PET/CT is usually not used for diagnosing colorectal cancer. Rather, PET/CT most often is used to determine the extent of cancer (staging) after cancer has been diagnosed. PET/CT is also frequently used for re-staging after treatment. PET/CT is the most powerful and accurate tool available for those two tasks.
Frequently colorectal cancer is treated with surgery. PET/CT can be used before surgery to guide the surgeon. Also, sometimes PET/CT reveals that the cancer has spread too much to be treated with surgery. This helps direct management of the cancer away from a futile surgical procedure, to a more appropriate therapy.
After treatment, PET/CT is a powerful tool for detecting recurrence. It is more accurate than the CEA blood test that is commonly used. PET/CT is covered by Medicare and some private insurers for this use (as well as the uses listed above). For more information, please consult your doctor.
Colorectal Cancer Case
Patient: 68yo male initially diagnosed with colon cancer 1999. The patient underwent surgery and chemotherapy. Patient now with rising CEA and CT with a solitary liver lesion in the right lobe Patient being considered for surgery. PET/CT was ordered to restage the patient.
Results: PET/CT revealed multiple tumors within the bones, liver and abdominal lymph nodes that were not seen with CT. PET/CT helped the patient avoid a futile surgery, and directed the patient to a more appropriate therapy.