Fibrosarcoma

A fibrosarcoma is a malignant (cancerous) tumor that originates in the connective fibrous tissue found at the ends of bones of the arm or legs, and then spreads to other surrounding soft tissues. It is a type of soft tissue tumor, a type of tissue which includes fat, muscles, tendons (bands of fiber that connect bones to muscle), nerves, joint tissue, blood vessels, and other fibrous tissue. Fibrosarcoma most commonly affects either a lower leg or arm.

Infantile fibrosarcoma

Congenital fibrosarcoma, also called infantile fibrosarcoma, is a type of tumor among the most common soft tissue sarcoma found in children under 1 year of age. It presents as a rapidly growing mass at birth or shortly after. This form of fibrosarcoma is usually slow-growing and tends to be more benign than fibrosarcoma in older children, which behaves more like the type found in adults.

Adult form fibrosarcoma

The adult form of this disease can occur in older children and in adolescents, roughly between the ages of 10 and 15. It is more aggressive than the infantile form and generally involves more complex treatment.

Each child may experience fibrosarcoma symptoms differently, depending on the size, location, and spread of the tumor.

Fibrosarcoma symptoms may include:

• Painless or tender mass in an extremity or trunk
• Pain or soreness caused by suppressed nerves and muscles
• Limping or other difficulty using legs, feet, arms, and hands

Fibrosarcoma symptoms may resemble other conditions or medical problems. Always consult a physician for a diagnosis.

The exact cause of fibrosarcoma and other soft tissue tumors is not entirely understood, however, studies have indicated that genetic alterations may play a role. Researchers have studied a small number of families that contain several members from one generation who have developed soft tissue sarcomas. In addition, limited studies have shown a possible link between soft tissue sarcomas and the development of other types of cancer. A chromosomal rearrangement has been found in some fibrosarcomas.

In addition to a complete medical history and physical examination of your child, diagnostic procedures for fibrosarcoma may include:

Multiple imaging studies of the tumor and sites of possible metastasis, such as:

• X-ray
• Magnetic resonance imaging (MRI)
• Computerized tomography scan (also called a CT or CAT scan)
• Bone scans
• Complete blood count (CBC)
• Blood tests (including blood chemistries)
• Biopsy of the tumor

Once fibrosarcoma has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate, and gives some indication of prognosis.

A fibrosarcoma may be localized, meaning it has not spread beyond the bone where it arose. Its growth may also reach beyond nearby tissues, or metastatic, meaning it has spread to lungs, bones other than the bone that the tumor originated in or to other organs or structures of the body. Tumors found during infancy are usually not metastatic.

Fibrosarcoma treatments have improved dramatically in recent years, particularly for patients with localized disease. Most of the time, there are two components in treating children with newly diagnosed fibrosarcoma: local control, which involves treating the tumor itself, usually through surgery, radiation, or a combination; and systemic therapy, which treats any tumor cells throughout the body, usually through chemotherapy. Fibrosarcoma can usually only be cured by using local control together with systemic therapy.

Chemotherapy

Treatment for fibrosarcoma almost always begins with chemotherapy, which aims to destroy or shrink cancer cells and prevent them from spreading. Most children with fibrosarcoma respond very well to chemotherapy.

Chemotherapy is usually given over a period of a few days every two weeks for about 12 weeks before it is time for local control of the main tumor. After surgery and/or radiation for local control, chemotherapy is continued for another four to six months in order to eliminate all the cancerous cells in the body. We give chemotherapy cycles every two weeks in fibrosarcoma because studies show that this schedule (called “interval compression”) improves outcomes for children with localized fibrosarcoma.f

The typical chemotherapy regimen for a child with newly diagnosed fibrosarcoma involves medicines given intravenously (or “IV”) as a direct injection into the blood stream. This chemotherapy used to be given during overnight stays in the hospital. Now through our home hydration program, most children are able to receive this regimen as an outpatient.

While chemotherapy can be quite effective in treating certain cancers, the drugs cannot differentiate normal healthy cells from cancer cells. As a result, there can be adverse side effects during treatment. Being able to anticipate these side effects can help the care team, child, and family prepare (and, in some cases, prevent) these complications from occurring, if at all possible.

Surgery at Dana-Farber/Boston Children’s Hospital Cancer and Blood Disorders Center is personalized to help your child achieve the best functional and cosmetic outcome and to allow them to remain active and healthy. Depending on the type of surgery your child receives, your child may have to avoid certain physical activities following treatment.

Prognosis for fibrosarcoma greatly depends on:

• The extent of the disease
• The size and location of the tumor
• Presence or absence of metastasis
• The tumor's response to therapy
• The age and overall health of the child
• Your child's tolerance of specific medications, procedures, or therapies
• New developments in treatment

Children with fibrosarcoma are treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center through our Bone and Soft Tissue Program. Our integrated pediatric oncology program offers the combined expertise of a leading cancer center and a world-renown children’s hospital.