A 52-year-old postmenopausal woman from Mumbai presents with a 2 cm hard, irregular mass in the upper outer quadrant of the left breast discovered on self-examination 3 weeks ago. Physical examination reveals a fixed mass, skin dimpling, and a single ipsilateral axillary lymph node (1.5 cm, firm, mobile). Mammography confirms a BIRADS 5 lesion. Core needle biopsy shows invasive ductal carcinoma with intermediate grade (Nottingham score 6/9). Staging investigations including chest X-ray, abdominal ultrasound, and bone scan are normal. The patient is counselled for surgery. Which of the following is the most appropriate surgical management?

Explanation

## Clinical Assessment **Key Point:** This patient has clinical stage IIA–IIB breast cancer (T2N1M0) with a 2 cm tumour and a single palpable axillary node. The fixed nature of the mass and skin dimpling indicate local advancement. ### Staging Summary | Feature | Finding | |---------|----------| | Tumour size | 2 cm (T2) | | Axillary node | Single, firm, mobile (N1) | | Distant metastases | None (M0) | | Grade | Intermediate (Nottingham 6/9) | | Stage | IIA–IIB | ## Rationale for Modified Radical Mastectomy (MRM) **High-Yield:** Modified radical mastectomy with complete axillary lymph node dissection (levels I–III) is the gold standard for: 1. **Tumours ≥2 cm** — exceeds the size threshold for breast-conserving therapy (typically ≤5 cm with adequate margins and no contraindications) 2. **Clinically involved axillary nodes** — palpable nodes mandate formal axillary dissection, not sentinel node biopsy alone 3. **Skin involvement** (dimpling) — indicates deeper invasion and loss of candidacy for BCT 4. **Prognostic staging** — complete level I–III dissection provides accurate nodal staging (essential for adjuvant therapy decisions) **Clinical Pearl:** Sentinel lymph node biopsy is appropriate only for clinically node-negative disease. Once a node is palpable and suspicious, axillary dissection is mandatory to: - Assess the number and level of involved nodes (prognostic) - Provide regional control - Guide chemotherapy decisions ### MRM Components - Removal of breast, nipple–areola complex, and axillary tail - Preservation of pectoralis major and minor muscles - Axillary dissection levels I, II, and III **Mnemonic: BCT Contraindications — "PRISM"** - **P**regnancy (relative) - **R**adiation history to breast - **I**nadequate margins achievable - **S**kin involvement / Satellite nodules - **M**ultifocal disease This patient has skin involvement (dimpling) and clinically positive nodes — both absolute contraindications to BCT. ## Why MRM Over Other Options **Comparison with Alternatives:** | Procedure | Indication | Why Not Here? | |-----------|-----------|---------------| | BCT + SLNB | T1–T2, N0, no skin involvement | Skin dimpling + palpable node contraindicate BCT | | Simple mastectomy + SLNB | Prophylactic, DCIS, high-risk | Does not address clinically involved axilla; inadequate staging | | Mastectomy + Level I only | Not standard | Incomplete staging; misses level II/III disease in 15–20% of N1 cases | [cite:Robbins 10e Ch 24], [cite:Harrison 21e Ch 342]