Breast Surgery
The breast domain tests triple assessment, the benign/malignant distinction, staging, and the modern axillary algorithm. Expect questions on when to biopsy, when to perform sentinel node biopsy, and what neoadjuvant therapy changes.
Assessment
- Triple assessment: clinical examination, imaging (ultrasound under 40 years; mammography with ultrasound at 40 and over), and pathology - core needle biopsy preferred over FNA.
- BI-RADS guides action: 2 benign, 3 probably benign with six-month follow-up, 4 suspicious requiring biopsy, 5 highly suggestive of malignancy.
- Fibroadenoma: well-defined, mobile, confirmed on core biopsy, no surgery needed. Phyllodes tumour: rapid large mass, leaf-like histology, excised with wide margins.
Cancer
- Histology: invasive ductal (no special type) is commonest; lobular, DCIS, and Paget's disease of the nipple (eczematous nipple with underlying DCIS) also appear.
- Receptors: ER, PR, HER2 and Ki-67 determine systemic treatment; triple-negative disease is aggressive.
- Surgery: breast-conserving surgery plus radiotherapy is equivalent to mastectomy for most early cancers; mastectomy for multicentric disease, poor tumour-to-breast ratio, or inflammatory cancer after neoadjuvant therapy.
- Axilla: sentinel node biopsy for clinically node-negative disease; the ACOSOG Z0011 trial allows omission of axillary dissection in selected patients with one or two positive sentinel nodes treated by conservation and whole-breast radiotherapy.
- Neoadjuvant chemotherapy for locally advanced, HER2-positive or triple-negative tumours; it downstages and measures response.
- Inflammatory carcinoma: erythema and peau d'orange - not an indication for immediate surgery.
Worked example
A 48-year-old has a 2.5 cm upper outer quadrant mass; core biopsy shows grade 2 invasive ductal carcinoma, ER-positive, HER2-negative, clinically node-negative. Reasoning: no MRI is required; ultrasound the axilla to confirm N0, then offer breast-conserving surgery with sentinel node biopsy, whole-breast radiotherapy and endocrine therapy. Axillary dissection only if the sentinel node is positive outside Z0011 criteria.
Traps
- Doing an excisional biopsy first - it compromises margins and sentinel node mapping.
- Using FNA for a suspected phyllodes tumour; core biopsy is needed.
- Failing to image the axilla before surgery.
- Accepting a normal mammogram as exclusion of cancer in a dense breast with a palpable lump.