Breast disease encompasses a broad spectrum of conditions ranging from benign lumps to malignant tumours. Breast cancer is the most common cancer in women worldwide, arising most frequently from the ductal epithelium (invasive ductal carcinoma) or lobular tissue (invasive lobular carcinoma). Established risk factors include increasing age, female sex, BRCA1/BRCA2 gene mutations, positive family history, early menarche, late menopause, nulliparity, hormone replacement therapy, obesity and alcohol use. Benign breast diseases including fibroadenoma (the most common benign lump in young women), fibrocystic change, breast abscess, duct ectasia and fat necrosis must be carefully distinguished from malignancy through the triple assessment protocol.
Symptoms
A painless, firm, irregular lump with poorly defined margins is the classic presentation of breast cancer, though any new breast lump warrants urgent evaluation. Associated features suggesting malignancy include skin changes, peau d'orange (orange-peel skin texture due to lymphatic infiltration), skin tethering or dimpling nipple changes such as inversion, bloody or blood-stained nipple discharge and axillary lymphadenopathy indicating nodal spread. Breast pain (mastalgia) is more commonly associated with benign cyclical disease than malignancy. Paget's disease of the nipple, a specialised form of breast cancer presents as persistent eczema-like changes of the nipple-areolar complex. Inflammatory breast cancer presents with rapid onset breast swelling, redness, warmth and skin thickening, mimicking infection but representing an aggressive malignancy.
Diagnosis
All patients with a breast lump are assessed via the Triple Assessment, the cornerstone of breast disease evaluation:
Clinical examination: assessing lump characteristics, skin changes, nipple and axillary nodes
Imaging: Mammography is first-line in women over 35; Ultrasound is preferred in younger women with denser breast tissue and for characterising lesions identified on mammogram
Tissue sampling: Core needle biopsy under ultrasound guidance provides histological diagnosis, hormone receptor status (ER, PR) and HER2 status critical for guiding systemic therapy decisions
MRI breast is used selectively for pre-operative staging in lobular cancers, BRCA carriers and when mammogram and ultrasound are discordant.
Treatment
Treatment is multimodal and tailored to tumour stage, histology, receptor status and patient fitness. Surgery forms the cornerstone, Wide Local Excision (WLE) with sentinel lymph node biopsy is the preferred breast-conserving approach for early-stage tumours, followed by radiotherapy to the remaining breast tissue. Mastectomy with or without immediate reconstruction is performed for larger, multifocal or locally advanced tumours. Axillary node clearance is performed when sentinel node biopsy confirms nodal involvement. Adjuvant systemic therapy is tailored to receptor status: hormone receptor-positive tumours receive endocrine therapy (tamoxifen or aromatase inhibitors); HER2-positive tumours receive targeted therapy with trastuzumab (Herceptin); triple-negative breast cancer is treated with chemotherapy. Neoadjuvant chemotherapy is administered before surgery in locally advanced disease to downstage the tumour and improve surgical options. Early-stage breast cancer treated with surgery and adjuvant therapy carries an excellent prognosis, with 5-year survival exceeding 90% for Stage I disease.