title: Assessment of metabolic response to radioimmunotherapy with 90Y-ibritumomab tiuxetan in patients with relapsed or refractory B-cell non-Hodgkin lymphoma.
abstract: OBJECTIVE
  To prospectively compare the assessment of metabolic response to yttrium 90 ((90)Y)-ibritumomab tiuxetan radioimmunotherapy (RIT) by using fluorine 18 ((18)F) fluorodeoxyglucose (FDG) combined positron emission tomographic-computed tomographic (PET/CT) imaging at 2 and 6 months to determine the most appropriate time to detect therapeutic response in refractory non-Hodgkin lymphoma (NHL) patients treated with RIT.
  
  
  METHODS
  The ethical committee of the university approved the protocol and all patients signed informed consent. Twenty-three consecutive patients (10 women, 13 men; mean age, 51.8 years +/-7.3 [standard deviation]) treated by using RIT for relapsed or refractory follicular NHL were enrolled. For all patients, (18)F FDG PET/CT scanning was performed at baseline and at 2 and 6 months after RIT. Response was assessed by using the International Workshop Criteria (IWC) and revised criteria (IWC + PET) as well as the criteria of the European Organization for Research and Treatment of Cancer. One-way analysis of variance for repeated measures, receiver operator curve analysis, and Kaplan-Meier curves were used for statistical analysis.
  
  
  RESULTS
  PET/CT performed at 2 months revealed complete (n = 12) or partial (n = 4) metabolic response in 16 of 23 patients with complete or partial clinical response. These findings were all confirmed at 6-month scanning. PET/CT indicated refractory or persistent disease at 2 and 6 months in the remaining seven patients. Better overall survival was observed for patients with a reduction in the maximum standard uptake value of 49% or higher (both at 2 and 6 months after RIT) when compared with those with a decrease of less than 49% (P < .05).
  
  
  CONCLUSIONS
  Early assessment of response to RIT by using PET/CT might be useful in the identification of patients needing additional therapeutic strategies.
authors.affiliation: Istituto di Ricerca e Cura a Carattere Scientifico, Università Federico II, Via Pansini 5, 80131 Naples, Italy. giosto24@hotmail.com
authors.forename: Giovanni
authors.initials: G
authors.lastname: Storto
authors.forename: Amalia
authors.initials: A
authors.lastname: De Renzo
authors.forename: Teresa
authors.initials: T
authors.lastname: Pellegrino
authors.forename: Fabiana
authors.initials: F
authors.lastname: Perna
authors.forename: Teresa
authors.initials: T
authors.lastname: De Falco
authors.forename: Paola
authors.initials: P
authors.lastname: Erra
authors.forename: Anna
authors.initials: A
authors.lastname: Nardelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Speranza
authors.forename: Michele
authors.initials: M
authors.lastname: Klain
authors.forename: Bruno
authors.initials: B
authors.lastname: Rotoli
authors.forename: Leonardo
authors.initials: L
authors.lastname: Pace
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D016393:Lymphoma, B-Cell / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods; D011446:Prospective Studies; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D016499:Radioimmunotherapy / Q000379:methods*; D019275:Radiopharmaceuticals; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D015021:Yttrium Radioisotopes
chemical_list: D000911:Antibodies, Monoclonal; D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes; D019788:Fluorodeoxyglucose F18; C422802:ibritumomab tiuxetan