What is the recommended management for Phyllodes tumors?

Management of Phyllodes Tumors

Wide local excision with at least 1 cm margins is the standard treatment for all phyllodes tumors, with adjuvant radiation therapy strongly recommended for borderline and malignant subtypes to reduce local recurrence risk. 1

Etiology and Pathophysiology

Phyllodes tumors are rare fibroepithelial neoplasms of the breast that account for less than 0.5% of all breast tumors. They are characterized by:

• Biphasic growth pattern with both stromal and epithelial components
• Leaf-like projections into cystic spaces
• Variable stromal cellularity and atypia

Classification

Phyllodes tumors are classified into three categories based on histopathological features:

1. Benign (approximately 60-70% of cases)

   • Minimal stromal cellularity and atypia
   • Low mitotic activity
   • Pushing margins

2. Borderline (approximately 20% of cases)

   • Moderate stromal cellularity and atypia
   • Intermediate mitotic activity
   • Infiltrative or pushing margins

3. Malignant (approximately 10-15% of cases)

   • Marked stromal hypercellularity and atypia
   • High mitotic activity
   • Infiltrative margins
   • Stromal overgrowth

Clinical Presentation and Diagnosis

• Palpable breast mass
• Rapid growth pattern
• Often large size (>2 cm)
• Ultrasound findings similar to fibroadenoma but with larger size or growth history 2

Diagnostic workup includes:

• History and physical examination
• Ultrasound
• Mammogram for women ≥30 years
• Core needle biopsy (though it may not reliably distinguish phyllodes from fibroadenoma) 2

Management Algorithm

Primary Surgical Management

1. Benign Phyllodes

   • Wide local excision with ≥1 cm margins 2, 1
   • Re-excision if margins are positive or narrow (<1 cm)
   • No axillary staging required

2. Borderline Phyllodes

   • Wide local excision with ≥1 cm margins 2, 1
   • Mastectomy if negative margins cannot be achieved with breast conservation
   • Consider adjuvant radiation for high-risk features (large tumors, infiltrative margins)

3. Malignant Phyllodes

   • Wide local excision with ≥1 cm margins or mastectomy for large tumors 2, 1
   • No axillary staging required (lymph node involvement is rare)
   • Adjuvant radiation therapy strongly recommended 3

Adjuvant Therapy

1. Radiation Therapy

   • Strongly recommended for all malignant phyllodes tumors 2, 1
   • Consider for borderline phyllodes with high-risk features
   • Indications include:
     • Large tumors (>5 cm)
     • Close (<5 mm) or positive margins
     • Infiltrative margins
     • Multifocal or recurrent disease
   • Significantly improves local recurrence-free survival (90% vs 42% at 5 years) 3

2. Chemotherapy

   • No established role in primary management
   • For metastatic disease, follow soft tissue sarcoma protocols 2

3. Endocrine Therapy

   • No established role despite ER/PR expression in epithelial component 1

Management of Recurrence

1. Local Recurrence

   • Re-excision with wide margins without axillary staging 2
   • Consider postoperative radiation if not previously administered 2
   • Mastectomy for extensive recurrence

2. Metastatic Disease

   • Manage according to soft tissue sarcoma principles 2

Important Considerations and Pitfalls

1. Surgical Margins

   • Narrow margins (<1 cm) significantly increase local recurrence risk 4
   • 90% of recurrences occur in patients who underwent simple lumpectomy without adequate margins 5
   • Achieving negative margins is the most important factor for local control

2. Reconstruction Timing

   • Consider delayed rather than immediate reconstruction for large malignant tumors that may require postoperative radiation 2

3. Diagnostic Challenges

   • Core needle biopsy and FNA often inadequate to distinguish phyllodes tumors from fibroadenomas 2, 1
   • Clinical suspicion should be high for rapidly growing or large fibroepithelial lesions

4. Recurrence Patterns

   • Most recurrences occur within the first few years after treatment 1
   • Regular surveillance is essential, particularly for borderline and malignant subtypes

5. Unpredictable Behavior

   • Histologic classification does not always reliably predict clinical behavior 6
   • Even benign phyllodes tumors can recur if inadequately excised

The management of phyllodes tumors requires a multidisciplinary approach with careful pathologic evaluation and appropriate surgical planning to minimize recurrence risk while optimizing cosmetic outcomes.