title: Prognostic role of metabolic parameters of (18)F-FDG PET-CT scan performed during radiation therapy in locally advanced head and neck squamous cell carcinoma.
abstract: OBJECTIVE
  To evaluate the prognostic value of (18)F-FDG PET-CT performed in the third week (iPET) of definitive radiation therapy (RT) in patients with newly diagnosed locally advanced mucosal primary head and neck squamous-cell-carcinoma (MPHNSCC).
  
  
  METHODS
  Seventy-two patients with MPHNSCC treated with radical RT underwent staging PET-CT and iPET. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) of primary tumour (PT) and index node (IN) [defined as lymph node(s) with highest TLG] were analysed, and results were correlated with loco-regional recurrence-free survival (LRFS), disease-free survival (DFS), metastatic failure-free survival(MFFS) and overall survival (OS), using Kaplan-Meier analysis.
  
  
  RESULTS
  Optimal cutoffs (OC) were derived from receiver operating characteristic curves: SUVmax-PT = 4.25 g/mL, MTVPT = 3.3 cm(3), TLGPT = 9.4 g, for PT, and SUVmax-IN = 4.05 g/mL, MTVIN = 1.85 cm(3) and TLGIN = 7.95 g for IN. Low metabolic values in iPET for PT below OC were associated with statistically significant better LRFS and DFS. TLG was the best predictor of outcome with 2-year LRFS of 92.7 % vs. 71.1% [p = 0.005, compared with SUVmax (p = 0.03) and MTV (p = 0.022)], DFS of 85.9% vs. 60.8% [p = 0.005, compared with SUVmax (p = 0.025) and MTV (p = 0.018)], MFFS of 85.9% vs. 83.7% [p = 0.488, compared with SUVmax (p = 0.52) and MTV (p = 0.436)], and OS of 81.1% vs. 75.0% [p = 0.279, compared with SUVmax (p = 0.345) and MTV (p = 0.512)]. There were no significant associations between the percentage reduction of primary tumour metabolic parameters and outcomes. In patients with nodal disease, metabolic parameters below OC (for both PT and IN) were significantly associated with all oncological outcomes, while TLG was again the best predictor: LRFS of 84.0% vs. 55.3% (p = 0.017), DFS of 79.4% vs. 38.6% (p = 0.001), MFFS 86.4% vs. 68.2% (p = 0.034) and OS 80.4% vs. 55.7% (p = 0.045).
  
  
  CONCLUSIONS
  The metabolic parameters of iPET can be useful predictors of patient outcome and potentially have a role in adaptive therapy for MPHNSCC. Among the three parameters, TLG was found to be the best prognostic indicator of oncological outcomes.
authors.affiliation: Cancer Therapy Centre, Liverpool Hospital, Liverpool, NSW, 2170, Australia. myomin176@yahoo.com.au.|University of New South Wales, Sydney, NSW, Australia. myomin176@yahoo.com.au.|Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia. myomin176@yahoo.com.au.
authors.forename: Myo
authors.identifier: http://orcid.org/0000-0002-2130-3508
authors.initials: M
authors.lastname: Min
authors.affiliation: University of New South Wales, Sydney, NSW, Australia.|Department of Nuclear Medicine and Positron Emission Tomography, Liverpool Hospital, Liverpool, NSW, Australia.|University of Western Sydney, Sydney, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Lin
authors.affiliation: Cancer Therapy Centre, Liverpool Hospital, Liverpool, NSW, 2170, Australia.|University of New South Wales, Sydney, NSW, Australia.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Lee
authors.affiliation: University of New South Wales, Sydney, NSW, Australia.|Department of Nuclear Medicine and Positron Emission Tomography, Liverpool Hospital, Liverpool, NSW, Australia.|University of Western Sydney, Sydney, NSW, Australia.
authors.forename: Ivan Ho
authors.initials: IH
authors.lastname: Shon
authors.affiliation: University of New South Wales, Sydney, NSW, Australia.|Department of Nuclear Medicine and Positron Emission Tomography, Liverpool Hospital, Liverpool, NSW, Australia.|University of Western Sydney, Sydney, NSW, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Lin
authors.affiliation: Cancer Therapy Centre, Liverpool Hospital, Liverpool, NSW, 2170, Australia.|University of New South Wales, Sydney, NSW, Australia.|Ingham Institute of Applied Medical Research, Liverpool, NSW, Australia.
authors.forename: Dion
authors.initials: D
authors.lastname: Forstner
authors.affiliation: Cancer Therapy Centre, Liverpool Hospital, Liverpool, NSW, 2170, Australia.
authors.forename: Victoria
authors.initials: V
authors.lastname: Bray
authors.affiliation: Department of Nuclear Medicine and Positron Emission Tomography, Liverpool Hospital, Liverpool, NSW, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Chicco
authors.affiliation: Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW, 2298, Australia.|University of Newcastle, Newcastle, NSW, Australia.
authors.forename: Minh Thi
authors.initials: MT
authors.lastname: Tieu
authors.affiliation: Cancer Therapy Centre, Liverpool Hospital, Liverpool, NSW, 2170, Australia. Allan.Fowler@sswahs.nsw.gov.au.
authors.forename: Allan
authors.initials: A
authors.lastname: Fowler
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Adaptive radiotherapy; FDG PET CT; Head and neck cancer; Metabolic parameters; Prognostic value