Overview

Cancer begins when cells change and grow uncontrollably, forming a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body).

About sarcoma

Both children and adults can develop a sarcoma. It can start in any part of the body, such as the bone or soft tissue. About 60% begin in an arm or leg, 30% start in the trunk or abdomen, and 10% are in the head or neck. Sarcoma is rare in adults, accounting for about 1% of all adult cancers. However, sarcoma in general represents about 15% of all cancers in children.

This section covers sarcoma of the soft tissues. Learn more about sarcoma that starts in a bone.

About soft-tissue sarcoma

Soft-tissue sarcomas (STS) are a group of cancers that begin in the tissues that support and connect the body. STS can occur almost anywhere in the body. The sarcoma cells resemble the cells that hold the body together, including fat cells, muscle, nerves, tendons, joints, blood vessels, or lymph vessels. When an STS is small, it can go unnoticed, since it does not usually cause problems early on. As an STS grows, it can cause problems with the body's normal activities.

Because there are several different types of STS, it is more of a family of related diseases rather than a single, specific disease. The specific types of sarcoma are often named according to the normal tissue cells they most closely resemble (see below). This is different from most other types of cancer, which are usually named by the part of the body where the cancer began.

Grade is the term a pathologist (a doctor who specializes in interpreting laboratory tests and diagnosing disease) uses to describe how aggressive the sarcoma is likely to be, meaning how likely it will grow and spread to another part of the body. A low-grade tumor is usually less likely to spread quickly, and it often stays in the place where it started. A high-grade tumor is more likely to spread to other places, called metastasis. Learn more about grade in the Staging section.

Experts have found many types and subtypes of sarcomas. Pathologists are now trying to find new ways to quickly determine a tumor's subtype, as this helps determine treatment. Looking at a tumor's abnormal genetics may help determine its characteristics and predict which treatments will be most effective. For at least two types of sarcoma, GIST and dermatofibrosarcoma protuberans (DFSP), major advances have been made in a type of treatment called targeted therapy (see Treatment).

Find out more about basic cancer terms used in this section.

Looking for More of an Overview?

If you would like additional introductory information, explore these related items on Cancer.Net:

• Cancer.Net Patient Education Video: View a short video led by an ASCO expert in this type of cancer that provides basic information and areas of research.
  
  
• Cancer.Net En Español: Read about sarcoma in Spanish.

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