Breast Cancer

“Uncontrolled cell growth in the breast”

Two main types of breast cancer:
- Ductal carcinoma in-situ (DCIS) (90%)
- Lobular carcinoma in-situ (LCIS) (10%).

Breasts are made up of three parts – glandular tissue, stroma and lymphatic vessels.
- Glandular tissue contains hormonal receptors e.g. oestrogen (ER), progesterone (PR), which stimulate the alveolar cells to divide
- Each menstruation cycle causes a division of cells following by apoptosis
- Every time cells divide, the risk of genetic mutations increase and thus increase the chance of tumour growth
- If a mutation occurs, the affected cell (usually epithelial) will undergo uncontrollable division to form the tumour in the BM of the alveoli.

DCIS: tumour grows from wall to lumen. Can cross the BM to form an invasive ductal carcinoma.
- Can lead to Paget’s Disease of the Nipple.
LCIS: clusters of tumour cells in the lobule, do not invade the ducts.
Some of the tumours also have hormonal receptors: ER+&HER2- (most common), HER2+/ER+/-, ER-/HER2+

Local disease:
- Breast mass – hard, painful, swelling
- Nipple changes – itching, redness, crusting, discharge – Paget’s disease
- Swelling under armpit – spread to axillary lymph nodes
- Breast immobile/fixed – infiltration if cancer cells spread to pectoral muscles
- Dimpling of skins – involvement of skin
- Non-specific symptoms – weight loss, loss of appetite, fatigue

Metastatic:
- Shortness of Breath – lung metastases, pleural effusion
- Headaches/change of vision
- Seizures – brain metastases
- Abdominal pain – liver metastases
- Bone pain/weakness/numbness – spinal cord compression

Triple assessment: clinical examination, radiology, histology/cytology:
- Mammogram, ultrasound of breasts (with/without MRI for younger patients)
- Core biopsy of breast lesion/distant metastatic site
- CT chest, abdomen, pelvis & bone scan for staging (if lymph nodes are present)

Surgery:
- Removal of the tumour by wide local excision (WLE) or mastectomy +/- axillary node sampling
Radiotherapy:
- Recommended for all patients after WLE.
- Axillary radiotherapy used if lymph node +ve.
Chemotherapy:
- Considered if high-grade, HER2+, triply negative, node +ve, large tumour (e.g. epirubicin and CMF (cyclophosphamide, methotrexate, 5-FU).
Endocrine agents:
- To decrease oestrogen activity, used in ER+ or PR+ (e.g. tamoxifen).
- Aromatase inhibitors (e.g. anastrozole) only used if post-menopausal

Inflammation leading to fibrosis, Invasion of nearby tissue (e.g. muscles, skin), entrance and blockage of lymphatic vessels (→ Peau D’orange appearance), tumour spreading via blood and lymph to other tissues