What Is Sarcoma?

Sarcoma 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. There are more than 150 different types of bone and soft tissue sarcomas.

Sarcomas are rare, accounting for 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 gets larger over time. Or they may be identified during an X-ray or other imaging scan for another medical issue. 

According to the American Cancer Society, more than 13,590 new cases of soft tissue sarcoma are diagnosed in the U.S. each year, resulting in approximately 5,200 deaths.

Osteosarcoma — the main type of sarcoma that forms in the bones — is less common, with only about 1,000 new cases diagnosed in the United States each year. Around half of these are in children and teens.

Other types of sarcomas, such as Ewing sarcomas account for a smaller percentage of overall sarcoma cancer diagnoses.

Sarcoma Survival Rates and Prognosis

The prognosis for patients with sarcoma depends on the type of sarcoma 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.

Why Come to CU Cancer Center for Sarcoma Cancer

As the only National Cancer Institute Designated Comprehensive Cancer Center in Colorado and one of only four in the entire Rocky Mountain region, the University of Colorado Cancer Center has doctors dedicated to the treatment of sarcoma who provide patient-centered sarcoma cancer care and researchers dedicated to diagnostic and treatment innovations.

Two New Grants Help CU Researchers Test New Sarcoma Treatments

The CU Cancer Center is home to the Sarcoma Multidisciplinary Clinic, which offers patients an “all in one” approach to clinical care. At a multidisciplinary clinic, patients are evaluated in one visit by specialists who treat this specific cancer, including world-class medical oncologists, surgical oncologists, orthopedic oncologists, radiation oncologists, interventional radiologists, pathologists, radiologists, nurse practitioners, physician assistants, nurses, social workers, nutritionists, and others, who then collaborate on care. The team also works with plastic surgeons, urologists, thoracic surgeons, cardiologists, and fertility specialists to provide each patient with the optimal course of treatment and follow-up care. 

There are multiple sarcoma clinical trials being offered by CU Cancer Center members at any time. These trials offer patients options beyond traditional sarcoma treatment and can result in remission or increased life spans. Trials conducted by CU Cancer Center doctors have led to the development of some of the most recently approved drugs for sarcoma.

For more information on pediatric tumors including Ewing’s sarcoma, and to learn more about the care team and treatment options, visit the Pediatric Orthopedic Tumor Program and Orthopedic Oncology Program at Children’s Hospital Colorado.

Types of Sarcoma

There are more than 150 different types of sarcoma, and each one is named and classified based on the type of cell in which it forms. These are identified by looking at the cells under a microscope. Doctors use this information to understand the expected growth pattern and aggressiveness of the cancer, which can help determine the best options for treatment.

The most common types of sarcoma are soft tissue sarcomas and bone (osteo) sarcomas. The list below describes some of the most common types of soft tissue and bone sarcomas, but there are many more.

Types of Soft Tissue Sarcoma

Undifferentiated pleomorphic sarcoma (UPS) is most often found in the arms or legs, though it can also form in the soft tissues behind the abdominal organs (the retroperitoneum). The name is based on the way the cancer cells look under the microscope: “undifferentiated” because the cells don't look like the body tissues in which they develop and “pleomorphic” because the cells grow in different shapes and sizes. In the past, UPS was called malignant fibrous histiocytoma (MFH). UPS is most common in older adults.

Liposarcoma begins in fat cells. The tumors can form anywhere in the body but usually occur in the legs or abdomen. Liposarcomas are most common in older adults.

Leiomyosarcoma starts in smooth muscle tissue. The tumors most often form in the abdomen, but they may also be found in other parts of the body, such as the arms, legs, uterus, large blood vessels, and skin.

Rhabdomyosarcoma (RMS) usually forms in skeletal muscle tissue or hollow organs such as the bladder or uterus. RMS is most common in children.

Gastrointestinal stromal tumors (GIST) form in the digestive tract, usually in the stomach and small intestine. GISTs are most common in adults between the ages of 50 and 70.

Fibrosarcoma usually forms in the fibrous tissue in the arms, legs, or trunk. It is most common in adults between the ages of 20 and 60.

Angiosarcoma forms in the lining of the blood vessels and lymph vessels. It occurs most often in the skin on the head and neck, but it may also form in the skin on other parts of the body, such as the breast, or in deeper tissue, such as the liver and the heart. Angiosarcoma may also occur in areas that have received radiation therapy and may develop several years after radiation therapy was delivered.

