Sarcomas are rare cancers that develop from connective tissues (stroma) of the body such as fat, muscles, nerve tissue, fibrous tissues or blood vessels. There are many different types of sarcoma, based on the type of tissue in which they originate. Some sarcomas may even come from stem cells, or cells that have not formed into a specific type of tissue yet.
Unlike carcinomas that are very common and arise from epithelial cells (cells that make up tissue in organs such as the colon and lung), sarcomas account for just 1% of cancers in adults.
Some of the most common types of sarcoma and its tissue of origin include:
|Leiomyosarcoma||Smooth muscle (causes contraction of intestines, blood vessels, etc.)|
|Fibrosarcoma||Fibrous tissue (tendons or ligaments)|
|Gastro-Intestinal Stromal Tumor(GIST)||Specialized neuro-muscular cells of the digestive tract|
|Peripheral Nerve Sheath Tumors||Cells that wrap around nerve endings|
|Undifferentiated pleomorphic sarcoma||Unknown; May be tumor of stem cells|
Risk Factors include:
The cause of sarcomas is unknown. You may have a higher risk for developing sarcoma, however, if you have
- A certain genetic predisposition
- Exposure to chemotherapy or radiation
- A compromised immune system
- Come in contact with chemical carcinogens
- Chronic irritation
Sarcomas vary greatly in their aggressiveness, and their ability to spread or metastasize to other parts of the body. The best predictor of the behavior of a sarcoma is its “grade.” Low grade sarcomas are slow growing tumors, and generally tend to stay in the part of the body where they originated. High grade sarcomas are more aggressive, and are more likely to grow into surrounding structures; they can also metastasize, or spread, to other parts of the body. Intermediate grade sarcomas can be variable, but are less likely to metastasize than high grade sarcomas.
Staging for sarcoma can be complicated, and usually depends on the size and grade of the tumor, and whether or not it has spread to other parts of the body. Generally, high grade and larger tumors are staged higher than low grade, smaller tumors.
Symptoms and Tests
A soft tissue sarcoma usually produces no signs and symptoms in its early stages. Determining whether a mass or tumor is benign (non-cancerous) or malignant (a sarcoma) can be challenging, and often requires a biopsy for confirmation. The size and location of a soft tissue mass will help determine whether or not a biopsy is needed or not. Fortunately, soft tissue masses are usually benign.
We recommend evaluation for any lump that is:
- Greater than 5 cm in diameter (the size of a golf ball)
- Increasing in size
- Causing pain or other symptoms
- Growing in a scar where another tumor was removed or surgery performed
- In a muscle or deeper (rather than just below the skin)
- Has concerning appearance on an x-ray
The tests used for sarcoma vary greatly from case to case. Some may require a CT scan or MRI, while others may require a PET scan. These are used to determine the size and extent of the sarcoma, and to see if it has spread to other areas of the body. Your physician may also want to perform a biopsy, or examine a piece of the tumor under the microscope, prior to surgery. Biopsies are often used not only to obtain a diagnosis, but also for surgical planning and to determine whether radiation may be useful. In some cases, biopsy is not required prior to surgery. Biopsies may be performed in the office or by radiologists, depending on the circumstances.
The treatment of a sarcoma depends on the type, the location, the size and the extent to which it involves adjacent or vital structures. Surgical resection, or complete removal of the sarcoma by a surgical oncologist, is an essential part of any curative treatment. Radiation may be used prior to surgery, particularly for larger sarcomas of the extremity, or following surgery. This is used to decrease the size of the tumor prior to operating, or to allow preservation of important structures near the tumor, such as bone or nerves. Chemotherapy is used less frequently in the treatment of sarcomas, and generally limited to treatment of sarcomas that have metastasized. It is also sometimes used in conjunction with radiation.
Individualized treatment for each patient is determined after discussion at our bi-weekly, multidisciplinary conference, and tailored by the team of specialists to maximize cure rates, and minimize permanent dysfunction. Because sarcomas are so rare, they are best treated by a multidisciplinary team comprised of surgical oncologists, medical oncologists and radiation oncologists who specialize in this type of cancer.