When doctors suspect sarcoma, they may use several tools to gather more information about the tumor and determine whether it’s cancer.
Soft Tissue Sarcoma Diagnosis & Grade
For soft tissue sarcomas, doctors may use magnetic resonance imaging (MRI), computed tomography (CT) scans, or positron emission tomography (PET) scans to create a picture of the inside of the body and see the tumor.
The only way to definitively diagnose sarcoma is to perform a biopsy—to remove cells from the tumor and examine them under a microscope. During this examination, doctors also evaluate how abnormal the cancer cells appear. This allows them to categorize the tumor as low grade or high grade. Low-grade sarcomas, although cancerous, are unlikely to spread to other parts of the body (though they may recur at the original site after treatment). High-grade sarcomas are more likely to spread to other parts of the body.
Bone Cancer Diagnosis & Grade
For bone cancer, doctors may suggest doing a blood test to determine the level of an enzyme called alkaline phosphatase. A high level may be found when there is a disease or tumor in a bone. High levels of this enzyme can also be found in children and adolescents with growing bones, so the test is not a reliable sign of bone cancer in young people. Doctors also use X-rays and other imaging tests, such as bone scans, MRIs, and PET scans to find out more about bone tumors. In any case, a biopsy is needed to confirm whether or not cancer is present.
The grade of a malignant (cancerous) bone tumor is based on how abnormal the cells appear under a microscope. A higher number indicates more abnormal cells; these tumors generally grow and spread more quickly than low-grade tumors.
Adults over the age of 40 who have a bone tumor or other bony abnormality that might be a tumor should be evaluated carefully to see whether they have primary cancer of their lung, kidney, breast, or prostate that may have spread to their bones. This means having a CT scan of the lungs and abdomen and a total body bone scan.
UW-OncoPlex is a diagnostic tool that uses genetic sequencing to look for mutations that cause cancer. These “genetic profiles” of cancer cells help doctors identify what mutations are driving tumors. Launched at Seattle Cancer Care Alliance in 2012, UW-OncoPlex allows doctors to better predict which therapies will be most effective in treating a patient’s cancer. With more than 60 types of sarcoma, information gathered through the UW-OncoPlex panels helps identify targeted therapies for sarcoma.