Table of Contents
Overview – Breast Cancers
Breast cancers are the most common malignancy affecting women worldwide, with ductal carcinomas making up the majority. These cancers arise from epithelial cells of the ducts or lobules and are influenced by hormonal, genetic, and environmental factors. Understanding risk factors, screening strategies, diagnostic pathways, subtypes, and management is essential for safe clinical practice and exam preparation.
Aetiology & Risk Factors
Hormonal (Sporadic)
- Female sex (99% of cases)
- Age: Peak incidence between 50–69 years
- Late parity or nulliparity increases risk
- Prolonged oestrogen exposure:
- Early menarche
- Late menopause
- Hormone replacement therapy (HRT)
- Oral contraceptives: Slight ↑ breast cancer risk; but ↓ endometrial cancer risk
- Proliferative fibrocystic disease
Genetic (Familial)
- Responsible for ~30% of breast cancers
- Increased risk with:
- Multiple first-degree relatives with breast cancer
- BRCA1 or BRCA2 gene mutations
- ER-negative or HER2-positive tumours are more common in younger women
Environmental
- Radiation exposure
- Pesticide exposure
Pathogenesis
- Arises from ductal epithelial hyperplasia
→ Dysplasia → Carcinoma in situ → Invasive carcinoma - Most commonly forms ductal carcinoma
- Driven by hormonal and genetic mutations
Clinical Features
General Signs
- Painless, firm, irregular, fixed breast lump
- Nipple retraction
- Skin puckering or dimpling
- Peau d’orange (lymphatic obstruction)
- Axillary lymphadenopathy
Ductal Carcinoma In Situ (DCIS)
- Often asymptomatic
- May present with bloody nipple discharge
- Detected via screening mammogram
- Non-invasive, but may progress to invasive carcinoma
Invasive Ductal Carcinoma
- Most common type (“schirrhous” variant)
- Features:
- Nipple inversion
- Skin changes (puckering, peau d’orange)
- Axillary nodes
- Quadrant distribution:
- 50% Upper Outer Quadrant
- 10% in other quadrants
- 20% Subareolar region
Diagnosis – Triple Assessment
- Clinical examination
- Palpation of lump, lymph nodes
- Imaging
- Mammography (low-dose X-ray)
- Detects densities and calcifications
- Sensitive; more effective with age
- Biopsy
- Core needle or FNA
- Histopathology: pleomorphism, dysplasia
- Receptor status: ER, HER2, PR, BRCA1/2 testing
2. https://www.cancer.org/cancer/breast-cancer/screening-tests-and-early-detection/breast-biopsy/fine-needle-aspiration-biopsy-of-the-breast.html
Prognostic Classification
Molecular Subtypes
- Luminal A (Best prognosis)
- ER+, HER2−
- Responsive to tamoxifen
- ~98% 5-year survival
- Luminal B
- ER+, HER2+
- Requires chemotherapy
- Intermediate prognosis
- Basal-like / Triple Negative
- ER−, PR−, HER2−
- Often BRCA1-positive
- Poor prognosis, affects younger women
- HER2-Enriched
- HER2+, ER/PR−
- Aggressive; early brain metastasis
- Treated with trastuzumab (Herceptin)
- ~16% 5-year survival
Staging – TNM System
| Stage | TNM Criteria | 5-Year Survival |
|---|---|---|
| 0 | DCIS | 99% |
| I | T1 N0 M0 | 92% |
| II | T2 N1 M0 | 65–82% |
| III | T3 N2 M0 | 44–50% |
| IV | Any T N+ M+ | 14% |
- Investigations:
- CXR, CT/MRI, PET, Bone scan
- Mammogram and ultrasound if not yet done
2. Unattributable
Management
DCIS (Stage 0)
- Breast-conserving surgery
- Radiotherapy
- Hormonal therapy (if ER+)
Early Breast Cancer (Stages I–II)
- Surgery: Lumpectomy or mastectomy
- Chemotherapy: Reduces recurrence
- Radiotherapy: Standard post-op
- Hormonal therapy (if ER+)
- Targeted therapy (if HER2+)
Locally Advanced & Inflammatory Breast Cancer (Stages III)
- Initial chemotherapy
- Mastectomy ± nodal resection
- Radiotherapy
- Targeted and/or hormonal therapy depending on receptor status
Metastatic Breast Cancer (Stage IV)
- Hormonal therapy: first-line for ER+
- Chemotherapy: for ER− or aggressive disease
- Targeted therapy (e.g. trastuzumab for HER2+)
- Radiotherapy: palliative for pain control or organ compression
- Surgery: rarely used, but may alleviate symptoms
Screening & Prevention
Population Screening
- Breast self-exam: monthly from 18 years
- Clinical breast exam: annually from 25 years
- Mammography:
- Every 1–2 years from age 40
- Yearly if high-risk (e.g. BRCA-positive)
BRCA Mutation Management
- Prophylactic double mastectomy: ↓ breast cancer risk by ~90%
- Oophorectomy:
- ↓ ovarian cancer risk (~95%)
- ↓ breast cancer risk (~50%)
Summary – Breast Cancers
Breast cancers commonly arise from ductal epithelium and are influenced by hormonal, genetic, and environmental risk factors. Early detection via screening and triple assessment is crucial. Management depends on staging and receptor status, involving surgery, chemotherapy, hormonal, and targeted therapies. For a broader context, see our Reproductive Health Overview page.