In a 60‑year‑old postmenopausal woman with a 2 cm grade II estrogen‑receptor‑positive, progesterone‑receptor‑negative, HER2‑negative invasive ductal carcinoma that is multicentric and a clinically palpable 2 cm axillary lymph node, does the presence of multicentric disease change the overall management plan?

Management of Multicentric Breast Cancer with Palpable Axillary Lymph Node

The presence of multicentric disease does NOT fundamentally change the overall management approach, but it does mandate mastectomy rather than breast-conserving surgery, while axillary staging and systemic therapy decisions remain driven by the clinically positive lymph node and tumor biology. 1

Surgical Management Changes

Mastectomy is required for multicentric disease. Multicentric tumors (distinct cancers in separate quadrants or >2-5 cm apart) are a contraindication to breast-conserving surgery. 1 The ESMO guidelines explicitly state that multicentricity contraindicates breast conservation, making mastectomy the standard surgical approach. 1

Axillary Management

The palpable 2 cm axillary lymph node is the critical factor determining axillary management, NOT the multicentric nature of the primary tumor.

• A clinically suspicious palpable axillary lymph node is a contraindication to sentinel lymph node biopsy alone. 1 This patient requires either:

  • Fine needle aspiration or core biopsy of the palpable node preoperatively to confirm metastasis
  • If positive, proceed directly to axillary lymph node dissection at the time of mastectomy 1

• The multicentric nature of the primary tumor does NOT preclude sentinel lymph node biopsy if the axilla were clinically negative. 1 Studies have shown that subareolar or intradermal injection techniques can successfully identify sentinel nodes in multicentric disease with comparable false-negative rates to unifocal disease. 1

Systemic Therapy Considerations

Systemic therapy decisions are driven by the tumor biology (ER+/PR-/HER2-) and the likely node-positive status, NOT by multicentricity. 2

• This 60-year-old postmenopausal woman with a 2 cm grade II, ER+/HER2- tumor and clinically positive node will require:
  • Adjuvant endocrine therapy (aromatase inhibitor preferred over tamoxifen in postmenopausal women) 2
  • Chemotherapy consideration based on final nodal burden and genomic testing if appropriate 2

Radiation Therapy

Post-mastectomy radiation therapy will be indicated based on the axillary nodal involvement, not the multicentric nature of the primary tumor. 1, 2

• If ≥4 positive nodes are found, post-mastectomy radiotherapy to the chest wall and regional nodes is strongly recommended 1, 2
• The multicentric primary does not independently influence radiation decisions 1

Key Clinical Pitfalls

Do not perform sentinel lymph node biopsy alone in the presence of a clinically suspicious palpable axillary node. 1 The ASCO guidelines explicitly list "suspicious palpable axillary lymph nodes" as a contraindication to sentinel node biopsy. 1

Do not deny breast conservation solely based on multicentricity discovered on final pathology if margins are clear and all disease was removed. 3 However, in this case with known preoperative multicentric disease, mastectomy is appropriate. 1

Multicentric disease is associated with higher rates of axillary metastasis (>90% in some series), particularly with lobular histology. 4 This reinforces the importance of thorough axillary staging in this patient. 4