Soft Tissue Sarcoma in Children

1. What is soft tissue sarcoma in children?

Soft-tissue sarcomas are rare cancers in children and adolescents, representing only 7.4 % of cancer cases in children <20 years of age. In this type of cancer, the  malignant (cancer) cells develop from the soft tissues of the body. Soft tissue sarcoma may be found anywhere in the body. In children, the tumors occur most often in the arms, legs, chest, or abdomen. They are categorized into rhabdomyosarcomas (RMS) and non-rhabdomyosarcoma soft-tissue sarcomas (NRSTS).

2. What are the different types of soft tissue in the body?

Soft tissues of the body connect, support, and surround other body parts and organs

They  include the following:

• Fat

• A mix of bone and cartilage.

• Fibrous tissue.

• Muscles.

• Nerves.

• Tendons (bands of tissue that connect muscles to bones).

• Synovial tissues (tissues around joints).

• Blood vessels.

• Lymph vessels.

3. What are the different types of soft tissue sarcoma?

Following are the types of soft tissue sarcomas:

• Fat tissue tumors

• Liposarcoma.

• Fibrosarcoma.    

• Rhabdomyosarcoma.

• Leiomyosarcoma.

• Nerve sheath tumors

• Synovial sarcoma.

• Blood vessel tumors

4. What are the signs and symptoms of soft tissue sarcoma in children?

The most common sign of childhood soft tissue sarcoma is a painless lump or swelling in the soft tissues of the body.There may be no other signs or symptoms at first. As the sarcoma gets bigger and presses on the surrounding organs, nerves, muscles, or blood vessels, it may cause signs or symptoms, such as pain or weakness.

There are many simple health problems that can  cause the same signs and symptoms. Check with your child’s doctor if you are worried it is a sarcoma.

5. What are some useful  tests that can be done when doctors suspect childhood soft tissue sarcoma?

The following tests and procedures may be performed:

•  X-rays

• Ultrasound exams

• CT scans (CAT scan)

• MRI (magnetic resonance imaging)

If tests show there is possibility of  a soft tissue sarcoma, a biopsy is done.

Biopsy is a small surgical procedure in which a part of the lump is removed as a sample. A pathologist views this under a microscope to look for cancer cells and to find out the type and grade of the tumor.

6. What factors influence the chances of recovery from a soft tissue sarcoma?

Certain factors affect the prognosis (chance of recovery) of a soft tissue sarcoma. They include: 

• The part of the body where the tumor first formed.

• The size and grade of the tumor.

• The type of soft tissue sarcoma.

• How deep the tumor is under the skin.

• Whether the tumor has spread to other places in the body and where it has spread.

• The amount of tumor remaining after surgery.

• Whether radiation therapy was used to treat the tumor before.

• Whether the cancer has just been diagnosed or has recurred (come back).

7. What is meant by stages of childhood soft tissue sarcoma?

After childhood soft tissue sarcoma has been confirmed, tests are done to find out if the cancer cells have spread to other parts of the body. These are called staging investigation. The following investigations are used to find out if cancer has spread:

• Sentinel lymph node biopsy
• PET-CT scan

8. What are the treatment options for childhood soft tissue sarcoma?

To plan treatment, it is important to know the type of soft tissue sarcoma, whether the tumor can be removed by surgery, and whether cancer has spread to other parts of the body.

There are different types of treatment for patients with childhood soft tissue sarcoma.  

• Surgery
• Radiation therapy
• Chemotherapy
• Observation
• Targeted therapy
• Immunotherapy

Surgery

Surgery means  to completely remove the soft tissue sarcoma, and is   is done whenever possible. If the tumor is very large, radiation therapy or chemotherapy may be given first, to make the tumor smaller and decrease the amount of tissue that needs to be removed during surgery. This is called neo adjuvant (preoperative) therapy.

The following types of surgery may be used:

•      Wide local excision: Removal of the tumor along with some normal tissue around it.

•      Amputation: Surgery to remove all or part of the arm or leg with cancer.

•      Lymphadenectomy: Removal of the lymph nodes with cancer.

•      A second surgery may be needed to remove any remaining cancer cells.

After the doctor removes all the cancer that can be seen at the time of the surgery, some patients may be given chemotherapy or radiation therapy after surgery to kill any cancer cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant therapy.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays to kill cancer cells or keep them from growing.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein,  the drugs enter the bloodstream and can reach cancer cells throughout the body; it is called systemic chemotherapy.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do.

Immunotherapy

It is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer.

9. What are the outcomes of soft tissue sarcoma in children?

Survival depends on the stage of the disease, positive regional nodes,  whether the tumour is of a larger size, and its invasiveness. Overall survival for RMS is around 70 % at five years, but it varies. Survival of non-rhabdomyosarcoma soft-tissue sarcomas (NRSTS) ranges from 90% for low-grade tumors to 15% for patients presenting with metastatic disease.