What is the management approach for a patient with a benign, borderline, or malignant phyllodes tumor?

Management of Phyllodes Tumors

All phyllodes tumors—whether benign, borderline, or malignant—require surgical excision with tumor-free margins of at least 1 cm, without axillary staging, and neither chemotherapy nor endocrine therapy has any role in treatment. 1, 2

Surgical Management Algorithm

Primary Treatment for All Subtypes

• Wide local excision (lumpectomy/partial mastectomy) is the preferred surgical approach for benign, borderline, and malignant phyllodes tumors 3, 1, 2
• The critical goal is achieving surgical margins ≥1 cm, which is the single most important factor for preventing local recurrence—more important than histologic subtype 1, 2
• Total mastectomy is indicated ONLY when negative margins cannot be obtained with breast-conserving surgery, not based on tumor grade 1, 2

What NOT to Do Surgically

• Do NOT perform axillary lymph node dissection or sentinel node biopsy because phyllodes tumors rarely metastasize to lymph nodes (<1% have positive nodes) 1, 2
• This is a critical pitfall—axillary staging adds unnecessary morbidity without any survival benefit 1, 2

Adjuvant Radiotherapy Decision-Making

Radiotherapy is NOT routinely recommended for all phyllodes tumors 1, 2

Consider radiotherapy ONLY in these specific scenarios:

• Borderline or malignant tumors >5 cm in size 1, 4
• Infiltrative tumor margins 1, 4
• Cases where clear margins could not be achieved despite re-excision attempts 1, 4
• Local recurrence, especially if additional recurrence would create significant morbidity (e.g., chest wall recurrence after salvage mastectomy) 3, 4
• Follow soft tissue sarcoma principles when considering radiation 3, 4

Systemic Therapy: What Does NOT Work

Neither chemotherapy nor endocrine therapy reduces recurrence or death in phyllodes tumors 1, 2

Critical pitfalls to avoid:

• Do NOT prescribe tamoxifen or aromatase inhibitors, even though 58% contain ER and 75% contain PR—hormone therapy has no proven efficacy 1, 2
• Do NOT use adjuvant cytotoxic chemotherapy—no evidence shows it reduces recurrence or death 1, 2
• Do NOT use breast cancer chemotherapy regimens for metastatic disease 2

Management of Local Recurrence

When a patient presents with a locally recurrent breast mass after previous phyllodes excision:

Diagnostic workup:

• History and physical examination focusing on the previous surgical site, documenting growth rate 4
• Ultrasound as the primary imaging modality 4
• Mammogram to evaluate the entire breast and contralateral side 4
• Chest imaging to screen for distant metastases, particularly in borderline and malignant subtypes 4
• Tissue sampling with histology preferred over fine needle aspiration 4

Treatment approach:

• Re-excision with wide margins (≥1 cm) without axillary staging for local recurrence without metastatic disease 3, 4
• Consider postoperative radiation therapy if additional recurrence would create significant morbidity 3, 4
• Refer borderline and malignant recurrent tumors to specialist sarcoma centers for pathology review and multidisciplinary discussion 4

Management of Metastatic Disease

• Most distant recurrences occur in the lung 1
• Surgical resection or local ablative therapy of metastatic lesions should be the primary treatment given the relatively indolent nature of these tumors 2
• When surgery is not possible or after disease progression, use sarcoma-directed chemotherapy regimens (such as Doxorubicin-Ifosfamide), NOT breast cancer protocols 2
• Follow NCCN Guidelines for Soft Tissue Sarcoma 3, 1

Prognostic Factors and Risk Stratification

• Histologic subtype affects prognosis: 5-year disease-free survival is 95.7% for benign, 73.7% for borderline, and 66.1% for malignant tumors 1, 2
• However, margin status is more important than subtype for predicting local recurrence 1
• Tumor size >5 cm, mitotic rate ≥10/10 HPF, stromal overgrowth, and stromal cellularity predict disease-free survival 5
• Local recurrence occurs in approximately 15-24% of patients despite adequate surgery 5, 6
• Approximately 20-22% of patients with malignant phyllodes develop distant metastases 5, 6

Reconstruction Timing

• Avoid immediate reconstruction in borderline phyllodes with high-risk features 1
• Delayed reconstruction is preferred after primary oncological management is completed and local recurrence risk has diminished 1

Diagnostic Considerations

• Phyllodes tumors present as rapidly enlarging, usually painless breast masses, with mean age at presentation in the 40s 1
• They often appear identical to fibroadenomas on ultrasound and mammography 1
• In the setting of a large (>2 cm) or rapidly enlarging clinical "fibroadenoma," perform excisional biopsy to pathologically exclude phyllodes tumor 1
• Do NOT rely on core needle biopsy or FNA to exclude phyllodes tumor—these may not distinguish fibroadenoma from phyllodes in most cases 3, 1