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Sarcomas are a rare kind of tumor that forms in the cells that make up bone or connective tissue. They represent less than 1%  of all cancers and can occur in children or adults. Fortunately, most lumps that form in bones and connective tissue are harmless. 

At Yale Medicine, cancer physicians and surgeons strive to cure every case of sarcoma, while reducing treatment side effects and giving patients the best quality of life possible.

What are the types of sarcoma?

Sarcomas fall into two types: bone sarcomas and soft-tissue sarcomas. Bone cancer includes osteosarcomas, which often form in the ends of long bones like those in the arms and legs.

Soft-tissue sarcomas have several subclassifications, including liposarcomas (in fat tissue), rhabdomyosarcomas (usually a childhood tumor of connective tissues involved in muscle development), and gastrointestinal stromal tumors (in the stomach or small intestine). Soft-tissue sarcomas can also form in cartilage, nerves, fibrous tissue, blood vessels, and other connective tissue.

Ewing sarcoma can form in either bone or soft tissue, but usually arises in bone.

Sarcomas can form in children or adults, but different types are more common at different ages. Osteosarcomas, Ewing sarcomas, and rhabdomyosarcomas are usually diagnosed in children and young adults. Gastrointestinal stromal tumors are more common in adults. Other soft tissue sarcomas that arise in muscle or tendons occur across the age spectrum.

What are the symptoms of sarcoma?

Sarcomas can form all over the body. Depending on their types and locations, they can cause different symptoms or no symptoms at all. Many people with sarcomas will notice a lump or swelling somewhere on their body, or will have unexplained pain or warmth in a certain body part.

A sarcoma may cause pain or numbness if it grows large enough to press on surrounding nerves. For certain types of sarcomas, a bone that breaks for no reason may also be a warning sign.

What are risk factors for sarcoma?

There are few known risk factors for sarcomas. Unlike some other cancers, such lifestyle factors as smoking, drinking alcohol, or lack of exercise play no role in the chances of developing sarcomas.

The following, though, may increase risk:

  • Radiation for another form of cancer
  • Certain genetic mutations or syndromes
  • Exposure to such chemicals as vinyl chloride, arsenic, dioxin, and/or high doses of commercial herbicides

How are sarcomas diagnosed?

The first step in diagnosing a sarcoma is a complete physical exam, in which a doctor asks about symptoms and checks for unusual lumps or painful spots.

Then, the doctor may order X-rays, computed tomography (CT) scans, or magnetic resonance imaging (MRI) scans to get a better look at the bone or soft tissue. If those scans reveal an unusual mass, a biopsy is performed and a small tissue sample is removed, either through a surgical incision or a wide, hollow needle.

If cancer is determined, it is given a grade (from I to IV), depending on how aggressive it is and whether it has spread. More imaging tests, including CT, MRI, positron emission tomography (PET), and/or bone scans may be needed to complete the staging of the disease.

Sarcomas are also sometimes discovered when X-rays or MRIs are taken after an unrelated injury. Those scans may reveal a cancer that’s been there for some time but has not caused symptoms.

How are sarcomas treated?

Once a cancer has been diagnosed, doctors will decide on a treatment plan based on the type of sarcoma, its location, and its stage.

For most sarcomas, the tumor and some of the surrounding tissue will be removed surgically, making sure no cancer cells are missed. Surgeons will then reconstruct any healthy tissue that was disturbed.

For soft-tissue sarcomas, radiation therapy is often performed, too, either before or after surgery. It helps to ensure that the cancer cells are killed and don’t come back, and lets doctors do less extensive surgery than they’d have to otherwise. Radiotherapy is sometimes the primary local treatment (without surgery) for Ewings sarcoma in conjunction with chemotherapy. Osteosarcomas are rarely treated with radiotherapy.

If a soft-tissue sarcoma develops in a person’s arm or leg,  removing too much tissue could cause permanent damage and limit future use of the limb. “In that case, we try to preserve function by also treating with radiotherapy, which in turn allows the surgeon to perform a less radical procedure,” says Kenneth Roberts, MD, PhD, director of Pediatric Radiotherapy and the Sarcoma Program at Yale Medicine. “The two modalities work hand in hand to limit how much surgery is needed while still allowing for control of the tumor.”

At Yale Medicine, radiotherapy usually includes external beam radiation, in which the patient lies on a table and an X-ray beam is aimed at the tumor. Treatment sessions last a few minutes daily, five days a week, for several weeks.

A one-time treatment of internal radiation, called brachytherapy, may also be used. Small radioactive pellets are inserted into the body via a catheter and placed directly in or next to the tumor. Over a few minutes or days, the pellets give off radiation to a concentrated area, protecting the surrounding tissue.

Some patients may also benefit from chemotherapy, along with radiation and surgery.

Children with sarcomas are selectively treated with radiation, but care is taken to minimize negative effects on growth and development. 

What are potential side effects of treatment for sarcoma?

Today’s radiation treatments can target cancer cells specifically, while minimizing damage to surrounding tissue, so serious side effects are rare. But radiation can still cause such side effects as fatigue, nausea, and skin problems. It is more likely to cause long-term damage in children, so doctors must weigh the risks and benefits when treating young patients.

Chemotherapy can also cause such side effects as nausea and vomiting, hair loss, fatigue, and low blood counts. Most of those side effects go away after treatment stops.

How is Yale Medicine’s approach to treating sarcomas unique?

Patients at Yale Medicine are cared for by the multidisciplinary team of doctors in the Sarcoma Program at Smilow Cancer Hospital. “Yale Medicine has an outstanding team of radiation oncologists, medical oncologists, and surgeons,” says Dr. Roberts.

Research at our Cancer Center has dramatically improved the treatment for sarcoma in recent years. “Yale Medicine is at the forefront of being able to translate basic scientific findings into therapies that can really help our patients,” says Dr. Roberts. Some sarcoma patients qualify for clinical trials, which give them access to new treatment options not found at other hospitals.