Alveolar Soft Part Sarcoma (ASPS)

Fact: Fewer than 80 cases are diagnosed per year in the U.S.


What is alveolar soft-part sarcoma?
Alveolar soft-part sarcoma is a rare type of cancer called a sarcoma, which is a malignant tumor affecting soft tissues like fat, muscle and nerves. It occurs mainly in children, but can also appear in adults.

This type of tumor grows slowly but spreads and returns easily. It generally starts in the limbs (legs and arms), as well as the head and neck.
The cause of alveolar soft-part sarcoma is not clear. It is not passed on from parents to children through the genes.

Alveolar soft-part sarcoma usually appears as a non-painful lump in a leg or buttock. Nodules form the lump tend to travel to the lungs, brain and liver. Alveolar soft-part sarcoma does not usually produce symptoms right away. So, it can spread and grow before its cells have become large enough to be noticed and treated.

Most patients with alveolar soft part sarcoma probably have had the cancer for some time before they come to medical attention. The reason is that the tumor grows so slowly that it at first causes few symptoms and does not form a large mass. By the time the tumor is big enough that the patient feels a lump from the primary lesion and seeks out a physician for help, the tumor has frequently spread, establishing small metastatic colonies throughout the body, frequently found in the lungs and even the brain. It grows even more slowly than clear cell sarcoma, but is definitely a malignant tumor that tends to spread inexorably if not completely removed by surgery.

ffected Populations
ASPS tends to affect younger people, especially those between 15 and 35 years of age. It is rare in children under 5 or in adults over 50. Women outnumber men, especially under age 25. There appears to be no link of this tumor to a particular ethnicity. ASPS accounts for about 0.2-1% of all soft tissue sarcomas. In turn, soft tissue sarcomas account for approximately 1% of all cancers.

What are the signs and symptoms of alveolar soft-part sarcoma?
Alveolar soft-part sarcoma can go unnoticed for a long time before it is diagnosed. When the tumor grows large enough, it starts pushing on the tissues and structures around it. Symptoms vary depending on the location of the tumor and may include the following:

  • A painless swelling or mass in the leg, buttocks, neck or chest
  • Secondary symptoms caused by the tumor pressing on nerves or muscles in the affected area
  • Decreased range of motion in the arms and legs
  • Limping
  • Muscle stiffness

Biopsy is the fastest way to come to a diagnosis of soft-tissue sarcomas. A biopsy involves taking a small sample of affected tissue and examining it under a microscope. There are more than 50 different types of sarcomas, of which ASPS is only one rare subtype. Often times, a core needle biopsy of the leg mass is enough to make the diagnosis. If a core needle biopsy is not diagnostic, then an incisional biopsy that obtains more tissue will make the diagnosis.

Typically, people will also undergo specialized imaging techniques such as computed tomography (CT) scans or magnetic resonance imaging (MRI) scans of the primary tumor site to determine if the mass is removable. A CT scan of the chest is typically performed to determine if there is disease in the lungs. Additional scans may also be considered to assess for the spread of cancer to other areas of the body. ASPS, generally does not move to lymph nodes, instead preferring to travel via the blood to get to the lungs or other parts of the body.

How is alveolar soft-part sarcoma treated?
A team of doctors from many specialties will work to determine a course of treatment for alveolar soft-part sarcoma. The most common option combines the following therapies:

  • Surgery—A surgical oncologist (a cancer surgeon) removes the tumor and any surrounding tissues (margin). Since alveolar soft-part sarcoma often comes back after treatment, the surgeon may want to take a wide margin of tissue to get all of the cancer. If the tumor is in an arm or leg, this surgery might include removal of part or all of the arm or leg.
  • Radiation (radiotherapy)—In this treatment, a radiation oncologist uses light energy such as high-energy X-rays to destroy or reduce the size of tumor cells. It is usually painless but can cause temporary side effects such as skin problems, diarrhea, fatigue and stomach problems.
  • Targeted drug therapy—Traditional chemotherapy (drugs that slow tumor cell growth or destroy it) usually is does not work well for alveolar soft-part sarcoma. In addition, the effects of chemo are severe and affect many parts of the body, making it a poor treatment choice for this cancer. Researchers have turned their focus to more targeted therapies that destroy the alveolar soft-part sarcoma cells without harming nearby healthy tissues. Such therapies include drugs such as cediranib and sunitinib. These drugs starve alveolar soft-part sarcoma tumors by cutting off blood flow to them. These drugs are being tested in clinical trials.

Want to learn more?
The following are organizations and/or websites dedicated to providing information and education surrounding Aveolar Soft Part Sarcoma. These organizations are dedicated to research, education, awareness, and/or support. They are listed in Alphabetical order without any preference or prejudice. Listing these organizations is not a recommendation or referral in any regard for seeking treatment or consultation or support for treatment.

Boston Children's Hospital
The Liddy Shriver Sarcoma Initiative
Sarcoma Foundation of America
St. Jude Children's Research Hospital

Information on this page taken directly from:
Sarcoma Foundation of America
St. Jude Children's Research Hospital