This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on June 6, 2022.
A thorough and accurate cancer diagnosis is the first step in developing a soft tissue sarcoma treatment plan. During the diagnosis process, the care team performs a complete array of diagnostic tests and thoroughly reviews the patient's medical records and health history. The care team will also likely conduct a physical exam. This information helps the care team formulate treatment recommendations tailored to each individual patient.
The most common procedures used for diagnosing soft tissue sarcoma include those listed below.
The two most common biopsy techniques used for performing a soft tissue sarcoma biopsy are: needle biopsy and open surgical biopsy.
Needle biopsy: For this procedure, the doctor numbs the area of the planned biopsy with a local anesthetic before inserting a needle into the tumor to retrieve a sample of cells. A CT scan or ultrasound scan may be used to help guide the biopsy needle, especially if the lump is not near the surface of the body. Since there are so many types of sarcomas, a large “core” needle is used whenever possible, as this allows for a larger tissue sample. A needle biopsy may be especially useful for tumors that are hard to reach, such as a retroperitoneal sarcoma (a sarcoma located deep within the abdomen or pelvis) or a sarcoma deep within the thigh.
Surgical biopsy: An open surgical biopsy is only performed by an experienced surgical oncologist who has worked with sarcomas before. This procedure is usually performed under general anesthesia, because the surgeon must remove a relatively large sample of the tumor. With soft tissue sarcomas, the surgeon must be careful not to disrupt the tumor, as it could cause the cancer cells to spread. A surgical biopsy for soft tissue sarcoma takes careful planning, and there are two important steps that the surgeon takes:
CT scans: CT scans are useful when making the initial soft tissue sarcoma diagnosis, and to see if the cancer has spread to other areas of the body. CT scans also may be used to guide a biopsy needle.
MRIs: MRIs may help outline a tumor in the soft tissues, and may also help determine if cancer cells have spread.
PET scans: Because PET scans are very sensitive but don't show much detail, they often are performed in combination with a CT scan (called PET/CT).
Ultrasounds: Ultrasound scans may be used to provide information about a tumor or surrounding tissues and organs, and to precisely locate the position of a tumor in order to guide a needle biopsy.
X-rays: The lungs are a common location for soft tissue sarcomas to metastasize (spread). Therefore, X-rays of the chest may be taken to see if the cancer has spread to the lungs.
Laparoscopic ultrasound and laparoscopic biopsies may also be performed by the surgeon to diagnose and stage soft tissue sarcoma. For tumors located within the abdomen, a laparoscopic procedure is sometimes used to diagnose or stage the extent of disease. During laparoscopy, the surgical oncologist will make one or more small incisions in the abdomen and insert a video camera and other special surgical instruments.
Next topic: How is soft tissue sarcoma treated?