What is the recommended treatment for a patient with a suspected Phylodes tumor?

Recommended Treatment for Phyllodes Tumor

All phyllodes tumors—benign, borderline, and malignant—require surgical excision with tumor-free margins of at least 1 cm, using breast-conserving surgery (lumpectomy or partial mastectomy) as the preferred approach, reserving mastectomy only when negative margins cannot be achieved. 1, 2

Initial Diagnostic Approach

• Suspect phyllodes tumor in any woman presenting with a rapidly enlarging, usually painless breast mass, particularly if the patient is in her 40s or has a large mass (>2 cm). 1
• Imaging (ultrasound/mammography) often cannot distinguish phyllodes from fibroadenoma, so perform excisional biopsy for any large (>2 cm) or rapidly growing clinical "fibroadenoma" to pathologically exclude phyllodes tumor. 1
• Core needle biopsy may miss the characteristic leaf-like architecture and lead to misdiagnosis, particularly in spindle cell-predominant variants. 1

Surgical Management Algorithm

Primary Surgery

• Perform wide local excision (lumpectomy/partial mastectomy) with ≥1 cm tumor-free margins as first-line treatment for all subtypes. 1, 2
• Total mastectomy is indicated ONLY if negative margins cannot be obtained with breast-conserving surgery. 1, 2
• If initial margins are close (<5 mm) or positive, attempt re-excision to achieve clear margins if feasible, as margin status is the single most important factor for preventing local recurrence. 3, 1

Axillary Management

• Do NOT perform axillary lymph node dissection or sentinel node biopsy—phyllodes tumors rarely metastasize to lymph nodes (<1% have positive nodes). 1, 2, 4
• This is a critical pitfall to avoid, as axillary staging adds unnecessary morbidity without benefit. 1

Adjuvant Radiotherapy Decision Tree

Radiotherapy is NOT routinely recommended for all phyllodes tumors but improves local control (not survival) in specific high-risk scenarios: 3, 1

Consider Radiotherapy For:

• Malignant phyllodes tumors >5 cm in size 3, 1, 4
• Borderline phyllodes with high-risk features: large tumors, infiltrative margins, especially if clear margins could not be achieved surgically 3, 1
• Close (<5 mm) or positive margins despite re-excision attempts 3
• Multifocal or recurrent disease, irrespective of surgery type (breast-conserving surgery versus mastectomy) 3

Do NOT Use Radiotherapy For:

• Benign phyllodes tumors with negative margins 1
• Routine use in all borderline or malignant cases without high-risk features 1

Adjuvant Systemic Therapy

Neither chemotherapy nor endocrine therapy has any proven role in phyllodes tumor treatment and should NOT be used. 1, 2

• Despite 58% containing ER and 75% containing PR, endocrine therapy (tamoxifen, aromatase inhibitors) does not reduce recurrence or death. 1, 2
• Adjuvant cytotoxic chemotherapy has no evidence for reducing recurrence or death. 1, 2
• Do NOT use breast cancer chemotherapy regimens for phyllodes tumors—these are managed with sarcoma principles, not epithelial breast cancer protocols. 2

Reconstruction Timing

• Avoid immediate reconstruction in borderline or malignant phyllodes tumors, particularly with high-risk features (large, high-grade tumors). 3, 1
• Delayed reconstruction is strongly preferred after completion of primary oncological management (including radiotherapy if indicated) and when local recurrence risk has diminished, typically within the first 2 years after diagnosis. 3, 4

Management of Recurrence

Local Recurrence

• Re-excision with wide tumor-free surgical margins is the treatment of choice. 1, 2
• Consider postoperative radiotherapy if additional recurrence would create significant morbidity. 1
• Local recurrence occurs in approximately 15-24% of patients and is more common after incomplete excision. 5, 6, 7

Distant Metastases

• Most distant recurrences occur in the lung and should be treated with surgical resection or local ablative therapy as the primary approach, 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

Multidisciplinary Management

Borderline and malignant phyllodes tumors should be referred to specialist sarcoma centers for pathology review and multidisciplinary team discussion between breast cancer MDT and sarcoma MDT. 3

Prognosis by Subtype

• 5-year disease-free survival rates: 95.7% for benign, 73.7% for borderline, and 66.1% for malignant tumors 1, 2, 4
• Approximately 20% of patients with malignant phyllodes develop distant metastases. 7
• Tumor features (stromal overgrowth, mitotic rate ≥10/10 HPF, stromal cellularity, size >5 cm) predict recurrence and survival more than surgical extent. 6

Critical Pitfalls to Avoid

• Do NOT rely on core needle biopsy or FNA alone to exclude phyllodes tumor in a rapidly growing or large breast mass. 1
• Do NOT perform routine axillary staging—this adds unnecessary morbidity without benefit. 1, 2
• Do NOT use adjuvant chemotherapy or endocrine therapy—these have no proven efficacy. 1, 2
• Do NOT routinely recommend radiotherapy for all phyllodes tumors—reserve for high-risk cases only. 1
• Do NOT accept inadequate surgical margins—this is the most important factor for preventing local recurrence. 1
• Do NOT treat phyllodes tumors as epithelial breast cancer—they require sarcoma-directed management principles. 4