What are the principles of resection for a patient with a soft tissue tumor of the breast?

Principles of Resection for Soft Tissue Tumors of the Breast

The primary surgical principle is wide excision with clear (negative) margins, achieved through either breast-conserving surgery or mastectomy, with the critical goal of obtaining tumor-free margins to minimize local recurrence and optimize survival. 1

Core Surgical Principles

Margin Requirements

• Achieve negative histopathological margins as the paramount objective for local control 1
• Target margins of ≥1 cm when feasible to minimize local recurrence risk 2
• For inadvertent excisions with positive margins but no macroscopic residual disease, conservative re-excision with primary closure is acceptable 1
• If clear margins cannot be achieved surgically after re-excision attempts, adjuvant radiotherapy should be considered to improve local control 1

Surgical Approach Selection

• Either breast-conserving surgery (BCS) or mastectomy can be performed based on tumor size relative to breast size and ability to achieve clear margins 1, 3
• For large malignant phyllodes tumors or aggressive primary breast sarcomas, breast conservation may not be possible 1
• Mastectomy is indicated only when adequate margins cannot be achieved with breast conservation 2, 4

Critical Technical Considerations

• Do NOT perform axillary staging by sentinel node biopsy or axillary lymph node dissection - this is unnecessary and adds morbidity, as breast sarcomas rarely metastasize to lymph nodes (<1% have positive nodes) 3, 2, 4
• This distinguishes sarcoma management from epithelial breast cancer, where nodal staging is routine 3
• Use separate incisions for primary tumor removal and any axillary procedures if anatomically necessary 5

Reconstruction Timing

Delayed reconstruction is strongly preferred over immediate reconstruction in high-risk cases 1, 2

• For large high-grade tumors or malignant phyllodes tumors, patients are likely to receive postoperative chest wall radiotherapy 1
• These tumors carry significant risk of local recurrence within the first two years after diagnosis 1
• Delayed reconstruction should be performed when primary oncological management is completed and local recurrence risk has diminished (typically after 2 years) 1, 2
• Immediate reconstruction should be avoided in borderline phyllodes tumors with high-risk features 2

Adjuvant Radiotherapy Indications

Adjuvant radiotherapy improves local control but not survival in breast sarcomas 1, 3

Specific Indications:

• Large tumors (>5 cm) 1, 4, 6
• Close margins (<5 mm) or positive margins 1, 2
• Multifocal disease 1
• Recurrent disease 1
• Infiltrative margins, especially in borderline phyllodes tumors 1, 2
• These indications apply regardless of surgery type (BCS versus mastectomy) 1

Borderline Phyllodes Specific:

• In borderline phyllodes tumors, surgical excision alone is likely curative if negative margins are achieved 1
• Adjuvant radiotherapy should be considered only in high-risk cases: large tumors, infiltrative margins, or when clear margins could not be achieved surgically 1, 2

Multidisciplinary Management Requirements

All breast sarcomas and malignant/borderline phyllodes tumors must be referred to specialist sarcoma centers for pathology review and multidisciplinary team (MDT) discussion 1, 3, 4

• Close collaboration between breast cancer MDT and sarcoma MDT is necessary 1, 2
• This ensures appropriate risk stratification and treatment planning 2
• Surgery should be undertaken by a surgeon experienced in managing these diseases 1

Special Considerations by Histologic Subtype

Radiation-Induced Angiosarcoma:

• Has aggressive biology with high risk of both local and distant relapse 1
• Pre-operative communication between breast and sarcoma MDT is paramount 1
• Consider resurfacing plastic surgical procedures to gain wide margins if necessary 1
• Induction chemotherapy should be considered in locally advanced disease where surgery would be excessively morbid or oncologically futile 1

Dermatofibrosarcoma Protuberans (DFSP):

• Has infiltrative growth pattern with potential for wide and deep extension from deep dermis into subcutaneous fat 1
• Wide surgical margins are advocated to account for local recurrence risk 1
• Gaining negative histopathological margins is paramount for local control 1

Common Pitfalls to Avoid

• Never perform axillary staging - it is unnecessary and adds morbidity in sarcomas 3, 2, 4
• Do not use breast cancer chemotherapy regimens for phyllodes tumors or sarcomas; use sarcoma-directed protocols if systemic therapy is needed 4
• Avoid immediate reconstruction in high-risk malignant tumors that will require postoperative radiotherapy 1, 2
• Do not treat sarcomatous differentiation within metaplastic carcinoma as sarcoma - these should be managed as epithelial breast cancer 1
• When performing open biopsy with suspicion of carcinoma, the procedure should effectively be a lumpectomy using wide local excision with a cuff of tumor-free tissue 5