A sarcoma is a form of cancer within the connective tissues in the body. Sarcomas are rare, but can arise anywhere in the body since the cells affected can be found in bones, nerves, muscles, tendons, fat, cartilage, blood vessels of the arms or legs, or other connective tissue locations within the body.
- Sarcomas are divided into two groups, soft tissue sarcoma and primary bone sarcoma, since they start in the cells that make up soft tissues or bones.
- Current estimates suggest sarcomas only make up 1% of all adult cancers and around 15% of all childhood cancers.
- Sarcoma is sometimes curable through surgical removal, and/or a combination of surgery and other cancer treatments.
- If not treated, a sarcoma can spread (metastasize) to other portions of the body.
As the name of the sarcoma implies, a bone sarcoma is a cancer that starts in the bone. Soft tissue sarcoma starts in other types of body tissue, like fat, muscle, nerves, and blood vessels .
There are over 100 different subtypes of soft tissue sarcoma, with the most common subtypes being:
- Liposarcoma: tumor of fat tissue
- Leiomyosarcoma: tumor of the smooth muscle
- Gastrointestinal stromal tumor (GIST): tumor that begin in nerve cells within the digestive system
- Undifferentiated pleomorphic sarcoma: tumors made up of cells that grow in multiple shapes and sizes
- Myxofibrosarcoma: tumor of the tissue that separates muscles from each other and from the surrounding skin
- Synovial sarcoma: tumor that occurs near large joints
- Malignant peripheral nerve sheath tumor (MPNST): tumor that occurs in the lining of nerves
All these sarcoma subtypes appear differently on examination and on imaging studies, grow at different rates, and have different responses to surgery, chemotherapy, immunotherapy, and radiation.
Sarcomas, like other cancers, are caused by gene changes or mutations in the tissue from which the tumor originates. These mutations occur at a low frequency, and if one is unlucky enough to have these mutations in genes that control cell growth, one can get a sarcoma.
Anything that increases the gene mutation rate can increase the risk of cancer. Some factors that may increase risk of sarcoma include:
- Family history of sarcomas
- Exposure to radiation therapy and certain chemics and carcinogens
- Genetic disorders (e.g., familial adenomatous polyposis (FAP), Gardner’s syndrome)
- Bone disorders (e.g., Paget's disease)
Still, the vast majority of sarcomas occur with no identifiable cause.
As there are many places a sarcoma can occur within the body, symptoms will vary depending on type and location.
Because a majority of the body’s connective tissue is in the arms and legs, the most common location of a sarcoma is in a limb; About half of all soft-tissue sarcomas occur in the extremities, while one-third of all cases begin in the abdomen (belly). In these areas, sarcomas often do not cause any symptoms until they grow large enough to create a noticeable lump or swelling.
In the abdomen or pelvis, sarcomas can grow to large sizes before they are noticed, forming a mass that one can feel or one that causes abdominal bloating, decreased appetite, or weight loss. Abdominal and pelvic tumors can also press on veins causing leg swelling or on nerves causing leg pain and numbness.
Other general symptoms of sarcoma may or may not include:
- Pain in affected area
- Weight loss
- Noticeable limp (if the sarcoma is located within the leg)
- Abdominal pain
- Blood in stools or vomit
Many sarcomas are initially diagnosed after they become large enough to be seen or felt on a physical exam, while others are picked up incidentally on imaging studies done for unrelated medical problems such as kidney stones or low back pain.
Imaging tests add more information to the diagnosis by giving a better sense of the size, location, and spread of the tumor. The preferred imaging test will depend on the type of sarcoma, but options include:
- X-rays: best for seeing bone sarcomas
- Ultrasounds: can help identify whether a lump is fluid-filled (and therefore not likely to be cancer) or a solid tumor
- CT (computerized tomography) scans: help identify soft-tissue sarcomas, particularly in the chest or abdomen
- MRIs (magnetic resonance imaging): Particularly good for identifying sarcomas in the arms and legs
- PET (positron emission tomography) scans: Useful for seeing if a cancer has spread to other parts of the body
Confirmation of a sarcoma diagnosis is done through a biopsy, which involves removing a sample of cells from the tumor and investigating them under a microscope.
