title: Correlation between fluorodeoxyglucose hotspots on pretreatment positron emission tomography/CT and preferential sites of local relapse after chemoradiotherapy for head and neck squamous cell carcinoma.
abstract: The potential benefits of18F-fluoro-2-deoxy-D-glucose-positron emission tomography/CT (FDG-PET/CT) imaging for radiotherapy (RT) treatment planning of head and neck squamous cell carcinoma (HNSCC) are increasingly being recognized. It has been suggested that intratumoral subvolumes with high FDG avidity ("hotspots") are potential targets for selected dose escalation. The purposes of this study were to demonstrate that pre-RT FDG-PET/CT can identify intratumoral sites at increased risk of local relapse after RT and to determine an optimal threshold to delineate smaller RT target volumes that would facilitate RT dose escalation without impaired tolerance.
  
  
  
  Seventy-two consecutive patients with locally advanced HNSCC treated by RT ± chemotherapy were included in this study. All patients underwent FDG-PET/CT at initial staging (PETA) and during systematic follow-up (PETR). FDG-PET/CT was coregistered on the initial CT scan with a rigid method. Various subvolumes (AX; × = 30%, 40%, 50%, 60%, 70%, 80%, and 90% standardized uptake value maximum [SUVmax] thresholds) within the primary tumor and in the subsequent local relapse (RX; × = 40% and 70% SUVmax thresholds) were compared together (Dice, Jaccard, overlap fraction, common volume/baseline volume, and common volume/recurrent volume).
  
  
  
  Nineteen patients (26%) had local relapses. Using a 40% SUVmax threshold, the initial metabolic tumor volume was significantly higher in patients with local relapses than in controlled patients (10.4 ± 8.6 vs 5.1 ± 4.9 cc; p = .002) as well as total lesion glycolysis (117.9 ± 88.6 vs 60.6 ± 80.4; p = .013). For both methods, the overlap index among A30, A40, and A50subvolumes on PETAand the whole metabolic volume of recurrence R40and R70on PETRshowed a moderate agreement (0.52 to 0.43).
  
  
  
  Our study does not find high overlap index values between the initial tumor and recurrence subvolumes, probably because of a suboptimal coregistration. Our results also confirm that metabolic tumor volume and total lesion glycolysis are independently correlated with recurrence-free survival in patients with HNSCC. Further larger prospective studies with FDG-PET/CT performed in the same RT position and with a validated elastic registration method are needed. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1155-1165, 2017.
authors.affiliation: Department of Nuclear Medicine, Brest University Hospital, Brest, France.
authors.forename: Anne
authors.identifier: 0000-0002-8099-3318
authors.initials: A
authors.lastname: Chaput
authors.affiliation: Department of Nuclear Medicine, Bichat University Hospital, Inserm 1148, DHU FIRE, Assistance Publique - Hôpitaux de Paris, Paris, France.|Department of Nuclear Medicine and Radiology, Henri Becquerel Center, QuantIF (LITIS EA 4108 - FR CNRS 3638), Rouen University Hospital, Rouen, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Calais
authors.affiliation: Department of Nuclear Medicine, Brest University Hospital, Brest, France.|European University of Brittany, EA3878 GETBO, IFR 148, Brest, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Robin
authors.affiliation: Department of Nuclear Medicine and Radiology, Henri Becquerel Center, QuantIF (LITIS EA 4108 - FR CNRS 3638), Rouen University Hospital, Rouen, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Thureau
authors.affiliation: Department of Nuclear Medicine, Brest University Hospital, Brest, France.
authors.forename: David
authors.initials: D
authors.lastname: Bourhis
authors.affiliation: Department of Nuclear Medicine and Radiology, Henri Becquerel Center, QuantIF (LITIS EA 4108 - FR CNRS 3638), Rouen University Hospital, Rouen, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Modzelewski
authors.affiliation: Department of Radiotherapy, Brest University Hospital, Brest, France.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Schick
authors.affiliation: Department of Nuclear Medicine and Radiology, Henri Becquerel Center, QuantIF (LITIS EA 4108 - FR CNRS 3638), Rouen University Hospital, Rouen, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Vera
authors.affiliation: Department of Nuclear Medicine, Brest University Hospital, Brest, France.|European University of Brittany, EA3878 GETBO, IFR 148, Brest, France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Salaün
authors.affiliation: Department of Nuclear Medicine, Brest University Hospital, Brest, France.|European University of Brittany, EA3878 GETBO, IFR 148, Brest, France.
authors.forename: Ronan
authors.initials: R
authors.lastname: Abgral
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D059248:Chemoradiotherapy / Q000379:methods; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D000077195:Squamous Cell Carcinoma of Head and Neck; D016019:Survival Analysis; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: 18F-fluoro-2-deoxy-D-glucose (FDG) hotspots; 18F-fluoro-2-deoxy-D-glucose-positron emission tomography/CT (FDG-PET/CT); head and neck cancer; local relapse; radiotherapy target volume