This article is the part of a monthly series of stories focused on cancer issues. Denver7 is proud to partner with the American Cancer Society,Cancer Support Community,Colorado Cancer Coalitionand Sarah Cannon Cancer Institute at HealthONEto bring you these stories, tips and resources.
DENVER — Sarcoma is a rare type of cancer that arises in the musculoskeletal system. Unlike carcinoma — the most common type of cancer, which arises in organs such as breasts, prostates and the gastrointestinal tract — sarcoma is generally less understood, and the rarity of sarcoma can make it more difficult to recognize and diagnose. Here's what you should know about sarcoma.
Different types of sarcoma
Cancer is named for the place where it starts, even if it metastasizes, or spreads, to other parts of the body. For example, lung cancer is still lung cancer even if spreads to nearby lymph nodes or the adrenal glands.
Sarcoma is a general term for a group of about 70 different types of cancers that start in mesenchymal cells, which are cells that develop into connective or lymphatic tissue and blood vessels.
"Sarcoma is a cancer that arises in the musculoskeletal system, in the connective tissue of the body, including bone, muscle, fatty tissue and nerve tissue," said Dr. Daniel Lerman, an orthopedic oncologist with the Institute for Limb Preservation at Presbyterian/St. Luke's Medical Center, a part of Sarah Cannon Cancer Institute and HCA Healthcare.
Sarcomas can occur anywhere in the body but are most common in the arms, legs, chest and abdomen. Sarcomas are grouped into two main types: bone sarcoma and soft tissue sarcoma. There are about 65 different subtypes of soft tissue sarcoma and three main subtypes of bone sarcoma: chondrosarcoma, osteosarcoma and ewing sarcoma.
Signs and symptoms
One of the most common signs of bone sarcoma is pain that's more evident when you're at rest or trying to sleep, Lerman said. Alternatively, soft tissue sarcomas are usually painless, even when they grow larger.
"We occasionally see pain with soft tissue sarcomas that arise around specific joints in the body, but that's likely due to discomfort in the joint because of the mass, and not pain from the mass itself," he said.
If someone notices a growing mass on the body, that could be a sign of soft tissue sarcoma.
Causes and risk factors
According to the American Cancer society, a risk factor is anything that changes the chance of getting a disease like cancer. Different cancers have different risk factors. For example, unprotected exposure to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung and many other cancers. However, risk factors don’t tell us everything. Having one risk factor or many doesn’t mean someone will get the cancer. Also, many people get cancer without having a risk factor.
Still, scientists have found a few risk factors that make a person more likely to develop soft tissue sarcomas:
Radiation exposure accounts for less than 5% of sarcomas. But patients might develop sarcomas from radiation given to treat other cancers, like breast cancer or lymphoma. The sarcoma often starts in the part of the body that was treated with radiation. The average time between the radiation treatments and the diagnosis of a sarcoma is about 10 years.
Radiation therapy techniques have improved steadily over several decades. Treatments now target cancers more precisely, and more is known about selecting radiation doses. These advances are expected to reduce the number of cancers caused by radiation therapy. But because these cancers take so long to develop, the results of these changes may not be seen for a long time. Still, radiation therapy is used only when its benefits — like improved survival rate and relief of symptoms — outweigh its risks. To learn more, see Second Cancers in Adults.
Family cancer syndromes
Family cancer syndromes are disorders caused by gene defects, or mutations, that people are born with — and often inherited from a parent — that are linked to a high risk of getting certain cancers. Some family cancer syndromes increase a person's risk of developing soft tissue sarcomas.
Damaged lymph system
Lymph is a clear fluid containing immune system cells that's carried throughout the body by a series of lymph vessels. These vessels connect lymph nodes, which are small bean-shaped collections of immune system cells.
When lymph nodes have been removed or damaged by radiation therapy, lymph fluid can build up and cause swelling. This is called lymphedema. Lymphangiosarcoma, a malignant cancer tumor that develops in lymph vessels, is a very rare complication of chronic lymphedema.
Exposure to vinyl chloride, a chemical used in making plastics, is a risk factor for developing sarcomas of the liver, but it hasn't been proven to cause soft tissue sarcomas. Arsenic has also been linked to a type of liver sarcoma but not soft tissue sarcoma. Exposure to dioxin and to herbicides that contain phenoxyacetic acid at high doses, such as might occur in people who work on farms, may also be risk factors, but this isn't known for certain. There's no evidence that herbicides, which are weed killers, or insecticides at levels encountered by the general public cause sarcomas.
Men and women develop sarcoma equally, although it represents only about 1% of cancers in adults. However, sarcoma accounts for 15% of childhood cancers. "Adults get more cancer, so it's proportionally less common," Lerman said. "Kids get less solid cancers, so proportionally osteosarcoma is more common in children. Adults get more solid cancers in other tissue sites."
Soft tissue sarcomas are typically treated with a combination of radiation therapy, surgery and sometimes chemotherapy. For bone sarcoma, the main treatment is surgery and possibly chemotherapy, depending on the subtype.