Sarcoma
Sarcoma, also known as “soft tissue cancer,” is the general term for a broad group of cancers that can form in various locations in the body, including the bones and the soft tissue (also called connective tissue) that connects, supports and surrounds other body structures. This includes muscle, fat, blood vessels, nerves, tendons and the lining of the joints. Most sarcomas occur in the arms, legs or trunk of the body but can occur anywhere from head to toe.
Sarcomas are rare
Sarcomas are uncommon. They make up only about 1% of all adult cancers and about 15% of cancers in children.
They are usually found when a patient has a lump or bump that does not go away and that gets larger over time. Sometimes sarcomas are identified during an X-ray or other imaging scan for another medical issue.
Early detection leads to better outcomes
The prognosis for sarcoma depends on the type and the stage at which it is diagnosed. When sarcoma is identified and treated early, the prognosis is generally positive.
The five-year survival rate for patients with small and localized soft tissue sarcomas with the tumor limited to the part of the body where it started is 81%. The majority of all soft tissue sarcomas are discovered at this stage.
What are the symptoms of sarcoma?
The first soft tissue sarcoma symptom most people notice is a lump (often on the arm or leg, sometimes on the neck or chest) that has grown over time and is not going away. The lump may or may not hurt.
When soft tissue sarcomas grow in the back of the abdomen, the symptoms often come from other issues the tumor is causing. These may include:
- Abdominal pain.
- Blockage of the bowels.
- Weight loss.
Eventually, the tumor may grow large enough that it is possible to feel a lump on the abdomen. Again, the lump may or may not hurt.
Causes of sarcoma
The specific causes for most sarcomas are unclear. In general, cancer occurs when the DNA within cells changes or mutates, causing the cells to grow out of control and form tumors that can damage tissue, bone, organs and other structures within the body.
Unlike many other types of cancer, sarcomas have very few lifestyle-related risk factors (behaviors that increase a person’s risk of developing a certain type of cancer), such as smoking, sun exposure, diet, etc.
Frequently asked questions (FAQs) about sarcoma
How fast does sarcoma grow?
According to the American Cancer Society, most stage II and III sarcomas are high-grade tumors that tend to grow and spread quickly. Some stage III tumors have already spread to nearby lymph nodes. Even when these sarcomas have not yet spread to lymph nodes, the risk of spread (to lymph nodes or distant sites) is very high.
What are early symptoms of sarcoma?
The first soft tissue sarcoma symptom most people notice is a lump (often on the arm or leg, sometimes on the neck or chest) that has grown over time and is not going away. The lump may or may not hurt.
I've heard of Ewing sarcoma and Kaposi sarcoma. How are they different?
Ewing sarcoma, found mostly in children and teenagers, is typically located in the leg bones and pelvis, but can occur in any bone. It may also form in the soft tissues of the chest, abdomen, arms, legs or other locations.
Kaposi sarcoma (KS) is a type of cancer that forms in the lining of blood and lymph vessels and typically appears as painless purplish spots on the legs, feet or face.
According to the American Cancer Society, Kaposi sarcoma is caused by infection with a virus called the Kaposi sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8). KSHV is in the same family as Epstein-Barr virus (EBV), the virus that causes infectious mononucleosis (mono) and is linked to several types of cancer.
Diagnosing sarcoma
To diagnose sarcoma, a doctor will start by asking you about your medical history. Then, they will perform a physical exam to check for symptoms such as lumps, pain or swelling.
If the doctor thinks you might have sarcoma, they will order certain diagnostic tests. These may include all or some of the following:
Imaging tests
Imaging tests can show where the tumors are located and whether they have spread from the original site to other parts of the body. These are then reviewed by a radiologist, a doctor who specializes in interpreting imaging tests.
Some of the imaging tests used to diagnose sarcoma:
- Computed tomography (CT) scans.
- Magnetic resonance imaging (MRI) scans.
- Positron emission tomography (PET) scans or PET-CT scans.
- Ultrasounds.
- X-rays.
When bone sarcoma is a possibility, the doctor may also order a bone scan.
Biopsies
Imaging tests may strongly suggest sarcoma, but a biopsy is the only definitive way to diagnose the cancer. However, because of imaging studies, a doctor may not require a biopsy before proceeding to treatment. During a biopsy, a doctor removes a small sample of the tumor, then a pathologist examines it under a microscope to confirm the presence and type of cancer cells. There are a few different types of biopsies doctors use to look for sarcoma.
