Diagnosis
Soft-tissue sarcomas can be difficult to diagnose because they can form in many parts of the body. However, an accurate diagnosis of the specific type of sarcoma is essential before starting treatment. If you have symptoms, your doctor will conduct a physical exam and ask questions about your medical history. If your doctor suspects sarcoma, he or she may recommend any of the following procedures:
Imaging Tests
Your doctor may request any of the following imaging tests to determine the location and extent of the cancer, before or after a biopsy:
Chest X-Ray
X-rays use electromagnetic radiation to produce images of the inside of your body. Your doctor may order a chest X-ray to see whether the cancer has spread to the lungs.
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Ultrasound
During this procedure a transducer is placed on your skin. The transducer then bounces sound waves off of your internal organs in order to create echoes that form a picture.
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Computed Tomography (CT) Scan
For a CT scan, you lie flat on a table while a machine rotates around the body and takes pictures. A special dye may be injected into your veins and you may be asked to drink a special fluid in order to make the internal organs stand out. A CT scan reveals the presence of tumors and whether or not the cancer has spread to other parts of the body.
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Magnetic Resonance Imaging (MRI) Scan
Magnetic resonance imaging (MRI) uses radio waves and a strong magnet to create clear and detailed images of body parts. Radio waves are absorbed by the body and then released in a certain pattern, which is translated by a computer in order to show "slices" of the body.
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Positron Emission Tomography (PET) Scan
For a PET scan, the doctor injects a radioactive substance into the patient's bloodstream. This substance collects in diseased cells in the patient's body. The doctor then uses a PET scanner to detect these areas of radioactivity and to find the potential areas the cancer has spread to in the patient's body.
Biopsy
A biopsy is the only way to be certain that a tumor is a malignant sarcoma. Your doctor will remove a tissue sample from the tumor and have it examined under a microscope. Your doctor may request any of the following biopsy procedures, based on the size and location of the tumor:
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Fine Needle Aspiration (FNA)
Your doctor will use a very thin needle to extract cells from the tumor. Your doctor will then send this sample to a laboratory to be examined under a microscope to detect the presence of cancer cells. If this biopsy shows sarcoma, your doctor may order another biopsy with a larger tissue sample to confirm the diagnosis.
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Core Needle Biopsy
Your doctor will use a slightly larger needle to remove a cylinder of tissue from the tumor. Your doctor will then send this sample to a laboratory to be examined under a microscope for cancer cells. This is the most common method of biopsy for soft-tissue sarcomas.
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Incisional Biopsy
Your doctor will use a scalpel to remove part of the tumor for examination.
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Excisional Biopsy
Your doctor will use a scalpel to remove the entire tumor for examination.
Laboratory Tests
Your doctor or the doctor examining your biopsy (pathologist) may run any of the following tests on the biopsy sample removed to make a diagnosis:
Immunohistochemistry
Your doctor may treat your biopsy sample with special stains containing indicator antibodies. These substances react with certain types of cells present in sarcomas, and produce visible stains that can be seen under a microscope.
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Cytogenetics
Your doctor may examine your cancer cells for chromosome changes in order to determine the specific characteristics and subtype of your disease.
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Fluorescent in situ hybridization (FISH)
Doctors use this test to detect changes in the chromosomes and DNA of your biopsy sample. Your doctor will expose the sample to special dyes that will bind to specific parts of certain chromosomes. These dyes help your doctor detect any abnormalities in the chromosomes of the cells in your biopsy sample to help determine your type of sarcoma.
Polymerase Chain Reaction (PCR)
Doctors use this test to detect chromosome abnormalities that cannot be seen under a microscope because they are too small. This test is very sensitive and can detect these abnormalities even if there are very few cancer cells in the sample. This can help with determining your sarcoma subtype and selecting appropriate treatment.
Next Generation Sequencing
In some cases your doctor will send your tumor tissue for targeted sequencing where they look at multiple genes to detect abnormalities that might help match a new treatment to the abnormality present on your tumor.
