title: Prediction of response by FDG PET early during concurrent chemoradiotherapy for locally advanced non-small cell lung cancer.
abstract: OBJECTIVE
  To evaluate the predictive value of the early response of (18)F-flurodeoxyglucose positron emission tomography (FDG PET) during concurrent chemoradiotherapy (CCRT) for locally advanced non-small cell lung cancer (NSCLC).
  
  
  METHODS
  FDG PET was performed before and during CCRT for 13 NSCLC patients. Maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured and the changes were calculated. These early metabolic changes were compared with the standard tumor response by computed tomograms (CT) one month after CCRT.
  
  
  RESULTS
  One month after the completion of CCRT, 9 patients had partial response (PR) of tumor and 4 patients had stable disease. The percent changes of SUVmax (%ΔSUVmax) were larger in responder group than in non-responder group (55.7% ± 15.6% vs. 23.1% ± 19.0%, p = 0.01). The percent changes of SUVmean (%ΔSUVmean) were also larger in responder group than in non-responder group (54.4% ± 15.9% vs. 22.3% ± 23.0%, p = 0.01). The percent changes of MTV (%ΔMTV) or TLG (%ΔTLG) had no correlation with the tumor response after treatment. All the 7 patients (100%) with %ΔSUVmax ≥ 50% had PR, but only 2 out of 6 patients (33%) with %ΔSUVmax < 50% had PR after CCRT (p = 0.009). Likewise, all the 6 patients (100%) with %ΔSUVmean ≥ 50% had PR, but only 3 out of 7 patients (43%) with %ΔSUVmean < 50% had PR after CCRT (p = 0.026).
  
  
  CONCLUSIONS
  The degree of metabolic changes measured by PET-CT during CCRT was predictive for NSCLC tumor response after CCRT.
authors.affiliation: Department of Radiation Oncology, SMG-Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Suzy
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, SMG-Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: So Won
authors.initials: SW
authors.lastname: Oh
authors.affiliation: Department of Internal Medicine, SMG-Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, SMG-Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Ki Hwan
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, SMG-Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Yu Kyeong
authors.initials: YK
authors.lastname: Kim
keywords: Chemoradiotherapy; Lung neoplasms; Positron-emission tomography; RECIST