Tests for Soft Tissue Sarcomas

If you have signs or symptoms that suggest you might have a soft tissue sarcoma , the doctor will likely need to do tests to find out if you have cancer.

Medical history and physical exam

The doctor will ask about your medical history, including your family history, to learn if you have any possible risk factors. You will also be asked about your symptoms, such as when they started and how long you’ve had them.

Imaging tests

Imaging tests use sound waves, x-rays, magnetic fields, or radioactive substances to create pictures of the inside of your body. Imaging tests may be done for a number of reasons, such as:

• To look at suspicious areas that might be cancer,
• To see if, and how far, cancer has spread
• To help determine if treatment is working

Plain x-ray

A regular x-ray of the area with the lump may be the first test ordered. A chest x-ray may be done after you are diagnosed to see if the sarcoma has spread to the lungs.

CT (computed tomography) scans

A CT scan uses x-rays to make detailed cross-sectional images of your body. This test is often done if the doctor suspects a soft tissue sarcoma in the chest, abdomen (belly), or the retroperitoneum (the back of the abdomen). This test is also used to see if the sarcoma has spread to the lungs, liver, or other organs.

CT scans might be used to guide a biopsy needle into a tumor inside the body — the chest or abdomen, for example. This is called a CT-guided needle biopsy. (See below for more on biopsy.) You lie on the CT scanning table while a radiologist moves a biopsy needle toward the tumor. CT scans are repeated until the doctors are sure the needle is within the tumor.

MRI (magnetic resonance imaging)

MRI uses radio waves and strong magnets instead of x-rays to take pictures of the body. MRI scans are often part of the work-up of any tumor that could be a sarcoma. They're often better than CT scans in evaluating sarcomas in the arms or legs.

MRI provides a good picture of the extent of the tumor. It can show your health care team many things about the tumor, like where it is, how big it is, and sometimes even the type of tissue it comes from (like bone, fat, or muscle). MRIs are also very helpful in examining the brain and spinal cord.

Ultrasound

Ultrasound uses sound waves and their echoes to produce pictures of parts of the body. A small instrument called a transducer sends out sound waves and picks up the echoes as they bounce off the organs. A computer then converts the echoes into an image on a screen.

Ultrasound may be done before a biopsy to see if a lump is a cyst, meaning if it has fluid in it and is likely not cancer, or if it's solid and more likely a tumor. This test is often not needed if a CT or MRI was done.

PET (positron emission tomography) scan

PET scans use a form of radioactive sugar that's put into the blood. Because cancers use glucose (sugar) at a higher rate than normal tissues, the radioactivity collects in the cancer. A scanner can then spot the radioactive deposits.

A PET scan is useful when your doctor thinks the cancer has spread but doesn't know where. It can be used instead of many different x-rays because it scans your whole body. Often the PET scan is used with a CT scan (called a PET/CT scan). This helps decide if changes seen on the CT scan are cancer or something else. PET isn't often used for sarcoma, but it can be helpful in some cases.

Biopsy

If a soft tissue sarcoma is suspected based on exams and imaging tests, a biopsy is needed to know for sure that it's a sarcoma and not another type of cancer or a benign (not cancer) disease. In a biopsy, the doctor takes out a small piece of the tumor. This tissue is looked at under a microscope and other lab tests may be done as well.

Several types of biopsies are used to diagnose sarcomas. Doctors experienced with these tumors will choose one, based on the size and location of the tumor. Most prefer to use a fine needle aspiration or a core needle biopsy as the first step. See Testing Biopsy and Cytology Specimens for Cancer to learn more about the types of biopsies, how the tissue is used in the lab to diagnose cancer, and what the results may show.

You might want to ask about your surgeon’s experience doing biopsies. Proper biopsy technique is a very important part of successfully treating soft tissue sarcomas. An improper biopsy can lead to tumor spread and problems removing the tumor later on.