Breast cancer is the most common type of cancer in the UK, affecting 1 in 8 women (it is rare in men, who make up about 1% of all breast cancer diagnosis).
Anatomy of the breast
Breast is made up of mammary glands, skin, connective tissue. It extends from the 2nd ICS to the 6th rib generally, where it forms the inframammary fold.
Laterally, it has a tail of Spence that extends into the axillary region.
Mammary glands are specialised tissue made up of lactiferous ducts and lactiferous tubules that are held in place by suspensory ligaments (Cooper’s ligaments).
The secretory lobes contain the alveoli (10-100 of them) which lead into the intralobular duct → lactiferous ducts → lactiferous sinus → nipple.
A non-lactating breast is made up of more adipose tissue than mammary glands. During lactation, it grows significantly.
Males don’t have much breast tissue, but they do have some and are still at risk for breast cancer. It does grow with increased oestrogen levels (gynaecomastia).
There are 4 main types of breast cancers:
1. Ductal Carcinoma in Situ (DCIS)
The most common form of non-invasive breast cancer. It is a malignancy in the ductal tissue that is contained within the basement membrane of the ducts. The grade is considered higher as the ductal cells lose their acinar structure and their nuclei become abnormally large.
It is often detected during screening through microcalcifications seen on mammograms.
2. Lobular Carcinoma in Situ (LCIS)
A non-invasive carcinoma of the secretory lobules that is also contained within the the basement membrane of the lobe. It is rarer than DCIS but has a higher risk of becoming malignant than DCIS. It mainly occurs in pre-menopausal women. Abnormal proliferation of lobular cells arrange themselves in single rows. The cells are often small, bland and uniform.
Also asymptomatic and detected during screening mostly.
3. Invasive Ductal Carcinoma (IDC)
Makes up around 70-80% of invasive breast cancers. It also originates in the ducts of the breast. The combination of irregular, hard lump which is fixed to the deep tissue (such as the pectoralis major muscle) is very suspicious for invasive breast cancer.
4. Invasive Lobular Carcinoma (ILC)
It is the 2nd most common malignant breast cancer. The tumour cells originate in the breast lobules. It is more common in older woman
⚠️ Risk factors
- Female
- Increasing age - risk doubles every 10 years until menopause.
- Oestrogen exposure also increases risk. Therefore nulliparous women are at greater risk along with long term HRT usage (>5 years).
- Family history - BRCA1 and BRCA2 are the most common breast cancer associated mutations.
- Primary care criteria for referral for patients at higher risk due to family history:
- 1º relative with breast cancer <40 years
- 1º male relative with breast cancer
- 1º relative with bilateral breast cancer <50 years old
- 2 x 1º relative with breast cancer
Ovarian cancer is also a relevant family history.
These patients may require genetic counselling at a specialist genetic clinic or may be seen in a secondary care breast clinic.
- Obesity - in postmenopausal women as aromatase increases. In premenopausal women it decreases risk potentially as oestrogen increases by aromatase interfere with FSH and LH release.
- Alcohol
- Smoking
😷 Presentation
Patients may be symptomatic, but often may be asymptomatic and present during screening only.
Some presentations may be:
- Breast/axillary lumps - these lumps may be hard, craggy and tethered to the underlying skin.
- Breast asymmetry
- Swelling
- Discharge
- Comedo necrosis - a feature of high nuclear grade ductal carcinoma in situ.
- Nipple inversion (that was not previously present) - due to shortening of the mammary ducts.
- Skin changes - such as dimpling (due to retraction of Cooper’s ligaments), erythema, peau d’Orange (due to obstruction of lymphatic drainage)
- Mastalgia
🔍 Investigations
🏆 The gold standard for for diagnosis is the triple assessment this is due to sensitivity of each individual component, so we act as a filter, increasing sensitivity with each step.
- History and examination - full detailed history and examination of the breast and axillary regions.
- Imaging
- USS in women <35 due to the density of the breast tissue and reduced exposure to radiaton
- Mammogram in women >35, looking for microcalcifications and mass lesions of the breast. Better for ductal carcinomas than lobular carcinomas.
- MRI is not routinely used but can be useful for lobular breast cancer (ILC and LCIS) as these are not detectable on mammogram. Specificity is not good with MRI, however.
- Biopsy - histology may be done using core biopsy rather than fine-needle aspiration as it can differentiate between invasive and in-situ carcinomas.
