Molecular Subtypes
Pathologists test every breast tumor for hormone receptors (ER/PR) and HER2. The result — the molecular subtype — is the single most important factor in choosing systemic therapy.
HR+/HER2− (Luminal A / B)
Fueled by estrogen and/or progesterone. Treated with endocrine therapy (tamoxifen, aromatase inhibitors), often combined with CDK4/6 inhibitors. Luminal A grows slowly; Luminal B has a higher Ki-67 and may need chemotherapy.
HER2-Positive
Overexpresses the HER2 protein. Once aggressive, now highly treatable with trastuzumab, pertuzumab and antibody-drug conjugates such as trastuzumab deruxtecan.
Triple-Negative (TNBC)
Lacks ER, PR and HER2. Treated with chemotherapy, and for many patients with immunotherapy (pembrolizumab) or sacituzumab govitecan; PARP inhibitors help BRCA carriers.
HER2-Low
Tumors with low HER2 expression (IHC 1+ or 2+/ISH−) may now benefit from HER2-directed antibody-drug conjugates.
Disease Staging Matrix
Stage combines tumor size (T), lymph-node involvement (N) and distant spread (M), refined by grade and biomarkers.
| Stage | What it means | Typical approach |
|---|---|---|
| Stage 0 (DCIS) | Abnormal cells confined to the milk ducts; non-invasive. | Lumpectomy ± radiation, or mastectomy; endocrine therapy if HR+. |
| Stage I | Small invasive tumor (≤2 cm), no or microscopic node spread. | Surgery, radiation after lumpectomy, systemic therapy by subtype. |
| Stage II | Tumor 2–5 cm and/or spread to a few axillary nodes. | Surgery plus chemo/targeted/endocrine therapy; neoadjuvant therapy common for HER2+ and TNBC. |
| Stage III | Locally advanced: large tumor, many nodes, or chest-wall/skin involvement. | Neoadjuvant systemic therapy, surgery, then radiation. |
| Stage IV (Metastatic) | Spread to distant organs such as bone, liver, lung or brain. | Long-term systemic therapy to control disease and preserve quality of life. |
Standard of Care Options
Neoadjuvant & Adjuvant Chemotherapy
Given before surgery to shrink tumors (and test response) or after surgery to lower recurrence risk.
Lumpectomy vs. Mastectomy
Breast-conserving surgery plus radiation offers survival equal to mastectomy for most early-stage patients. Sentinel node biopsy stages the armpit.
Radiation Therapy
Whole-breast, partial-breast or post-mastectomy radiation reduces local recurrence; hypofractionated schedules take 3–4 weeks.
CDK4/6 Inhibitors
Palbociclib, ribociclib and abemaciclib, combined with endocrine therapy, extend survival in HR+/HER2− advanced disease and reduce recurrence in high-risk early disease.
Signs & Symptoms to Report
- A new lump or thickening in the breast or armpit
- Change in breast size, shape or skin dimpling
- Nipple inversion, discharge (especially bloody) or scaling
- Redness, warmth or orange-peel skin (possible inflammatory breast cancer)
- Persistent breast or armpit pain that doesn't cycle with periods
Frequently Asked Questions
At what age should I start mammograms?
The USPSTF recommends screening mammography every two years for women aged 40 to 74. Women with a BRCA mutation, strong family history or prior chest radiation may need earlier screening with breast MRI.
Does a BRCA mutation mean I will get breast cancer?
No. BRCA1/2 carriers have a substantially higher lifetime risk, but many never develop cancer. Genetic counseling can explain enhanced screening, preventive medications and risk-reducing surgery.
Is breast cancer curable?
Most early-stage breast cancers (stages 0–III) are treated with curative intent, and five-year survival for localized disease is about 99%. Metastatic breast cancer is usually treatable rather than curable, with many patients living for years.
Can men get breast cancer?
Yes. About 1% of breast cancers occur in men. Any lump near the nipple in a man should be evaluated.
Should I consider a clinical trial?
Trials offer access to new therapies and close monitoring at every stage. ONCorg's navigators can match you with recruiting breast cancer trials at no cost.
Medically reviewed content for education only — not a substitute for advice from your oncology team.