The treatment of a soft tissue or bone sarcoma may include surgery, medical therapies (including chemotherapy, immunotherapy, and biological therapy), and radiation therapy. Each sarcoma subtype has different responses to surgery, medical therapy, and radiation therapy. Surgery is the best treatment option for most sarcomas, and sometimes chemotherapy and/or radiation therapy can be given to shrink the tumor or reduce the risk that the tumor comes back.
The goal of sarcoma surgery is to remove as much of the tumor as possible so that there are no cancer cells remaining that could cause the sarcoma to return. For sarcomas of the arms and legs, removing the tumor completely sometimes requires amputating the limb, though surgeons always look to avoid this if possible.
Radiation therapy involves directing high-energy beams (usually x-rays) to the sarcoma. The radiation kills cancer cells and is often given after surgery to destroy any remaining traces of the removed sarcoma. Sometimes radiation is given immediately after surgery, while the patient is still in the operating room--this is called Intraoperative Radiation Treatment, or IORT. Radiation therapy can also be used to shrink the tumor before surgery, making it easier to safely remove.
Proton Beam Radiation
Proton beam radiation therapy is a form of sarcoma treatment that uses protons rather than x-rays as the source of radiation. Proton beam radiation therapy has been shown to be particularly effective in the treatment of sarcomas that appear in the pelvis and back of the abdomen (known as the retroperitoneal area). Tumors in these locations can be difficult to fully remove with surgery, and because they’re often positioned close to x-ray-sensitive organs like the kidneys and liver, they are difficult to treat with traditional radiation therapy as well. For these tumors, pre-surgery treatment with proton beam radiation, followed by surgery and then an intraoperative boost of electron radiation has been shown to significantly reduce the chance that the sarcoma returns.
Chemotherapy is the use of medications to treat cancer. These medications are often delivered intravenously, though some may be given in pill form and taken by mouth. The use of chemotherapy drugs--and the specific drugs used--depend on the particular type of sarcoma being treated. Chemotherapy may be given before surgery to shrink the tumor, or in cases where surgery is not possible, it may be the primary form of treatment.
Targeted therapies are newer medications that act on more specific parts of the tumor than traditional chemotherapies. Some drugs shrink or slow tumor growth of sarcomas that cannot be removed with surgery.
The overall five-year survival rate for sarcoma is 65 percent. That means that, of all the people diagnosed with sarcoma, 65 percent are still alive five years after diagnosis. The National Cancer Institute gives more specific survival rates by using the following categories:
- Localized: 81 percent
- Localized means the cancer was only found in its original position within the body
- Regional: 56 percent
- Regional means the cancer spread only to nearby lymph nodes or close portions of the body
- Distant: 15 percent
- Distant means the cancer spread to distant portions of the body such as the lungs
Survival rates are determined based on how far the cancer has spread, but do not include personalized data per patient. The specific tumor location, treatment response, as well as a patient’s age and overall health, also affect an outlook. Additionally, sarcoma treatments are steadily improving. The NCI data is based on patients diagnosed and treated at least five years ago.
If you or your loved one have been diagnosed with a soft tissue sarcoma, the Sarcoma Care Program at Columbia can help. Our surgeons have the experience and expertise to bring you the best quality care, as safely as possible, and as part of the Herbert Irving Comprehensive Cancer Center, access to all the latest resources and options available. Our team features pioneers in the areas of surgical oncology and sarcoma care, including leaders in the use of proton beam radiation and surgery to safely treat particularly difficult tumors.
To make a surgical appointment with the Sarcoma Care Program, please call us at (212) 305-0273 today or request an appointment online today .