Breast Cancer

"A 35 Year old women presents with a 1cm hard lump in the upper quadrant of her right breast. She first noticed this when she was in the shower three months ago. She is worried that the lump might be malignant"

Overview

Overview Breast cancer is the most common cancer in women worldwide. It accounts for about 25% of all female malignancies, with a higher proportion in developed country. Despite the increasing incidence of breast cancer, death rates are falling owing to earlier diagnosis, better surgical and radiotherapy techniques, and improved systemic therapies.

• Lifetime risk for women 9%
• Commonest in Western Europe
• Least common in Japan and Africa

Breast Anatomy and Physiology

The breast is a subcutaneous structure composed of 15 to 20 lobes of mammary gland tissue and fat and typically extends into the axilla as the axillary tail. The ligaments of Cooper (fibrous septa running from the subcutaneous tissue to the fascia of the chest wall) separates the breast lobules. The nipple is surrounded by the pigmented areola. Each lobule drains by its lactiferous duct on to the nipple.

Boundaries and Borders

• The female breast lies over the 2nd - 6th rib
• Two-thirds of it rests on pectoralis major
• One-third of it lies on the serratus anterior
• The lower medial edge of the breast overlaps the upper part of the rectus sheath

Blood supply

• Internal thoracic artery → Internal mammary artery
• Subclavian artery → Axillary artery → Lateral thoracic artery → Lateral mammary artery
• Subclavian artery → Axillary artery → Lateral thoracic artery → Acromiothoracic artery
• Intercostal arteries → lateral perforating branches

Lymphatic drainage

• Majority of lymph drained from the breast (75%) → axillary lymph nodes
• Medial quadrants of the breast → parasternal lymph nodes along the internal thoracic vessels
• Inferior quadrants (some lymph) → inferior phrenic nodes

Physiology - normal breast changes in women

• Puberty - ↑Oestrogen → promotes the development of the mammary ducts and fatty tissue in breast.
• Menstrual cycle - Second half of menstrual cycle (after ovulation). ↑Oestrogen and ↑Progesterone → tender and swollen.
• Pregnancy - ↑Oestrogen and ↑Progesterone (placental oestrogen and progesterone) + ↑Prolactin → preparation for milk production
  • Women taking HRT get breast tenderness
• Postnatal - ↓Oestrogen and ↓Progesterone and ↑Prolactin → Stimulate the alveoli and milk production
  • Suckling on breast by baby stimulates oxytocin release which stimulates myoepitheliual cell of the breast to contract ejecting milk to baby's mouth.
• Menopause - ↓Oestrogen → breast become softer, homogenous and atrophy.

Risk Factors

Signs and Symptoms

General presentation

• Breast lump (usually painless)
• Screen-detected
• Bone pain
• Anaemia

Examination

Breast lump

• Hard and gritty
• Immobile (within breast tissue), tethered (attached to surrounding breast tissue) or fixed (attached to chest wall)
• Ill defined - irregular boarders

Skin changes

• Dimpling or puckering
• Peau d'orange - lymphoedema of skin
• Inflammation
• Late presentation: ulcerating or fungating

Nipple changes

• Destroyed
• Inverted
• Deviated
• Associated with bloody discharge

Differential Diagnosis

More info on Breast Lumps

Investigations

General

• Ultrasound - to differentiate between cystic and solid
• MRI
• Mammography
• Genetic screening
• Needle aspiration and cytology - For impalpable lesions, stereotactic techniques can be used to localise the lesion for needle aspiration.
• Wide bore core needle biopsy - provides a sample of tissue for histological rather than cytological examination

Diagnosis - Triple assessment

1. Clinical Examination
2. Imaging (mammogram, ultrasound, MRI)
3. Pathology - fine needle aspiration/biopsy

Staging - TNM classification

Pathology

Most carcinomas originate as in situ carcinoma before becoming invasive

• Ductal adenocarcinoma in situ -> Invasive Ductal Adenocarcinoma (80%)
• Lobular adenocarcinoma in situ -> Invasive Lobular Adenocarcinoma (20%)
• Other Invasive breast tumours:
  • Paget's Disease
  • Tubular Adenocarcinoma
  • Medullary Adenocarcinoma
  • Inflammatory
  • Sarcoma (rare)
  • Lymphoma (rare)

Classifcation

Carcinoma in situ Carcinoma in situ (CIS) refers to the period during which normal epithelial cells undergo apparent malignant transformation but do not invade through the basement membrane. There are two forms:

• Lobular Carcinoma in Situ
• Ductal Carcinoma in Situ Classification (more common)
  • Comedo
  • Non-comedo
    • Cribriform
    • Micropapillary
    • Papillary
    • Solid
    • Clinging

Pathophysiology

Management

Medical Treatment

• Endocrine (aim to reduce estrogen levels) - Tamoxifen, aromatase inhibitors, GnRH analogues
• Chemotherapy
• Radiotherapy - Is indicated following breast conservation surgery, and reduced the risk of local recurrence.

Surgical Treatment (usually in conjunction with chemotherapy +/- radiation)

• Partial Masectomy
  • Wide local excision
• Total Mastectomy
  • Simple
  • Skin sparing
  • Radical
• Surgical excision of lymph node
• Sentinel Lymph node biopsy - results in fewer arm complications compared with axillary lymph node dissection in the treatment of breast cancer

Complications and Prognosis

Medication Complication

• Tamoxifen induced endometrial cancer
• Tamoxifen related DVT
• Tamoxifen related PE
• Aromatase induced osteopenia/osteoporosis
• Menopausal symptoms

Radiotherapy Complication

• Redness and soreness of the field of radiation
• Lymphoedema after treatment of the axilla
• Breast‐feeding from the affected breast is unlikely
• Cardiac damage following left breast irradiation
• Brachial plexus palsy
• Osteitis of the ribs
• Shoulder stiffness
• Pulmonary fibrosis

Chemotherapy Complication

• Nausea/vomiting
• Neutropenia/neutropenic fever
• Leukaemia
• Ovarian failure

Surgery Complication

• Lymphedema
• Breast haematoma
• Wound infection
• Seroma of the skin flap
• Pscyhological effects on body image

Prognosis

Prevention

The early detection methods are:

• Breast awareness – awareness by a woman of the normal look and feel of her breasts
• Clinical breast examination – physical examination of an asymptomatic woman’s breasts by a medical or allied health professional
• Screening mammography – use of mammography in asymptomatic women to detect breast cancer at an early stage (BreastScreen Australia is the national mammographic screening program).

It is recommended that women aged 50–69 years attend the BreastScreen Australia Program every 2 years for screening mammograms.

References

Best Practice