Desmoid tumors, also called aggressive fibromatosis, most often occur in the connective tissue of the abdomen, arms, and legs. Although desmoid tumors are not technically cancers (because they do not spread to other areas of the body), they can be aggressive and grow into nearby structures and organs. Treatment for desmoid tumors is similar to treatment for sarcomas and is often performed by the same doctors.  

Types of Bone Sarcoma

Osteosarcoma (also called osteogenic sarcoma) is the most common cancer that begins in the bones. It usually forms in areas where the bone is growing quickly, such as near the ends of the leg or arm bones, especially in the bones around the knee and the upper arm bone close to the shoulder. Because it often occurs in areas of bone growth, osteosarcoma is most common in children, teens, and young adults.

→ Disney+ Movie Raising Awareness of Osteosarcoma

Ewing sarcomas (also called Ewing tumors) most often form in the leg bones and pelvis, but they can occur in any bone. Less often, they may form in the soft tissues of the chest, abdomen, arms, legs, or other locations. Ewing sarcoma is most common in children and teenagers.

Chondrosarcoma usually begins in the bones, but it can sometimes occur in the soft tissue near bones. The defining characteristic of a chondrosarcoma is that its cells produce cartilage. Tumors most often form in the pelvis, hip, shoulder, and base of the skull. Chondrosarcoma is most common in middle-aged to older adults.

Sarcoma Causes and Risk Factors

The specific causes for most sarcomas are unclear. In general, cancer occurs when changes or mutations happen in the DNA within cells, 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. However, there are a few risk factors that make someone more likely to develop sarcoma.

Soft Tissue Sarcoma Risk Factors

Age: Although many types of soft tissue sarcoma typically occur in adults, some types, such as rhabdomyosarcoma are more common in children.

Inherited syndromes: Some inherited gene syndromes (also called family cancer syndromes) can increase a person’s risk of developing soft tissue sarcoma. These include hereditary retinoblastoma, Li-Fraumeni syndrome, neurofibromatosis (also called von Recklinghausen disease), tuberous sclerosis, Werner syndrome, Gardner syndrome (a type of familial adenomatous polyposis), and Gorlin syndrome (also called nevoid basal cell carcinoma syndrome).

Radiation exposure: Previous radiation treatment for other cancers (such as breast cancer or lymphoma) can raise the risk of soft tissue sarcomas.

Exposure to certain chemicals: Workers in industries that use large amounts of certain types of chemicals — such as vinyl chloride, herbicides, arsenic, and dioxin — may have a higher risk of soft tissue sarcoma.

Damaged lymph system: When lymph nodes have been removed surgically or damaged by radiation therapy, lymph fluid can build up and cause swelling. This is called lymphedema. Lymphangiosarcoma (a malignant tumor that develops in lymph vessels) is a rare complication of chronic lymphedema.

Bone Sarcoma Risk Factors

Age: The risk of osteosarcoma is highest for people between the ages of 10 and 30 and is at its peak during the teenage growth spurt. The risk decreases in middle age but increases again in older adults. Ewing sarcoma is most likely to occur in children and teenagers. The most prevalent type of chondrosarcoma typically affects middle-aged to older adults.

Height: Children with osteosarcoma are often tall for their age. 

Gender: Osteosarcoma is more common in males than females. However, females tend to develop it slightly earlier, possibly because they often go through their growth spurts earlier.

Race and ethnicity: In the United States, osteosarcoma is slightly more common in Black, Hispanic, and Latinx people than in Caucasians. Ewing sarcoma is more common in people of European ancestry.

Radiation exposure: Previous radiation treatment for other cancers can raise the risk of bone sarcomas in the areas that were exposed to radiation.

Certain bone diseases: People with certain bone diseases have a higher risk of developing osteosarcoma. These include Paget disease, hereditary multiple osteochondromas, and fibrous dysplasia. People with Ollier disease and Maffucci syndrome (conditions marked by an increased number of benign cartilage lesions) have a higher risk of developing chondrosarcoma.

Inherited syndromes: Some inherited gene syndromes (also called family cancer syndromes) can increase a person’s risk of developing osteosarcoma. These include hereditary retinoblastoma, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, Bloom syndrome, Werner syndrome, and Diamond-Blackfan anemia.

