence; watch for VTE and bone health.
- HER2-targeted therapy demands baseline and ongoing cardiac monitoring.
- Chemotherapy toxicity management is essential (myelosuppression, nausea, neuropathy).
- Immunotherapy requires vigilance for immune-related adverse events.
- Support patients through complex regimens and educate on symptom management.