title: Is 18F-FDG PET/CT useful for the early prediction of histopathologic response to neoadjuvant erlotinib in patients with non-small cell lung cancer?
abstract: Early prediction of treatment response is of value in avoiding the unnecessary toxicity of ineffective treatment. The objective of this study was to prospectively evaluate the role of integrated (18)F-FDG PET/CT for the early identification of response to neoadjuvant erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor.
  
  
  METHODS
  From October 2006 to March 2009, 23 patients with non-small cell lung cancer eligible for surgical resection were evaluated for this study. Patients received preoperative erlotinib (150 mg) once daily for 3 wk. (18)F-FDG PET/CT was performed before and at 1 wk after the administration of erlotinib. Changes in tumor (18)F-FDG uptake during treatment were measured by standardized uptake values and assessed prospectively according to the criteria of the European Organization for Research and Treatment of Cancer. Patients with a decrease in standardized uptake values of 25% or more after 1 wk were classified as "metabolic responders." The metabolic response was compared with the pathologic response, obtained by histopathologic examination of the resected specimen.
  
  
  RESULTS
  Following the (18)F-FDG PET/CT criteria of the European Organization for Research and Treatment of Cancer, 6 patients (26%) had a partial response within 1 wk, 16 patients (70%) had stable disease, and 1 patient (4%) had progressive disease. The median percentage of necrosis in the early metabolic responder group was 70% (interquartile range, 30%-91%), and the median percentage of necrosis in the nonresponder group was 40% (interquartile range, 20%-50%; P = 0.09). The kappa-agreement between the metabolic and pathologic responders was 0.55 (P = 0.008).
  
  
  CONCLUSIONS
  The results of this study suggest that early during the course of epidermal growth factor receptor tyrosine kinase inhibitor therapy, (18)F-FDG PET/CT can predict response to erlotinib treatment in patients with non-small cell lung cancer.
authors: Department of Nuclear Medicine, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors: Tjeerd S
authors: TS
authors: Aukema
authors: Ingrid
authors: I
authors: Kappers
authors: Renato A Valdés
authors: RA
authors: Olmos
authors: Henk E
authors: HE
authors: Codrington
authors: Harm
authors: H
authors: van Tinteren
authors: Renée
authors: R
authors: van Pel
authors: Houke M
authors: HM
authors: Klomp
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D000069347:Erlotinib Hydrochloride; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011799:Quinazolines / Q000627:therapeutic use*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D011799:Quinazolines; D019788:Fluorodeoxyglucose F18; D000069347:Erlotinib Hydrochloride