title: Early lesion-specific (18)F-FDG PET response to chemotherapy predicts time to lesion progression in locally advanced non-small cell lung cancer.
abstract: OBJECTIVE
  We hypothesize that the lesion-to-lesion variability in FDG-PET response after one cycle of chemotherapy for NSCLC in an individual patient may inform radiation dose redistribution. To test this hypothesis, we investigate if time to lesion-progression in patients with multiple lesions is dependent on lesion-specific response to chemotherapy.
  
  
  METHODS
  We analyzed 81 patients with 184 lesions referred to curative chemo-radiotherapy for NSCLC 2010-2012. (18)F-FDG PET scans were performed at diagnosis and after one series of chemotherapy. Response of each lesion was assessed as the change in FDG peak standardized uptake value. Variance of lesion response was compared within and between patients. Time to progression for each lesion was analyzed using the Kaplan-Meier method and the Cox proportional hazards model.
  
  
  RESULTS
  Within-patient variability in lesion responses was of the same magnitude as the between-patient variability. Lesion-specific time to progression was longer in lesions with a better response (log-rank p=0.038). Nodal lesions had a much lower risk of progression than T-site lesions (HR=0.09, p<0.0001).
  
  
  CONCLUSIONS
  Recording an overall patient response involves a loss of biological information on heterogeneity between lesions. Poor lesion-specific response after one cycle chemotherapy may identify lesions that would benefit from an individualized radiotherapy strategy.
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, Denmark. Electronic address: lotte.nygaard@regionh.dk.
authors.forename: Lotte
authors.initials: L
authors.lastname: Nygård
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Vogelius
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Fischer
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Klausen
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Seppo W
authors.initials: SW
authors.lastname: Langer
authors.affiliation: Department of Clinical Physiology & Nuclear Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
authors.forename: Markus N
authors.initials: MN
authors.lastname: Lonsdale
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, Denmark.
authors.forename: Gitte F
authors.initials: GF
authors.lastname: Persson
authors.affiliation: Division of Biostatistics and Bioinformatics, University of Maryland Greenebaum Cancer Center and Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, USA.
authors.forename: Søren M
authors.initials: SM
authors.lastname: Bentzen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000628:therapy*; D059248:Chemoradiotherapy / Q000379:methods*; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D016016:Proportional Hazards Models; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Early response; FDG PET; Lung cancer