title: PET-adapted omission of radiotherapy in early stage Hodgkin lymphoma-a systematic review and meta-analysis.
abstract: BACKGROUND
  Hodgkin lymphoma (HL) is one of the most common malignancies in young adults and one of the most curable cancers worldwide. With interim PET-scan, HL treatment is in the process of being modified: a negative or positive interim PET separates good and poor responders to initial therapy; therefore, deescalated or escalated additional treatment is currently being evaluated in clinical trials.
  
  
  METHODS
  The Cochrane Library, MEDLINE and conference proceedings were searched until 05.2015 for randomized controlled trials (RCTs) comparing FDG-PET-adapted therapy to standard treatment in untreated early stage HL patients with a negative PET-scan. Two review authors independently screened search results and extracted relevant study data. Hazard ratios (HR) were used for time-to-event data and risk rations (RR) for dichotomous data, with 95% confidence intervals (CI). If trials were considered sufficiently clinically homogenous, fixed-effect model was used to pool data.
  
  
  RESULTS
  Three RCTs involving a total of 1480 participants were included in the meta-analysis. Only one trial provided data for OS, without evidence for a difference between both arms (HR 0.51; 95% CI 0.15-1.68). All three trials assessed progression free survival, which was inferior in the PET-adapted arms (without radiotherapy) compared to the standard treatment arms (HR 2.40; 95% CI 1.63-3.53). Adverse events were reported in one study only, without evidence for a difference between both arms. There were no data on long-term adverse events, quality of life and treatment-related mortality available
  
  
  CONCLUSIONS
  To date, no robust data on survival and adverse events are available. However, this systematic review found that PFS was significantly decreased in the PET-adapted treatment arm (without radiotherapy) in early stage HL patients.
authors.affiliation: University Hospital of Cologne, Germany.
authors.forename: Marie T
authors.initials: MT
authors.lastname: Sickinger
authors.affiliation: University Hospital of Cologne, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: von Tresckow
authors.affiliation: University Hospital of Cologne, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Kobe
authors.affiliation: University Hospital of Cologne, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Borchmann
authors.affiliation: University Hospital of Cologne, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Engert
authors.affiliation: University Hospital of Cologne, Germany. Electronic address: nicole.skoetz@uk-koeln.de.
authors.forename: Nicole
authors.initials: N
authors.lastname: Skoetz
mesh_terms: D016208:Databases, Factual; D006689:Hodgkin Disease / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D049268:Positron-Emission Tomography; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic
keywords: Early stage Hodgkin lymphoma; Meta-analysis; PET; Systematic review