Symptoms of Sarcoma

The earlier sarcoma is diagnosed and treated, the better the prognosis, so it’s important to understand the most common sarcoma cancer symptoms.

Soft Tissue Sarcoma Symptoms

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.  

Bone Sarcoma Symptoms

Bone pain at the site of the tumor (often around the knee or in the upper arm) is the most common symptom of bone sarcomas. The pain often increases with activity and/or may be worse at night. Depending on the location of the tumor, it may be possible to feel a lump or mass.

Other symptoms of bone sarcomas can include:  

  • Swelling in the immediate area of the tumor.
  • Limb pain and swelling.
  • Bone fractures (breaks) that happen unexpectedly, such as with a minor injury or no injury at all.

Additional symptoms of Ewing sarcomas may include unexplained fatigue, fever, and weight loss.

Sarcoma symptoms can also be caused by other medical conditions, so anyone experiencing these symptoms should check with a doctor to learn the cause. 

Diagnosing Sarcoma

To diagnose sarcoma, a doctor will start by asking about the patient’s medical history. Then, they will perform a physical exam to check for symptoms such as lumps, pain, or swelling.

If the doctor thinks a patient may have sarcoma, they will order diagnostic tests. These may include all or some of the following.

Imaging Tests for Sarcoma

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 include x-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, ultrasounds, and positron emission tomography (PET) scans or PET-CT scans. When bone sarcoma is a possibility, the doctor may also order a bone scan.

Biopsies for Sarcoma 

Although imaging tests may strongly suggest sarcoma, 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 this type of biopsy, a 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 (where the patient is asleep).

Another option for diagnosing bone sarcoma is a surgical biopsy (also called an open biopsy). During this type of biopsy, a surgeon makes an incision in the skin and then removes all or some of the tumor. These biopsies are usually done in a procedure room using a numbing agent or in an operating room while the patient is under general anesthesia or has a nerve block placed to numb that area of the body.

Staging Sarcoma

After confirming the presence and type of sarcoma, the doctor will try to determine the stage of the disease. This is based on several factors, including the size of the tumor, the tumor grade (how abnormal the sarcoma cells look under a microscope), and whether it has spread beyond the original site. The stage significantly impacts both the prognosis and treatment options.

Many of the same tests used to diagnose sarcoma are also used to assign a stage, as well as additional procedures, such as blood tests. For example, high levels of certain chemicals in the blood can suggest that osteosarcoma may be more advanced.

TNM Staging System for Sarcoma

Both soft tissue and bone sarcomas may be staged using the TNM system, which measures the size and extent of the tumor (T-tumor); whether the cancer has spread to nearby lymph nodes (N-node); and whether the cancer has spread or metastasized (M-metastasis) to distant parts of the body, such as the lungs or other bones.

For sarcoma, the TNM staging system also includes the grade (G-grade) of the tumor, which ranges from 1 to 3 and is based on how the cells look under the microscope. Low-grade tumor cells (grade 1) look more like healthy cells and are less likely to grow and spread quickly, while high-grade tumor cells (grade 3) look more abnormal.

Soft Tissue Sarcoma Stages

Stage 1: The tumor has not spread to nearby lymph nodes or distant sites. The cancer is grade 1 or the grade cannot be assessed.

Stage 2: The tumor is 5 cm or smaller and has not spread to nearby lymph nodes or distant sites. The cancer is grade 2 or grade 3.

Stage 3: The tumor is larger than 5 cm and has not spread to nearby lymph nodes or distant sites; it is grade 2 or grade 3. Or the tumor is any size and has spread to nearby lymph nodes but not distant sites; it can be any grade.

Stage 4: The tumor is any size and has spread to nearby lymph nodes and distant sites. It can be any grade.

Bone Sarcoma Stages

Stage 1: The tumor has not spread to nearby lymph nodes or distant sites. The cancer is grade 1 or the grade cannot be assessed.

Stage 2: The tumor is still in only one part of the bone and has not spread to nearby lymph nodes or distant sites. The cancer is grade 2 or grade 3.

Stage 3: The tumor is in more than one place on the same bone. It has not spread to nearby lymph nodes or distant sites. The cancer is grade 2 or grade 3.

Stage 4: The tumor can be any size and may be in more than one place in the bone. It may have spread to nearby lymph nodes. It may have spread to distant organs like the lungs, liver, brain, or other bones. The cancer can be any grade.

