title: Relationship between non-small cell lung cancer FDG uptake at PET, tumor histology, and Ki-67 proliferation index.
abstract: BACKGROUND
  We compared primary non-small cell lung cancer (NSCLC) F-fluorodeoxyglucose (FDG) uptake at positron emission tomography (PET) to tumor histologic features and Ki-67 proliferation index. This large, prospectively-recruited patient cohort has previously been analyzed based on differences in FDG uptake across stage groups; the current analysis adds further dimensions to this characterization.
  
  
  METHODS
  One hundred seventy-eight patients with potentially-resectable NSCLC were scanned with FDG PET before therapy. A partial volume correction algorithm was used to correct FDG uptake values for their dependence on tumor size. Primary tumor resection specimens, core biopsies, and biopsies of metastatic lymph nodes were used to assess each tumor's NSCLC histologic subtype, degree of differentiation, and Ki-67 proliferation index.
  
  
  RESULTS
  Bronchioalveolar carcinomas were found to have lower FDG uptake at PET and lower Ki-67 scores than any other histologic subtype. Non-bronchioalveolar adenocarcinomas had lower FDG uptake and Ki-67 scores than squamous cell carcinomas or large cell undifferentiated carcinomas. Better differentiated NSCLCs had lower FDG uptake and Ki-67 scores than more poorly differentiated NSCLCs. There was a significant positive correlation between FDG uptake and Ki-67 scores. Partial volume correction increased the strength of this correlation, while also diminishing the strong positive correlation between FDG uptake and tumor size.
  
  
  CONCLUSIONS
  There are significant differences in NSCLC FDG uptake across histologic subtypes and differentiation groups. These differences parallel nearly identical differences in Ki-67 scores, implying that differences in NSCLC tumor cell proliferation may give rise to commensurate differences in tumor glucose metabolism.
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA. vesselle@u.washington.edu
authors.forename: Hubert
authors.initials: H
authors.lastname: Vesselle
authors.forename: Alexander
authors.initials: A
authors.lastname: Salskov
authors.forename: Eric
authors.initials: E
authors.lastname: Turcotte
authors.forename: Linda
authors.initials: L
authors.lastname: Wiens
authors.forename: Rodney
authors.initials: R
authors.lastname: Schmidt
authors.forename: C Diana
authors.initials: CD
authors.lastname: Jordan
authors.forename: Eric
authors.initials: E
authors.lastname: Vallières
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Wood