- FNA involves aspiration using a very thin needle while feeling the tumour or using US guidance.
- Core biopsy are done with much larger needles and requires local anaesthesia, but provides a better, larger sample for biopsy.
An MDT discussion will be needed once a diagnosis has been made in order to manage the patient best. Sentinel node biopsy may be done during breast surgery. It is done by injecting an isotope contrast of blue dye into the tumour area which travel from the lymphatics to the sentinel node (shows up blue on the isotope scanner). A biopsy will then be done of this lymph node.
At each stage of triple assessment, we can calculate a probability score of it being benign or malignant:
🧰 Management
Treatment involves surgery, radiotherapy, chemotherapy, hormonal therapy, antibody therapy. It all depends on the individual factors of the patient and tumour.
- Tamoxifen - is used in pre and peri-menopausal women who are ER+. It is a SERM that is an agonist in bone and uterus but antagonist in breast and prostate.
- Adverse effects: increased risk of endometrial cancer, VTE, and menopausal symptoms.
- Anastrozole (and other aromatase inhibitors) - are offered to post-menopausal women who are ER+. Aromatase converts androgens (such as testosterone) to oestrogen. This is more common in post-menopausal women and so aromatase inhibitors are more effective in this demographic of patients. Due to the risks of osteoporosis, bone mineral density should be measured both prior to treatment and regularly throughout treatment.
- Adverse effects: osteoporosis, joint pain, hot flushes.
- Trastuzumab (HERceptin) - is used for HER2+ patients. HER2 is upregulated with tamoxifen use. It works by binding to segment IV on the HER2 receptor, thus preventing homodmerization of the receptor.
- Adverse effects: heart failure.
- Pertuzumab (Perjeta) - binds to segment II on the HER2 receptor.
- FEC-D is used in patients with axillary node involvement:
- 5-Fluorouracil
- Epirubicin
- Cyclophosphamide
- Docetaxel
🛣 Prognosis
Prognosis depends on nodal involvement, size, grade and receptor status.
The Nottingham Prognostic Index is used as the staging system for breast cancer prognosis:
- Size - refers to the diameter of the tumour in cm.
- Nodes
- 0 nodes = 1
- 1-4 nodes = 2
- >4 nodes = 3
- Grade - based on the Bloom-Richardson classification.
👀 Screening and referral
Women aged 50-70 are offered a mammogram every 3 years. After 70 years old they will be encouraged to make their own appointments
Referral for breast cancer is done using the 2 week suspected cancer pathway if:
- 30 years old+ with an unexplained lump
- 50 years old+ with unilateral nipple discharge, retraction or any other changes that are noticeable.
2ww referral may also be done in individuals with skin changes suggestive of breast cancer or 30y/o+ with an axillary lump.
🚨 Metastasis
The 2 L’s and 2 B’s:
L - Liver
L - Lungs
B - Bones
B - Brain
🚨 Lymphoedema
Chronic lymphoedema may be present in the entire arm after surgery that has had axillary lymph node removal. These areas are more prone to infection. Patients may be referred to special lymphoedema services to aid drainage and care of these areas.
One should not take bloods or put a cannula in the side where axillary lymph nodes were removed as this increases the risk of complications.
Paget’s disease is when we have eczematous changes to the nipple (although is different to eczema of the nipple). In almost 90% of cases this is due to an underlying neoplasm. It is present in 1-2% of breast cancer patients.
The difference between Paget’s and eczema of the nipple is that it primarily involves the nipple and spreads to the areola. In eczema of the nipple the areola is the primary source and it spreads to the nipple.
😷 Presentation
- Itching
- Redness
- Flaking/thickening of skin on or around the nipple
- Pain and sensitivity
- Yellowish/bloody discharge
🔍 Investigations
Biopsy is needed for confirmation of diagnosis.
Breast examination is also required.
Imaging may be warranted (mammogram/USS or MRI).
🧰 Management
Dependent on the underlying cause but surgery is indicated often. The extent of the surgery depends on the cancer but almost always the nipple and areola are removed.
IBC occurs when there is a blockage of lymphatic drainage of the breast due to cancerous cells blocking it. It is refractory to antibiotics and will present with a peau d’Orange appearance, that is warm and tender. It is generally worse than other breast cancers.
It makes up 1-3% of breast cancers (1 in 10,000 supposedly).