title: Paediatric and adolescent Hodgkin lymphoma: information derived from diffuse organ uptake of 18 F-fluorodeoxyglucose on pre-treatment and on interim PET/CT.
abstract: OBJECTIVE
  To evaluate, in children with Hodgkin lymphoma (HL), the frequency and intensity of visually diffuse FDG uptake by selected organs at baseline (bPET) and on interim PET/CT (iPET), and to evaluate the relation between FDG uptake, metabolic response and evolution of the disease with treatment.
  
  
  METHODS
  Thirty children with HL had bPET and then iPET after two cycles of treatment, which were blind-read retrospectively. Excluding sites with focal uptake, diffuse FDG uptake by thymus, bone marrow at iliac crests, liver, spleen, and the spinal cord at the 12th thoracic vertebra (Th12) was evaluated visually using a three-point scoring method and semiquantitatively by measuring SUVmax. Visualisation of activated brown adipose tissue (BAT) was also quoted. Five children had refractory HL. Recurrence-free survival was determined for each patient. Nine patients relapsed; in 21 non-relapsing patients, the median follow-up period was 43 months (range: 28-61).
  
  
  RESULTS
  On bPET, the rate of diffuse and intense (visual score = 3) FDG uptake was 48 % in the spleen, 43 % in the spinal cord at Th12, 37 % in bone marrow, 21 % in the thymus and 7 % in BAT. At least one of those sites showed diffuse and intense FDG uptake in 77 % of patients. On iPET, a significant decrease in SUVmax was observed in thymus, iliac crest bone marrow and spleen, but not in spinal cord. In contrast, the FDG uptake by the liver significantly increased. The absence of SUVmax increase in the liver between bPET and iPET was the best criterion to predict a refractory disease (PPV = 55 %, NPV = 100 %). Its area under ROC (AUC) was 0.9 vs. 0.73 for five-point Deauville criteria. For prediction of relapse, two criteria were derived from the evolution of diffuse uptake between bPET and iPET: no increase in liver uptake and an increase > 5 % in spinal cord uptake. As compared with 13 patients who matched none of those criteria, the hazard ratio (HR) for relapse was 2.1 in 13 patients who matched one criterion, and 10.3 in four patients who matched both (Kaplan-Meier analysis p = 0.005).
  
  
  CONCLUSIONS
  Diffuse and intense FDG uptake by organs is frequent in children with HL on bPET. On iPET, it is frequently reduced in all sites except the liver, which may pose problems for visual quotation of the FDG intensity of HL foci. The variation of SUVmax between bPET and iPET permitted us to achieve a prediction of refractory or relapsing HL that was at least as effective as using criteria based on FDG uptake by the HL lesions. The results of this retrospective pilot study need further validation.
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP & Université Pierre et Marie Curie, Paris, France. jorgovlinda@gmail.com.|Department of Nuclear Medicine, Semmelweis University, Budapest, Hungary. jorgovlinda@gmail.com.
authors.forename: Linda
authors.initials: L
authors.lastname: Jorgov
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP & Université Pierre et Marie Curie, Paris, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Montravers
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP & Université Pierre et Marie Curie, Paris, France.|Department of Nuclear Medicine, Comenius University & St. Elisabeth Oncology Institute, Bratislava, Slovakia.
authors.forename: Sona
authors.initials: S
authors.lastname: Balogova
authors.affiliation: Department of Paediatric Haematology & Oncology, Hôpital Trousseau AP-HP & Université Pierre et Marie Curie, Paris, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Ragu
authors.affiliation: Department of Paediatric Oncology, Institut Curie, Paris, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Pacquement
authors.affiliation: Department of Paediatric Haematology, Hôpital Robert Debré, AP-HP, Paris, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Leblanc
authors.affiliation: Department of Children and Adolescent Cancer, Institut Gustave Roussy, Villejuif, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Abbou
authors.affiliation: Department of Radiology, Hôpital Trousseau, AP-HP & Université Pierre et Marie Curie, Paris, France.
authors.forename: Hubert
authors.initials: H
authors.lastname: Ducou-Lepointe
authors.affiliation: Department of Paediatric Haematology & Oncology, Hôpital Trousseau AP-HP & Université Pierre et Marie Curie, Paris, France.
authors.forename: Judith
authors.initials: J
authors.lastname: Landman-Parker
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP & Université Pierre et Marie Curie, Paris, France.
authors.forename: Jean-Noёl
authors.initials: JN
authors.lastname: Talbot
mesh_terms: D000293:Adolescent; D001692:Biological Transport; D002648:Child; D002675:Child, Preschool; D004058:Diffusion; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006689:Hodgkin Disease / Q000188:drug therapy* / Q000378:metabolism* / Q000628:therapy; D006801:Humans; D008297:Male; D010865:Pilot Projects; D000072078:Positron Emission Tomography Computed Tomography
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: FDG PET/CT; Interim response evaluation; Paediatric Hodgkin’s lymphoma; Refractory; Relapse