Lumpectomy / Partial Mastectomy
What the Examiner Expects
Excision of a breast tumor with a rim of surrounding normal tissue, preserving the breast. Combined with whole-breast radiation, lumpectomy provides equivalent overall survival to mastectomy for early-stage breast cancer (NSABP B-06, 20-year follow-up). The examiner expects you to achieve negative margins (no ink on tumor per SSO-ASTRO guidelines for invasive cancer; 2 mm margins for DCIS). The specimen must be oriented (sutures or clips), sent for margin assessment, and if margins are positive, re-excision is required. Contraindications to breast conservation include multicentric disease, inability to achieve negative margins, prior radiation to the chest wall, and certain connective tissue disorders.
Key Examiner Focus Points
- Breast-conserving surgery: excision of tumor with negative margins (no tumor on ink)
- Must be followed by whole-breast radiation therapy
- Equivalent survival to mastectomy for stage I–II breast cancer (NSABP B-06)
- Contraindications: multicentric disease, prior chest wall radiation, positive margins after re-excision
- Specimen orientation and margin assessment are critical
Common Curveballs
Final pathology shows a positive deep margin
Re-excision of the deep (posterior) margin. If re-excision still yields positive margins, mastectomy is indicated. Do not accept positive margins — this increases local recurrence significantly.
Patient has a large tumor-to-breast ratio making cosmesis poor
Consider neoadjuvant chemotherapy to downstage the tumor and allow breast conservation. Alternatively, oncoplastic techniques (volume displacement with local tissue rearrangement) can improve cosmetic outcomes after large lumpectomies.
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