What Is a Soft Tissue Sarcoma?

Medically Reviewed by Jennifer Robinson, MD on March 18, 2024
7 min read

Soft tissue sarcomas are a group of cancers that grow in parts of your body such as your muscles, bones, deep layers of skin, or in fat. They also can form on blood vessels, nerves, or connective tissues, which support organs and other kinds of tissues.

Soft tissue sarcomas are rare. They account for less than 1% of all cases of cancer. But there are dozens of different types, and they can happen in children and adults.

About 13,000 people are diagnosed with one of these cancers every year.

Doctors aren’t sure why these types of cancers happen, but some things may raise your chances of having one:

A family history of certain diseases that you can inherit from your parents. These include neurofibromatosis and Gardner syndrome, which are disorders that make tumors grow in parts of your body.

Certain chemicals like arsenic, vinyl chloride, or dioxin.

Radiation, including during treatment for other kinds of cancer.

The most common sign of a soft tissue sarcoma is a painless lump or growth. But some may not be noticeable until they’re big enough to press on nearby muscles or nerves.

About 1 in 5 soft tissue sarcomas happen in the belly. You probably wouldn’t learn that you have one until they caused other problems, such as stomach pain, bleeding, or a blocked intestine. A doctor might find a sarcoma in your lungs or chest only after you have chest pain or trouble breathing.

About 10% of the time, a sarcoma will start on your head or neck. The most common type of soft tissue sarcoma in children, called rhabdomyosarcoma, happens mostly in those areas.

You should see your doctor if:

  • You notice a growing lump somewhere on your body.
  • You have stomach pain that’s getting worse.
  • Your stool appears black or bloody.
  • You’re vomiting blood.

Most visible lumps aren’t sarcoma. They’re usually a harmless cluster of fat cells called a lipoma. But if you have one that’s bigger than 2 inches and growing or causing pain, see your doctor.

If your doctor thinks you may have a sarcoma, you’ll probably get:

A physical examination. Your doctor will look closely at any lumps or bumps.

Imaging tests. These might include:

  • X-rays
  • An ultrasound. This uses sound waves to show an image of the inside of your body on a monitor. It’s usually used to look inside your belly.
  • An MRI scan. This uses powerful magnets and radio waves to make detailed images of the inside of your body. It’s typically used for your arms or legs.

A biopsy. Your doctor will take a sample of the growth to look at under a microscope. Most of the time, this can done with a needle, but in some cases, you might need minor surgery.

If the tests show that you have cancer, your doctor will use the results to find out the stage of the cancer. That’s a number I through IV that’s based on how big it is and whether it’s in other parts of your body.

You may want to ask:

  1. How do you know it’s cancer? Could it be something else?
  2. What kind of soft tissue sarcoma do I have?
  3. How far has it spread?
  4. What kind of treatment should I get, and why?
  5. How well does that treatment work?
  6. What kind of side effects will I have if I get that treatment?
  7. Are there other ways to treat this kind of cancer?
  8. Who will be in charge of my treatment?
  9. How often have they treated this kind of cancer?
  10. What do I need to do to prepare for my treatment?
  11. If I have another health condition, how will it be affected?
  12. What support is available to help me and my family?
  13. Where can I learn more about my type of cancer?

This will depend on where the cancer is and how far it’s spread, but surgery is usually the first step.

Your doctors will try to take out any tumors without harming the healthy tissue around them.

They might take out one or more of your lymph nodes to check if your sarcoma has reached them and spread to other places in your body.

If a tumor is in one of your arms or legs, your doctors may try to replace any tissue they have to take out. They might use tissue from another part of your body or artificial implants. In rare cases, your doctors may have to remove a limb.

For some people, surgery may be all it takes to get rid of the cancer. But if a sarcoma has spread to other parts of your body, your doctor also may recommend chemotherapy, which uses strong drugs to attack cancer cells as they grow. You might get these medicines through an IV, or you might take them as pills.

If the tumor is too hard to take out completely or you’re too ill to have an operation, doctors might skip surgery and go straight to radiation therapy. This uses high-energy particles or X-rays to kill cancer cells. Your doctor will use what’s known as external beam therapy, where a machine aims that radiation at part of your body. You may get it daily for several weeks. Some institutions do intraoperative radiation therapy, which you get during surgery after the tumor is removed but before the surgeon stitches you back up.

In other cases, a method called brachytherapy may be an option. Doctors put small radioactive pellets in the part of your body where the tumor is and then take them out a few days later. You may have to stay in the hospital while the pellets are inside.

Your doctors also might suggest radiation therapy to shrink a tumor before they try surgery to take it out. Or they might recommend it after the surgery so they can kill any remaining cancer cells.

Chemotherapy and radiation can damage normal cells along with the cancerous ones, and that can cause some side effects.

Chemotherapy and radiation can cause nausea, vomiting, and fatigue. Chemotherapy also can make your hair fall out and lead to a loss of appetite and sores in your mouth.

Radiation also can cause redness, peeling, or blistering on your skin where the beams were aimed. If radiation targets your belly or pelvis, it may cause diarrhea. If it’s aimed at your head or chest, it may hurt to swallow.

As with any type of cancer, it could come back. Doctors call that “recurrent” soft tissue sarcoma. Your treatment for a recurrence would depend on whether it comes back in the same place or if it shows up in other parts of your body. Just like with the first time, the options might include surgery, chemotherapy, radiation therapy, or brachytherapy.

You can ask your doctor if there is a clinical trial for your type of sarcoma. These test new ways of treating cancer.

It takes a team to counter cancer. Before your treatment starts, you’ll meet with doctors, nurses, and technicians who will manage your therapy. They’ll lay out the plan they recommend and tell you about any side effects you might have. After that, you’ll be asked to sign forms saying that your doctors have told you about the procedures and that you’ve agreed to them.

Your doctors will tell you if you need to stop certain foods or activities during your treatment. Be sure to tell them about any medications (even those that you can buy “over the counter,” or without a prescription) and supplements (including vitamins and “natural” products) you take regularly.

Your therapy may keep you out of work for a while. Talk with your supervisor about your condition and whether you might need to change your schedule or duties while you get treatment. It’s against the law for your employer to treat you unfairly because of your illness.

Finding out that you have soft tissue sarcoma may change some things about your life. Surgery and other types of treatment might change how you feel about yourself and your body. Some also can affect your sex life and your ability to have children.

Having cancer can take a toll on you mentally and emotionally, as well as physically. Each person is different, but a lot of people deal with feelings of fear, anger, uncertainty, and stress. These feelings can take a toll on your loved ones as well. If those feelings are hard to handle, talk with your doctors, a counselor, clergy member, or friends.

During treatment, try to eat a healthy diet and get as much rest as you can. You may feel weak, so ask your doctors about exercises that may help you keep up your energy.

Many people know what it’s like to face cancer, and there are a lot of support groups to help you deal with the issues it causes.

These groups can help you talk about feelings and concerns you may not want to share with family or friends. They may also be a way to learn more about what to expect and how your life may change.

Some groups are led by professionals who guide the discussions, while others are led by people who are going through the same things you are. There also are groups for family members or caregivers. Your doctors, nurses, or a counselor can help you find groups that might help.