Should a 32-year-old female with a large breast mass known to be a Phyllodes tumor be referred to an oncologist (oncology specialist)?

Management of Phyllodes Tumor: Oncology Referral Recommendation

Yes, a 32-year-old female with a large breast mass known to be a Phyllodes tumor should be referred to an oncologist, especially if the tumor is borderline or malignant subtype. 1

Classification and Risk Assessment

Phyllodes tumors are rare fibroepithelial lesions that account for less than 1% of all breast neoplasms. They are classified into three subtypes:

• Benign (approximately 58% of cases)
• Borderline (approximately 15% of cases)
• Malignant (approximately 26% of cases) 2

The classification is based on histological features including:

• Stromal cellularity
• Cellular atypia
• Mitotic activity
• Tumor margins
• Stromal overgrowth

Rationale for Oncology Referral

1. Multidisciplinary Management Required: Current guidelines recommend close collaboration between a breast cancer MDT and a sarcoma MDT for the management of patients with breast sarcomas and malignant phyllodes tumors 1

2. Risk of Recurrence: Local recurrence occurs in approximately 15% of patients and is more common after incomplete excision 3

3. Risk of Metastasis: Approximately 20% of patients with malignant phyllodes tumors develop distant metastases 3

4. Need for Specialized Treatment Planning:

   • For large malignant phyllodes tumors, breast conservation may not be possible
   • Adjuvant radiotherapy should be considered for:
     • Large tumors (>5 cm)
     • Close (<5 mm) or positive margins
     • Multifocal disease
     • Recurrent disease 1

Treatment Algorithm

1. Initial Surgical Management:

   • Wide excision with clear margins (ideally ≥1 cm) 1
   • Either breast conservative surgery or mastectomy depending on tumor size and breast size ratio 1
   • No axillary staging is required as lymph node metastases are rare 1

2. Post-Surgical Management:

   • Benign phyllodes: Routine follow-up if negative margins achieved
   • Borderline phyllodes: Consider adjuvant radiotherapy for high-risk cases (large tumors, infiltrative margins, close margins) 1
   • Malignant phyllodes: Consider adjuvant radiation treatment for large tumors (>5 cm), close (<5 mm) or positive margins, multifocal or recurrent disease 1

3. Recurrence Management:

   • Re-excision with wide margins
   • Consider postoperative radiation if not previously given 1
   • For metastatic disease, follow principles of soft tissue sarcoma management 1

Important Considerations

• Immediate reconstruction: Should be carefully discussed on an individual basis, as patients with large high-grade tumors may need postoperative chest wall radiotherapy and have significant risk of local recurrence within the first two years 1

• Delayed reconstruction: May be more appropriate after primary oncological management is completed and the risk of local recurrence has reduced 1

• Rapid growth potential: Phyllodes tumors can grow rapidly and become quite large, as seen in cases where tumors have caused "rupture" of the breast 4

Pitfalls to Avoid

1. Misdiagnosis as fibroadenoma: Phyllodes tumors can be mistaken for fibroadenomas, leading to inappropriate surgical management and increased risk of recurrence 3

2. Inadequate surgical margins: Narrow surgical margins are associated with heightened local recurrence risk 1

3. Unnecessary axillary dissection: Nodal metastases are rare, and routine axillary dissection is not recommended 3

4. Delayed referral: Given the potential for rapid growth and malignant behavior, prompt referral to an oncologist is crucial, especially for large tumors 4