For both soft tissue sarcomas and bone sarcomas, doctors may perform a core needle biopsy, during which the doctor uses a hollow needle to remove a small cylinder of tissue from the tumor. Core needle biopsies are usually done with local anesthesia, where a numbing agent is injected into the skin and other tissues over the biopsy site, although some cases may require general anesthesia (the patient is asleep).
Treatments for sarcoma
Sarcoma cancer treatment is customized to each patient and depends on the size of the tumors, the stage at which the patient is diagnosed and the patient’s general health.
Some of the primary treatments for sarcoma include radiation therapy, surgery, chemotherapy and targeted drug therapy. Many patients receive at least one or more of these treatments in combination.
Some patients may also be eligible to participate in clinical trials, which are controlled research studies of new or experimental treatments or procedures. UCHealth lists clinical trials on this page.
Radiation therapies
Radiation therapy uses high-energy beams (such as x-rays) to destroy cancer cells. It is used most often for sarcomas of the arms and legs but may also be used for other sarcomas.
Radiation may be given before sarcoma surgery (neoadjuvant radiation) to shrink tumors or after surgery (adjuvant radiation) to kill any remaining cancer cells. It is often given in combination with chemotherapy, which is known as chemoradiotherapy or chemoradiation.
External-beam radiation therapy is the primary type of radiation therapy used for treating sarcoma. This type of radiation comes from a machine that moves around the body and focuses the energy beam at the affected area. There are a few different ways this type of radiation can be administered:
Intensity modulated radiation therapy (IMRT) uses x-rays and is usually given five days a week over a five-to-six-week period. This is the most common external-beam radiation therapy for sarcoma.
Stereotactic body radiation (SBRT), sometimes called stereotactic radiosurgery (SRS) or cyberknife, also uses x-rays but the treatments involve higher doses of radiation for a shorter period of time than IMRT.
Also called internal radiation therapy, brachytherapy involves temporarily placing small pellets (also called seeds) of radioactive material in or near the tumor to kill cancer cells. For soft tissue sarcomas, these pellets are often inserted into catheters that have been placed during surgery.
Bone-seeking radioactive drugs (also called radiopharmaceuticals) are sometimes used to slow tumor growth and treat symptoms and pain in patients with bone sarcomas. These drugs are injected into a vein and collect in the bones, where the radiation they give off destroys the cancer cells.
Surgeries
Surgery is the main treatment option for sarcoma. When sarcoma is inside the abdomen, the tumor may be removed. If the sarcoma is invading or surrounding other organs, such as the kidneys, intestines or large blood vessels, these may also need to be removed and/or surgically reconstructed.
In the past, sarcomas in the arms and legs were often treated by amputating all or part of the limb. Today, most sarcomas of the limbs can be removed without amputation. The goal of limb-sparing or limb-salvage surgery is to remove the entire tumor, along with at least 1 to 2 cm of the normal tissue around it to ensure no cancer cells are left behind. This area of healthy tissue around the tumor is called the margin, and the procedure is called a wide excision.
Sometimes, an amputation may be the only way to remove all of the cancer, or it may be the best option if removing the tumor would result in loss of limb function or chronic pain due to bone or tissue damage. Reconstructive surgery and the use of prosthetic (artificial) limbs may be options for patients who undergo amputation to help them regain function afterward.
Chemotherapy
Chemotherapy is a drug treatment to kill cancer cells. Some types of sarcomas respond better to chemotherapy than others.
Like radiation therapy, chemotherapy may be used before surgery to try to shrink the tumors or after surgery to kill any remaining cancer cells.
Chemotherapy for sarcoma may be administered throughout the body (systemic chemotherapy), or it may be targeted at an affected arm or leg.
Drugs for systemic chemotherapy can be injected into a vein (IV) or taken by mouth in pill form. These drugs enter the bloodstream and circulate throughout the body. The most common chemotherapy drugs for sarcoma are ifosfamide (Ifex) and doxorubicin (Adriamycin). Patients who receive ifosfamide are also given the drug mesna to protect the bladder from the toxic effects of ifosfamide.
Five-year sarcoma (soft tissue) cancer survival rates
Data source: Surveillance, Epidemiology, and End Results (SEER) 17 registries, National Cancer Institute, 2022. AJCC All Stages, 5 Year Relative Survival. SEER survival rate is for persons diagnosed between 2013–2019.
References
National Cancer Institute (NCI). Soft Tissue Sarcoma (https://www.cancer.gov/types/soft-tissue-sarcoma)
National Center for Biotechnology Information (NCBI): National Library of Medicine. Sarcoma (https://www.ncbi.nlm.nih.gov/books/NBK519533/)
MedlinePlus: National Library of Medicine. Soft Tissue Sarcoma (https://medlineplus.gov/softtissuesarcoma.html)