What Does Deauville Score Mean?

The Deauville score is a simple 1-to-5 scale. Doctors use it to read PET scans in people being treated for lymphoma. It measures how much of the radioactive tracer, FDG, has built up in areas of known or suspected lymphoma. That uptake is compared with two reference points inside your own body: the liver, and an area in the chest called the mediastinal blood pool.

Using your own body as the reference, instead of a fixed number, is the key idea behind the scale. It corrects for the fact that PET scanners and patients vary, which raw uptake numbers do not always account for well on their own.

A score of 1 means no uptake at all in the area being watched. A score of 2 means uptake is present but lower than the blood pool in the chest. A score of 3 means uptake is higher than the blood pool but no higher than the liver. A score of 4 means uptake is clearly higher than the liver. A score of 5 means a large increase in uptake, new areas of disease, or both.

Scores of 1 and 2 are generally read as a complete response to treatment. A score of 3 is also often treated as a complete response, especially on scans taken partway through treatment. Scores of 4 and 5 point toward disease that is still active or has come back.

The same score can mean different things depending on when the scan was taken. An interim scan, done partway through treatment, is read somewhat differently from an end-of-treatment scan, done once therapy is finished. Some lymphoma subtypes and treatment protocols also define what counts as a positive or negative result slightly differently. This is one reason your oncologist reads your Deauville score alongside exactly where you are in treatment, not as a number alone.

For some lymphoma types, an interim Deauville score can change the treatment plan mid-course. A low score partway through treatment sometimes supports finishing the planned regimen, or occasionally allows less intensive treatment afterward. A high interim score may prompt a change in chemotherapy, additional treatment, or a closer look with a biopsy to confirm what the scan shows. At the end of treatment, the score helps determine whether treatment is complete or whether additional therapy, such as radiation, is needed.

A Deauville score does not replace the rest of your evaluation. It does not stand in for your symptoms, your physical exam, your bloodwork, or a biopsy when one is needed to confirm what the scan shows. It also should not be read without knowing whether the scan was interim, end-of-treatment, or a later follow-up scan, since the same number carries different weight at each of those points.

The Deauville score itself is not an emergency finding. It is a planned part of monitoring lymphoma through treatment. What matters is following up with your oncology team promptly once results are available, since a high score sometimes changes the plan for your next treatment cycle.

• What was my Deauville score, and was this an interim or end-of-treatment scan?
• What cutoff does my treatment protocol use to define a good response?
• Does this score change my treatment plan going forward?
• When will the next scan happen, and what would it need to show?

Even with the liver and blood-pool comparison built in, some variation still exists. Scanner calibration can shift a reading slightly. So can the timing after the tracer injection. A reader's own judgment plays a role too. All of these can nudge a borderline case toward one score or the next. This is why major lymphoma centers often use two readers. Two nuclear medicine or radiology specialists independently review important scans. If your score sits right on the line between a low and high number, ask whether the scan was double-checked.

• The ASCO Post — Standardizing the Interpretation of PET Scans: An INR Equivalent
• National Cancer Institute — Diagnosis and Staging
• Staging and response assessment of lymphoma: a brief review of the Lugano classification and the role of FDG-PET/CT — PMC (NIH/NLM)