The stages for both soft tissue and bone sarcomas can be further broken down based on the size and spread of the cancer. 

Localized Versus Metastatic Osteosarcoma

For treatment purposes, surgeons may also use a simpler system that divides bone sarcomas like osteosarcoma into two groups: localized and metastatic.

A localized osteosarcoma is confined to the bone where it started and possibly the tissues near to the bone, such as muscle, tendon, or fat. Most osteosarcomas are diagnosed while they are still localized.

Localized osteosarcomas can be further categorized as resectable (able to be removed by surgery) and non-resectable or unresectable (unable to be removed by surgery).

A metastatic osteosarcoma has spread to other parts of the body beyond the bone where it started, such as the lungs, liver, brain, or other bones. Metastatic sarcomas are harder to treat, but some can be cured if the metastases can be removed by surgery. The cure rate improves significantly if the patient also received chemotherapy.


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. Sarcoma care teams may include numerous health care professionals, such as primary care providers, orthopedic surgeons, surgical oncologists, medical oncologists, pediatric oncologists, thoracic surgeons, and radiation oncologists, as well as physician assistants, nurse practitioners, dietitians, pain specialists, nurses, psychologists, social workers, and physiatrists (rehabilitation doctors).

Some of the primary treatments for sarcoma include surgery, radiation therapy, 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 — controlled research studies of new or experimental treatments or procedures.

Surgeries for Sarcoma

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.

For bone sarcomas, the section of bone that is removed may be replaced with a piece of bone from another part of the body or from another person (a bone graft) or with a synthetic device (an internal prosthesis). Some devices combine a graft and a prosthesis.

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.

Radiation Therapy for Sarcoma

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 for Sarcoma

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.

Brachytherapy for Sarcoma

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.

Radioactive Drugs for Sarcoma

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.

Chemotherapy for Sarcoma

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.

Other chemo drugs for sarcoma include dacarbazine (DTIC), epirubicin, temozolomide (Temodar), docetaxel (Taxotere), gemcitabine (Gemzar), vinorelbine (Navelbine), trabectedin (Yondelis), eribulin (Halaven), methotrexate, doxorubicin (Adriamycin), cyclophosphamide, etoposide, and cisplatin or carboplatin. Chemotherapy drugs may be administered alone or in combination.

Targeted Therapy for Sarcoma

Targeted therapies use drugs to inhibit the action of defective genes and slow or halt the growth and spread of sarcoma cancer cells while limiting harm to healthy cells.

Pazopanib (Votrient) is approved for patients with certain advanced soft tissue sarcomas. This drug blocks several cell enzymes that are important for cell growth and survival, helping slow tumor growth and ease side effects in patients with sarcomas that cannot be removed with surgery.

Imatinib (Gleevec) is a frontline targeted drug therapy for patients with gastrointestinal stromal tumors. Imatinib is also approved for the treatment of patients with advanced-stage dermatofibrosarcoma protuberans (DFSP). Two other drugs, sunitinib (Sutent) and regorafenib (Stivarga), are approved for GIST patients in cases where imatinib does not work.

Tazemetostat (Tazverik) works by targeting EZH2, a protein that encourages cancer cell growth. This drug may be used to treat epithelioid sarcoma (a rare type of soft-tissue sarcoma) that cannot be removed completely with surgery.

The University of Colorado (CU) Cancer Center partners with UCHealth, Children’s Hospital Colorado, and Rocky Mountain Regional VA to provide clinical care. Please make an appointment with one of our clinical partners to be seen by a CU Cancer Center doctor.


UCHealth Cancer Care - Anschutz Medical Campus
1665 Aurora Court Anschutz Cancer Pavilion
Aurora, CO 80045

UCHealth Cherry Creek Medical Center
100 Cook Street
Denver, CO 80206

UCHealth Cancer Center - Highlands Ranch
1500 Park Central Drive
Highlands Ranch, CO 80129

UCHealth Lone Tree Medical Center
9548 Park Meadows Drive
Lone Tree, CO 80124

Children's Hospital Colorado:
13123 East 16th Avenue
Aurora, CO 80045

Rocky Mountain Regional VA Medical Center:
1700 North Wheeling Street
Aurora, CO 80045-7211


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Information reviewed by Breelyn Wilky, MD, in February 2021.
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