title: Diagnostic performance of FDG PET/CT to detect subclinical HNSCC recurrence 6 months after the end of treatment.
abstract: OBJECTIVE
  Posttreatment follow-up for the recurrence of head and neck squamous cell carcinoma (HNSCC) is a diagnostic challenge. Tissue distortion from radiation and surgery can obscure early detection of recurrence by conventional follow-up approaches such as physical examination or conventional imaging. Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT is widely validated for the diagnosis of suspected recurrence. Moreover, we have shown in a previous prospective study the high effectiveness of FDG PET/CT in the assessment of subclinical recurrence 12 months after treatment. The aim of this prospective study was to evaluate the effectiveness of an earlier FDG PET/CT, at 6 months after the end of treatment.
  
  
  METHODS
  All patients treated for histologically proven HNSCC from April 2009 to May 2012 at the University Hospital of Brest who did not show any findings suggestive of recurrence at 6 months of their usual follow-up underwent an FDG PET/CT examination. FDG PET/CT findings were correlated with histopathology or imaging follow-up.
  
  
  RESULTS
  The study included 116 patients. FDG PET/CT examinations were performed within a mean period ± SD of 5.6 ± 1.8 months after treatment. FDG PET/CT examinations exhibited abnormal FDG uptake in 34 patients and found no suspected recurrence in 82 cases. Of these 82 FDG PET/CT considered as negative, only 1 had a recurrence. Among the 34 positive FDG PET/CT, 22 relapsed whereas 12 did not show evidence of recurrence. The sensitivity and specificity of FDG PET/CT in this study for the diagnosis of occult HNSCC recurrence were 96 (22/23) and 87 % (81/93), respectively. The positive predictive value was 65 % (22/34). The negative predictive value was 99 % (81/82). The overall accuracy was 89 % (103/116). Of the 116 patients, FDG PET/CT highlighted 22 (19 %) subclinical recurrences.
  
  
  CONCLUSIONS
  Our study showed the high effectiveness of FDG PET/CT in the assessment of subclinical HNSCC recurrence 6 months after completion of treatment. These results confirmed that FDG PET/CT is more accurate than conventional follow-up physical examination alone in the assessment of recurrence after previous curative treatment for HNSCC, as we previously demonstrated in patients clinically asymptomatic at 12 months.
authors.affiliation: Nuclear Medicine Department, University Hospital of Brest, 2, avenue Foch, 29609, Brest Cedex, France, philippe.robin@chu-brest.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Robin
authors.forename: Ronan
authors.initials: R
authors.lastname: Abgral
authors.forename: Gérald
authors.initials: G
authors.lastname: Valette
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Le Roux
authors.forename: Nathalie
authors.initials: N
authors.lastname: Keromnes
authors.forename: Jean
authors.initials: J
authors.lastname: Rousset
authors.forename: Gaël
authors.initials: G
authors.lastname: Potard
authors.forename: Xavier
authors.initials: X
authors.lastname: Palard
authors.forename: Rémi
authors.initials: R
authors.lastname: Marianowski
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Salaun
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012008:Recurrence; D012680:Sensitivity and Specificity; D000077195:Squamous Cell Carcinoma of Head and Neck; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18