UNASSIGNED: International guidelines recommend PET-CT should replace CT in @entity978 ( @entity978 ). The aims of this study were to i) compare PET-CT with CT for staging and ii) measure agreement between expert and local readers, using a five-point scale (Deauville criteria), to adapt treatment in a clinical trial 'Response Adapted Therapy in Advanced @entity978 ' (RATHL) www. @entity5 .gov/clinicaltrials, reference NCT00678327. @entity1 were staged for the trial using clinical assessment, CT and bone marrow biopsy (RATHL stage). PET-CT was performed at baseline (PET0) and after 2 chemotherapy cycles (PET2) in a response-adapted design. PET-CT was reported centrally by experts at 5 national core labs. Local readers optionally scored PET2 scans. The RATHL and PET-CT stages were compared. Agreement amongst experts and between expert and local readers was measured. RATHL and PET0 stage were concordant in 938 (80%) @entity1 . PET-CT upstaged 159 (14%) and downstaged 74 (6%) @entity1 . Upstaging by extranodal disease in bone marrow (92), lung (11) or multiple sites (12) on PET-CT accounted for most discrepancies. Follow-up of discrepant findings confirmed the PET characterisation of lesions in the vast majority. Five @entity1 were upstaged by marrow biopsy; 7 by contrast-enhanced @entity409 or spleen. PET2 agreement amongst experts (140 scans) with kappa (95% CI) of 0.84 (0.76 - 0.91) was very good and between experts and local readers (300 scans) at 0.77 (0.68-0.86) was good. These results confirm PET-CT as the modern standard for staging @entity978 and that response assessment using Deauville criteria is robust enabling translation of RATHL results into clinical practice.

PET-CT for staging _ early response: results from 'Response Adapted Therapy in Advanced XXXX ' (RATHL) (CRUK/07/033).

@entity5 :: ('MESH:D009369', 'Disease') :: ['cancer'] @entity1 :: ('9606', 'Species') :: ['Patients', 'patients'] @entity978 :: ('MESH:D006689', 'Disease') :: ['HL', 'Hodgkin Lymphoma'] @entity409 :: ('MESH:D008107', 'Disease') :: ['CT in bowel and/or liver']
@entity978 :: (MESH:D006689,Disease) :: ['Hodgkin Lymphoma']
