title: Diagnostic performance of response assessment FDG-PET/CT in patients with head and neck squamous cell carcinoma treated with high-precision definitive (chemo)radiation.
abstract: OBJECTIVE
  To prospectively assess diagnostic performance of response assessment fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in patients with HNSCC treated with high-precision definitive (chemo)radiation.
  
  
  METHODS
  Fifty-seven patients treated on a prospective clinical trial having post-treatment response assessment FDG-PET/CT scans were included. Clinico-pathologic findings and follow-up information was considered as reference standard.
  
  
  RESULTS
  First response assessment FDG-PET/CT was done at a median of 9 weeks (inter-quartile range 8-10 weeks) from completion of treatment. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of first response assessment FDG-PET/CT for identifying residual disease at primary site was 50%, 91.8%, 50%, 91.8%, and 86%. The corresponding figures for the neck were 62.5%, 98%, 83.3%, 94.1%, and 93%. With a median follow-up of 26 months (range 7-45 months), the 3-year loco-regional control (83.9% vs 58.3%, p=0.001) and overall survival (68.8% vs 58.3%, p=0.063) was significantly better in patients with negative response assessment scans.
  
  
  CONCLUSIONS
  The overall diagnostic accuracy of response assessment FDG-PET/CT is good, but its sensitivity and PPV is somewhat low, particularly for primary site. A negative response assessment FDG-PET/CT scan is highly suggestive of absence of viable disease that could be used to guide decision-making.
authors.affiliation: Department of Radiation Oncology, ACTREC/TMH, Mumbai, India. tejpalgupta@rediffmail.com
authors.forename: Tejpal
authors.initials: T
authors.lastname: Gupta
authors.forename: Sandeep
authors.initials: S
authors.lastname: Jain
authors.forename: Jai Prakash
authors.initials: JP
authors.lastname: Agarwal
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Rangarajan
authors.forename: Nilendu
authors.initials: N
authors.lastname: Purandare
authors.forename: Sarbani
authors.initials: S
authors.lastname: Ghosh-Laskar
authors.forename: Ketayun A
authors.initials: KA
authors.lastname: Dinshaw
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000532:radiotherapy / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000175:diagnosis / Q000532:radiotherapy / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18