Desmoid Tumors

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Desmoid tumors are rare, aggressive soft-tissue tumors characterized by locally invasive growth, significant morbidity, and a high rate of recurrence. They are often debilitating and disfiguring and can invade surrounding healthy tissues, including joints, muscle, and viscera.

Desmoid tumors do not metastasize (spread from one body part to another), however, they are known for having unpredictable behavior and treatment approaches may vary across patients. These tumors can cause severe pain and morbidity resulting from disfigurement, vascular constriction, and loss of physical function. When aggressive and near or involving vital structures, desmoid tumors can be life-threatening.

Where do desmoid tumors grow?

While desmoid tumors can arise in any part of the body, the most common sites are the upper extremities (arm, forearm, and hand), lower extremities (hip, thigh, leg, and foot), abdominal wall, thoracic areas, and the head and neck.

  • Head & Neck (8%)
  • Upper Extremities (14%)
  • Lower Extremities (16%)
  • Thoracic/Chest Wall (15%)
  • Intra-abdominal (20%)
    • Occurs more frequently in patients with Familial Adenomatous Polyposis (FAP)
  • Abdominal Wall (16%)
  • Other locations (11%)

Source: Constantinidou, Anastasia & Scurr, Michelle & Judson, Ian & Litchman, Charisse. (2012). Clinical Presentation of Desmoid Tumors. 10.1007/978-94-007-1685-8_2.

What are the symptoms?

The severity of a desmoid tumor generally depends on the size and location of the tumor and the aggressiveness of its growth pattern. Typically, if the tumor is in the extremities or on the chest wall, most patients will notice a lump as the initial clinical presentation. Desmoid tumors can cause severe pain and morbidity resulting from disfigurement, vascular constriction, and loss of physical function. When aggressive and near or involving vital structures, desmoid tumors can be life-threatening.

Who gets desmoid tumors?

While desmoid tumors can occur in people of almost any age, they are most commonly diagnosed in adults between 30-40 years of age. Women are also two to three times more likely to be diagnosed with a desmoid tumor than men. It is estimated that there are 1,000 to 1,500 new cases diagnosed each year in the United States with a population-proportionate incidence in other countries.

What are the treatment options?

There are currently no medicines approved for the treatment of desmoid tumors. Historically, desmoid tumors were treated with surgical resection, but this approach has become less commonly recommended in recent treatment guidelines due to the documented high rates of tumor recurrence after surgery. Doctors also sometimes use systemic therapies off-label, including chemotherapies, tyrosine kinase inhibitors, and hormonal agents to try to treat desmoid tumors.

How are desmoid tumors diagnosed?

The definitive diagnosis of desmoid tumors is typically made with a core-needle biopsy, a procedure that removes tissue for pathology testing. Immunohistochemistry and genetic testing are recommended to make the diagnosis. Often it is helpful for an expert soft-tissue pathologist to confirm the desmoid tumor diagnosis to aid in an accurate and timely diagnosis.

What are the causes?

While exact causes for the development of desmoid tumors are unknown, hormone-dependent signaling, mechanical stresses, trauma, and healing processes have been proposed as possible factors involved in tumor development and growth. Desmoid tumors may be caused by genetic mutations in the DNA where fibroblasts (a cell that is critical to keeping the entire structure of our body intact) behave abnormally and turn into desmoid tumors. Other desmoid tumors are caused by mutations in a gene that causes Familial Adenomatous Polyposis (FAP). People with FAP are at high risk of developing abdominal desmoid tumors.

Our investigational therapy

Nirogacestat is an oral, small molecule gamma secretase inhibitor. SpringWorks is conducting the Phase 3 “DeFi” (Desmoid Fibromatosis) trial, a double-blind, randomized, placebo-controlled, global clinical trial in adults with progressing desmoid tumors. Additionally, in collaboration with Children’s Oncology Group (COG), a Phase 2 clinical trial is evaluating nirogacestat in children and adolescents with progressive, surgically unresectable desmoid tumors.

The FDA granted Orphan Drug Designation for nirogacestat for the treatment of desmoid tumors and Fast Track and Breakthrough Therapy Designations for nirogacestat for the treatment of adult patients with progressive, unresectable, recurrent, or refractory desmoid tumors or deep fibromatosis.

Our Phase 3 DeFi trial is evaluating nirogacestat, an oral, small molecule gamma secretase inhibitor (GSI) in adult patients with progressing desmoid tumors.
Our Phase 2 trial in collaboration with Children's Oncology Group (COG) is evaluating nirogacestat in children and adolescents with progressive, surgically unresectable desmoid tumors.

Looking for support?

The mission of The Desmoid Tumor Research Foundation is to aggressively fund research to accelerate the development of improved therapies, and ultimately find a cure for desmoid tumors. The foundation collaborates with dedicated researchers and clinicians worldwide to improve the lives of patients through education, awareness, and support.