If your provider would like to further investigate the possibility of sarcoma, one or more of the following diagnostic procedures may be performed.
A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a reliable diagnosis. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease.
There are different types of biopsies. For a needle biopsy, a doctor removes a small sample of tissue from the tumor with a needle-like instrument—usually a core needle biopsy and, less often, a thin needle biopsy. This may be performed with the help of ultrasound, CT scan, or MRI to precisely guide the needle into the tumor. In an incisional biopsy, a surgeon cuts into the tumor and removes a sample of tissue. In an excisional biopsy, the surgeon removes the entire tumor. Second surgeries are often needed after an excisional biopsy because the tumor may not have been completely removed. Because STS tumors are uncommon and there are many different types of STS, it is important to have an expert pathologist review the sample of tissue removed to appropriately diagnose a sarcoma. It is important for surgeons who have expertise in sarcoma to perform the surgery.
COMPUTED TOMOGRAPHY (CT) SCAN
A CT Scan creates a 3-dimensional picture of the inside of the body using x-rays taken from different angles. A computer combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. A CT scan can be used to measure the tumor’s size. Sometimes, a special dye called contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein and/or be a liquid the patient must drink.
MAGNETIC RESONANCE IMAGING (MRI)
An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. MRI can be used to measure the tumor’s size. A special dye called a contrast medium is given before the scan to create a clearer picture. This dye can be injected into a patient’s vein. MRI is a key test for doctors to decide whether a biopsy is necessary in cases of possible STS as well as to guide any surgical procedure. An MRI is generally viewed as necessary before any surgical procedure is performed.
Your doctor or the pathologist looking at the sarcoma may recommend running laboratory tests on a tumor sample to identify specific genes, proteins, and other factors unique to the tumor. Results of these tests will help decide what the treatment should be, because each sarcoma can be as different from one another as breast cancer is different from colon cancer.
POSITRON EMISSION TOMOGRAPHY (PET) SCAN
A PET scan is usually combined with a CT scan (see above), called a PET-CT scan However, you may hear your doctor refer to this procedure just as a PET scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive sugar substance is injected into the patient’s body. This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the inside of the body. This technique can be used to look at both the tumor’s structure and how much energy is used by the tumor and normal tissues. This information can be helpful in planning treatment and evaluating how well treatment is working, but it is usually not be performed in all cases of known or suspected STS.
An ultrasound uses sound waves to create a picture of the internal organs.
An x-ray is a way to create a picture of the structures inside of the body, using a small amount of radiation. X-ray is particularly useful for bone sarcomas, but less valuable for soft tissue sarcomas.