title: Predictive value of pre-therapy (18)F-FDG PET/CT for the outcome of (18)F-FDG PET-guided radiotherapy in patients with head and neck cancer.
abstract: OBJECTIVE
  The aim of this study was to evaluate the predictive role of pre-therapy fluorodeoxyglucose (FDG) uptake parameters of primary tumour in head and neck cancer (HNC) patients undergoing intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) on FDG-positive volume-positron emission tomography (PET) gross tumour volume (PET-GTV).
  
  
  METHODS
  This retrospective study included 19 patients (15 men and 4 women, mean age 59.2 years, range 23-81 years) diagnosed with HNC between 2005 and 2011. Of 19 patients, 15 (79 %) had stage III-IV. All patients underwent FDG PET/CT before treatment. Metabolic indexes of primary tumour, including metabolic tumour volume (MTV), maximum and mean standardized uptake value (SUVmax, SUVmean) and total lesion glycolysis (TLG) were considered. Partial volume effect correction (PVC) was performed for SUVmean and TLG estimation. Correlations between PET/CT parameters and 2-year disease-free survival (DFS), local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) were assessed. Median patient follow-up was 19.2 months (range 4-24 months).
  
  
  RESULTS
  MTV, TLG and PVC-TLG predicting patients' outcome with respect to all the considered local and distant disease control endpoints (LRFS, DMFS and DFS) were 32.4 cc, 469.8 g and 547.3 g, respectively. SUVmean and PVC-SUVmean cut-off values predictive of LRFS and DFS were 10.8 and 13.3, respectively. PVC was able to compensate errors up to 25 % in the primary HNC tumour uptake. Moreover, PVC enhanced the statistical significance of the results.
  
  
  CONCLUSIONS
  FDG PET/CT uptake parameters are predictors of patients' outcome and can potentially identify patients with higher risk of treatment failure that could benefit from more aggressive approaches. Application of PVC is recommended for accurate measurement of PET parameters.
authors.affiliation: Nuclear Medicine, Scientific Institute San Raffaele, via Olgettina, 60, 20132, Milan, Italy, picchio.maria@hsr.it.
authors.forename: M
authors.initials: M
authors.lastname: Picchio
authors.forename: M
authors.initials: M
authors.lastname: Kirienko
authors.forename: P
authors.initials: P
authors.lastname: Mapelli
authors.forename: I
authors.initials: I
authors.lastname: Dell'Oca
authors.forename: E
authors.initials: E
authors.lastname: Villa
authors.forename: F
authors.initials: F
authors.lastname: Gallivanone
authors.forename: L
authors.initials: L
authors.lastname: Gianolli
authors.forename: C
authors.initials: C
authors.lastname: Messa
authors.forename: I
authors.initials: I
authors.lastname: Castiglioni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023381:Endpoint Determination; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D061089:Radiotherapy, Image-Guided; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18