Aggressive Fibromatosis (Desmoid Tumor)

Aggressive Fibromatosis (Desmoid Tumor) – Treatment Options

Introduction
Aggressive fibromatosis, also known as a desmoid tumor, is a rare, locally invasive soft tissue tumor that arises from fibroblasts. While it does not metastasize, it can infiltrate surrounding structures and cause significant morbidity. Desmoid tumors may occur sporadically or in association with familial adenomatous polyposis (FAP, Gardner’s syndrome). Clinical presentation depends on tumor location—common sites include the abdominal wall, mesentery, and extremities. Management focuses on balancing tumor control with preservation of function and quality of life, since spontaneous stabilization or regression is possible in some cases.

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1. Active Surveillance (“Watchful Waiting”)

• Many desmoid tumors show periods of stability or spontaneous regression.

• Recommended for asymptomatic patients or those with non-threatening tumor locations.

• Regular monitoring with MRI or CT scans every 3–6 months initially.

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2. Surgical Resection

• Historically the primary treatment, but now reserved for selected cases.

• Complete surgical excision with negative margins may be curative, but recurrence rates are high (20–50%).

• Avoided if surgery risks significant morbidity or loss of function.

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3. Radiotherapy

• Option for unresectable tumors or postoperative residual disease.

• May provide long-term local control, especially for extra-abdominal tumors.

• Side effects include fibrosis, secondary malignancy (rare), and impaired growth in younger patients.

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4. Systemic Therapy

• Used in progressive, symptomatic, or unresectable disease.

• Non-cytotoxic agents:

  • NSAIDs (e.g., sulindac) and anti-estrogen therapy (tamoxifen, toremifene) have shown benefit in some patients.

• Cytotoxic chemotherapy:

  • Low-dose methotrexate with vinblastine or vinorelbine – effective in progressive disease with tolerable toxicity.

  • Anthracycline-based regimens (doxorubicin, liposomal doxorubicin) – reserved for aggressive or refractory cases.

• Targeted therapies:

  • Tyrosine kinase inhibitors (TKIs): Imatinib, sorafenib, pazopanib – demonstrated activity in clinical trials.

  • Gamma-secretase inhibitors (e.g., nirogacestat): Show promise in clinical studies for refractory desmoid tumors.

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5. Supportive and Rehabilitative Care

• Pain management with analgesics or NSAIDs.

• Physical therapy to preserve mobility and function in extremity involvement.

• Psychological support, as chronic disease course can cause anxiety and distress.