Positron emission tomography-computed tomography (PET-CT) is the modern standard for staging Hodgkin Lymphoma and response assessment using Deauville criteria is robust, according to a study published online ahead of print in the journal Blood.1

Because international guidelines recommend that PET-CT replace CT in Hodgkin lymphoma, researchers sought to compare PET-CT with CT for staging and measure agreement between expert readers and local readers using the Deauville criteria to adapt treatment.

For the Response Adapted Therapy in Advanced Hodgkin Lymphoma (RATHL) trial, investigators staged patients using clinical assessment, CT, and bone marrow biopsy (RATHL stage).

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Patients were also staged using PET-CT, which was performed at baseline and after 2 chemotherapy cycles in a response-adapted design. PET-CT findings were then reported centrally by experts at 5 national core labs while local readers optionally scored PET-CT findings performed after 2 cycles of chemotherapy.

Results showed that RATHL stage and stage determined by PET-CT at baseline were the same in 938 (80%) patients. Researchers found that PET-CT upstaged 159 (14%) and downstaged 74 (6%) patients. PET characterization of lesions was the cause of discrepant findings for most.

The study also demonstrated that marrow biopsy upstaged 5 patients and contract-enhanced CT in bowel and/or liver or spleen upstaged 7.

The investigators determined that agreement on PET-CT findings after 2 cycles of chemotherapy amongst experts was very good and was good between experts and local readers.

The findings suggest that RATHL results can be translated into clinical practice.


  1. Barrington SF, Kirkwood AA, Franceschetto A, et al. PET-CT for staging & early response: results from ‘Response Adapted Therapy in Advanced Hodgkin Lymphoma’ (RATHL) (CRUK/07/033) [published online ahead of print January 8, 2016]. Blood. doi: 10.1182/blood-2015-11-679407.