title: Utility of PET scans to predict disease relapse in pediatric patients with Hodgkin lymphoma.
abstract: BACKGROUND
  Positron emission tomography (PET) differentiates normal from abnormal cells based on metabolic activity. Numerous studies report that PET scan offers increased sensitivity, specificity and predictive values as compared to computed tomography (CT) in adult lymphoma patients.
  
  
  METHODS
  Twenty-three consecutive pediatric Hodgkin lymphoma (HL) patients were evaluated with PET scan either at diagnosis or during treatment, then at therapy completion and in follow-up.
  
  
  RESULTS
  Twenty two of the 23 patients had a negative PET scan at the end of therapy; however, ten later developed a positive scan for a total of 11 (47.8%) patients with a positive post treatment PET scan. Six tissue biopsies were performed in five patients; four specimens were negative for disease and two confirmed HL relapse. Six patients were monitored clinically and remained asymptomatic; four had resolution of abnormalities on repeat PET while two had persistently positive, but stable PET scan findings and continue to be in remission at 11 and 40 months following treatment. Twelve (52.2%) patients of the original cohort have had consistently negative PET scans and have not relapsed.
  
  
  CONCLUSIONS
  PET is a sensitive (100%), but not a specific (57.1%) method for evaluating post-treatment pediatric HL patients with a strong negative predictive value (NPV; 100%), but poor positive predictive value (PPV; 18.2%). We do not recommend treatment decisions be based solely on PET scan results.
authors.affiliation: Department of Pediatric Hematology/Oncology, Children's National Medical Center, Washington, District of Columbia 20010, USA. hmeany@cnmc.org
authors.forename: Holly J
authors.initials: HJ
authors.lastname: Meany
authors.forename: Vinod K
authors.initials: VK
authors.lastname: Gidvani
authors.forename: Caterina P
authors.initials: CP
authors.lastname: Minniti
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005189:False Positive Reactions; D005260:Female; D006689:Hodgkin Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D012008:Recurrence; D012074:Remission Induction; D012189:Retrospective Studies; D012680:Sensitivity and Specificity