PET-CT Scans: When to get one

It’s hard to predict and prevent cancer recurrence (the return of cancer during remission), but your oncologist can help you develop a plan to be as healthy as possible. Part of that plan may include imaging tests called PET or PET-CT scans to check for signs of cancer recurrence, but research shows you may not need them if you don’t have symptoms.

According to the American Society of Clinical Oncology, the benefits of PET or PET-CT scans often do not outweigh the risks.

Risks of PET-CT Scans

PET-CT scans are not useful to patients who do not have symptoms

If you have completed cancer treatments and do not have symptoms of recurring cancer, PET-CT scans are not proven to improve your quality of life or help you live longer. Instead, the American Society of Clinical Oncology recommends other methods to track your health status:

Know what symptoms of cancer recurrence to watch out for. The American Cancer Society suggests telling your doctor immediately if you experience any of the following symptoms:

Return of cancer symptoms you had before
Unusual pain that’s unrelated to injury
Easy bleeding or unexplained bruising
Rashes or allergic reactions
Chronic cough or shortness of breath
Frequent headaches
Chills or fever
Blood in your urine or stools
New lumps and bumps with no known cause
Digestive symptoms such as nausea, vomiting, loss of appetite, diarrhea or difficulty swallowing
Get regular checkups and physicals
Ask your doctor if other, less invasive scans are more appropriate (e.g., a mammogram to check for recurring breast cancer)

PET-CT scans expose you to a high level of radiation

A single PET-CT scan exposes you to 25 mSv of radiation. That’s the equivalent of about 2,500 X-rays. Because we know that radiation can be harmful in large amounts, it’s important to get imaging tests that use radiation only when necessary.

PET-CT scans can lead to unnecessary healthcare costs

PET-CT scans can cost thousands of dollars depending on the facility. and some insurance companies will not cover routine PET-CT scans for patients who do not have symptoms of recurring cancer. On rare occasions, PET-CT scans may also produce a false-positive result (an indication that a condition is present when it really isn’t), which can lead to additional costs.

When are PET-CT scans appropriate?

Although there are risks involved with PET-CT scans, it doesn’t mean these scans aren’t appropriate and useful in the right situations. PET-CT scans can:

See if/how well cancer treatment is working
Help your doctor plan radiation therapy
Discover the right location for a biopsy

If your doctor suspects cancer recurrence based on your symptoms or a physical exam, then a PET-CT scan may be the next appropriate step.

You can’t prevent cancer recurrence, but you can take steps to be as healthy as possible by eating a healthy diet and being physically active. Remember that cancer affects each person differently and you should work with your doctor to determine the most effective course of action.