A 58-year-old woman from Delhi undergoes screening mammography and is found to have a 2.5 cm mass in the upper outer quadrant of the left breast with microcalcifications. Core needle biopsy confirms invasive ductal carcinoma, grade 2, ER/PR positive, HER2 negative. Staging CT shows no distant metastasis. Sentinel lymph node biopsy is negative (pN0). The tumour is clinically mobile with no skin involvement or nipple retraction. What is the most appropriate surgical management?

Explanation

## Breast-Conserving Therapy vs Mastectomy in Early Breast Cancer ### Patient Profile & Staging **Key Point:** This patient has early-stage breast cancer (T2N0M0, Stage IIA) with negative sentinel lymph nodes. She is an ideal candidate for breast-conserving therapy (BCT), which offers equivalent survival to mastectomy with superior cosmetic outcomes. ### Criteria for Breast-Conserving Therapy (BCT) | Criterion | Status in This Patient | | --- | --- | | **Tumour size** | 2.5 cm (T2) — acceptable for BCT | | **Tumour location** | Upper outer quadrant — permits adequate margin | | **Lymph node status** | pN0 (sentinel node negative) — favourable | | **Distant metastasis** | M0 — no metastasis | | **Skin involvement** | None — no contraindication | | **Nipple involvement** | None — no contraindication | | **Pregnancy status** | Not mentioned; assume non-pregnant (radiotherapy feasible) | | **Prior breast radiotherapy** | Not mentioned; assume none | | **Ability to receive radiotherapy** | Assumed yes (no contraindication stated) | **High-Yield:** BCT consists of: (1) wide local excision with adequate margin (1–2 cm), (2) whole-breast radiotherapy (50 Gy in 25 fractions over 5 weeks), and (3) systemic therapy (endocrine ± chemotherapy based on risk factors). BCT achieves 5-year and 10-year survival equivalent to mastectomy [cite:Harrison 21e Ch 374]. ### Why BCT is Preferred Here 1. **Tumour size:** 2.5 cm is well within the range for BCT; tumours up to 5 cm can be treated with BCT if adequate margin is achievable. 2. **Negative sentinel nodes:** pN0 status indicates low risk of axillary recurrence; formal axillary dissection is not needed. 3. **Cosmetic advantage:** BCT preserves breast tissue and offers superior cosmetic outcome compared to mastectomy. 4. **Equivalent survival:** Landmark trials (NSABP B-06, EORTC 10801) demonstrated that BCT + radiotherapy achieves survival equivalent to mastectomy for early-stage disease [cite:Robbins 10e Ch 24]. 5. **Systemic therapy:** Adjuvant endocrine therapy (tamoxifen or aromatase inhibitor) is indicated for ER/PR-positive disease; chemotherapy may be considered based on additional prognostic factors (grade, Ki-67, age). **Clinical Pearl:** Whole-breast radiotherapy is MANDATORY after BCT to reduce local recurrence risk from ~20% to <5%. Omission of radiotherapy negates the survival equivalence with mastectomy. **Mnemonic:** **BCTA** — Breast-Conserving Therapy Algorithm: - **B**reast size adequate for margin - **C**lear margin achievable (1–2 cm) - **T**umour size ≤5 cm (ideally ≤4 cm) - **A**djuvant radiotherapy planned