title: FDG-PET as a potential tool for selecting patients with advanced non-small cell lung cancer who may be spared maintenance therapy after first-line chemotherapy.
abstract: OBJECTIVE
  To investigate whether 18F-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) may be a potential tool to select a subgroup of patients who might be spared maintenance treatment, if the metabolic response after first-line chemotherapy could predict time-to-progression (TTP).
  
  
  METHODS
  A total of 43 patients who underwent baseline FDG-PET scan and did not show disease progression (DP) after 4 cycles of first-line chemotherapy were enrolled and underwent second FDG-PET 3 weeks after completion of the first-line chemotherapy. The primary endpoint was to compare percent decrease in maximum standard uptake value (SUVmax) between early (TTP after second PET examination <8 weeks) and late (TTP ≥8 weeks) DP subgroups. Secondary endpoints were to determine whether fractional decrease in SUVmax could predict TTP and overall survival (OS), both calculated from the date of the second FDG-PET.
  
  
  RESULTS
  Percent decreases in SUVmax in late DP subgroup were greater than those in early DP subgroup (mean reduction, 54.7% ± 27.2% vs. 27.8% ± 46.8%, P = 0.021). Receiver operating characteristic curves identified a 50.0% decrease in SUVmax as the optimal threshold to distinguish these subgroups. Using this value as the cutoff resulted in a positive predictive value of 82.6% and negative predictive value of 60.0% in predicting TTP ≥8 weeks. Patients with SUVmax decrease <50% had significantly longer median TTP (3.0 vs. 1.5 months, P = 0.001) and OS (not reached vs. 14.2 months, P = 0.003).
  
  
  CONCLUSIONS
  Fractional decrease in SUVmax of the main lesion after completion of 4 cycles of chemotherapy may discriminate patients with TTP ≥8 weeks and predict TTP and OS in patients with advanced NSCLC.
authors.affiliation: Departments of Oncology and Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Dok Hyun
authors.initials: DH
authors.lastname: Yoon
authors.forename: Sora
authors.initials: S
authors.lastname: Baek
authors.forename: Chang-Min
authors.initials: CM
authors.lastname: Choi
authors.forename: Dae Ho
authors.initials: DH
authors.lastname: Lee
authors.forename: Cheolwon
authors.initials: C
authors.lastname: Suh
authors.forename: Jin-Sook
authors.initials: JS
authors.lastname: Ryu
authors.forename: Dae Hyuk
authors.initials: DH
authors.lastname: Moon
authors.forename: Jung Shin
authors.initials: JS
authors.lastname: Lee
authors.forename: Sang-We
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D019788:Fluorodeoxyglucose F18