title: Value of 18F-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography in non-small-cell lung cancer for prediction of pathologic response and times to relapse after neoadjuvant chemoradiotherapy.
abstract: OBJECTIVE
  To determine the value of combined positron emission tomography/computed tomography (PET/CT) during induction chemotherapy (CTx) followed by chemoradiotherapy (CTx/RTx) for non-small-cell lung cancer to predict histopathologic response in primary tumor and mediastinum and prognosis of the patient.
  
  
  METHODS
  Fifty consecutive patients with locally advanced non-small-cell lung cancer received induction therapy and, if considered resectable, proceeded to surgery (37 of 50 patients). Patients had at least two repeated 18F-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT scans either before treatment (t0) or after induction CTx (t1) or CTx/RTx (t2). Variables from the PET/CT studies [e.g., lesion volume and corrected maximum standardized glucose uptake values (SUV(max,corr))] were correlated with histopathologic response (graded as 3, 2b, or 2a: 0%, >0-10%, or >10% residual tumor cells) and times to failure.
  
  
  RESULTS
  Primary tumors showed a percentage decrease in SUV(max,corr) during induction significantly larger in grade 2b/3 than in grade 2a responding tumors (67% versus 34% at t(1), 73% versus 49% at t(2); both P < 0.005). SUV(max,corr) at t(2) was significantly correlated with histopathologic response in tumors smaller than the median volume (7.5 cm(3); r = -0.54, P = 0.02). In the mediastinal lymph nodes, SUV(max,corr) values at t2 predicted an ypN0 status with a sensitivity and specificity of 73% and 89%, respectively (SUV(max,corr) threshold of 4.1, r = -0.54, P = 0.0005). Freedom from extracerebral relapse was significantly better in grade 2b/3 patients (86% at 16 months versus 20% in 2a responders; P = 0.003) and in patients with a greater percentage decrease in SUV(max,corr) in the primary tumor at t2 in relation to t0 than in patients with lesser response (83% at 16 months versus 43%; P = 0.03 for cutoff points between 0.45 and 0.55).
  
  
  CONCLUSIONS
  SUV(max,corr) values from two serial PET/CT scans, before and after three chemotherapy cycles or later, allow prediction of histopathologic response in the primary tumor and mediastinal lymph nodes and have prognostic value.
authors.affiliation: Department of Radiotherapy, University of Duisburg-Essen Medical School, Essen. Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Pöttgen
authors.forename: Sabine
authors.initials: S
authors.lastname: Levegrün
authors.forename: Dirk
authors.initials: D
authors.lastname: Theegarten
authors.forename: Simone
authors.initials: S
authors.lastname: Marnitz
authors.forename: Sara
authors.initials: S
authors.lastname: Grehl
authors.forename: Roman
authors.initials: R
authors.lastname: Pink
authors.forename: Wilfried
authors.initials: W
authors.lastname: Eberhardt
authors.forename: Georgios
authors.initials: G
authors.lastname: Stamatis
authors.forename: Thomas
authors.initials: T
authors.lastname: Gauler
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.forename: Andreas
authors.initials: A
authors.lastname: Bockisch
authors.forename: Martin
authors.initials: M
authors.lastname: Stuschke
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18