FDG-PET stands for fluorodeoxyglucose positron emission test. It is a radiologic study that uses information about the metabolism or activity of tumors to determine the extent a cancer has spread. A PET scan is done by labeling glucose (or sugar) molecule with a radioactive tag and then scanning for where these molecules show up in the body. Highly metabolic or active spots are suspicious for being cancerous, although there are areas, such as the kidney or bladder, that routinely show activity as well.
Oftentimes, PET scans are combined with computed tomography (CT) to help give both a structural and functional assessment of a tumor. For instance, an area of activity on a PET scan appears as a blurry area on the outline of your body. Adding a CT scan allows your doctor to locate the area on a PET scan to see if there is a growth or tumor that corresponds to that activity. The role of PET scanning in endometrial cancer is not clear, as it is not a good test to determine how deeply involved an endometrial cancer is.
It can determine if there are sites of activity outside of the pelvis, which is helpful in making the treatment plan. PET scans can be done to see if your cancer has become metastatic or has recurred. There are ongoing studies looking at the role of PET scans in uterine cancer. Over time, it is likely to become a well-accepted and frequently performed test for women with cancer of the uterus suspected of having disease beyond the pelvis.
At the time of this writing, there is no indication to order a PET scan prior to surgery for endometrial cancer. Often just an ultrasound is done pre-operatively. Sometimes a CT scan of the abdomen and pelvis will be ordered to look for enlarged lymph nodes; this is particularly useful in Type II cancers, which are more likely to go to the lymph nodes.