title: Histopathology of lung adenocarcinoma based on new IASLC/ATS/ERS classification: prognostic stratification with functional and metabolic imaging biomarkers.
abstract: OBJECTIVE
  To correlate the results of histopathologic subtyping and grading of lung adenocarcinoma with maximum standardized uptake values (SUVmax) on positron emission tomography (PET)/computed tomography and apparent diffusion coefficient (ADC) values on diffusion-weighted MRI (DWI).
  
  
  METHODS
  Forty-three patients were included. The SUVmax and mean ADC values of tumors were measured and correlated with the histologic subtypes and grades of lung adenocarcinomas based on the IASLC/ATS/ERS classification scheme. Disease-free survival (DFS) was estimated by using the Kaplan-Meier method, and the log-rank test was used to evaluate differences among three histologic grades or subgroups classified with imaging biomarker study results.
  
  
  RESULTS
  Five (12.5%) tumors belonged to low grade, 30 (70%) to intermediate grade, and 8 (18.5%) to high grade, and patients with low-grade histology had lower risk of recurrence than those with intermediate- or high-grade histology (P = 0.048). A significant difference in SUVmax and mean ADC values was observed among three histologic grades (Ps < 0.001). Regarding DFS, lower metabolic (PET) activity or higher functional (DWI) diffusivity showed longer DFS. When patients (n = 30; 70% of patients) with intermediate histologic grade were subgrouped in consideration of both SUVmax and mean ADC results, combining metabolic and functional criteria helped stratify patients more precisely (P = 0.006).
  
  
  CONCLUSIONS
  SUVmax and mean ADC value correlate well with the histologic grades in lung adenocarcinomas, and combining both imaging biomarker study results leads to more useful stratification of patients into different prognostic subsets than the results of each study.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Ho Yun
authors.initials: HY
authors.lastname: Lee
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Jeong
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Chin A
authors.initials: CA
authors.lastname: Yi
authors.forename: Byung-Tae
authors.initials: BT
authors.lastname: Kim
authors.forename: Hee
authors.initials: H
authors.lastname: Kang
authors.forename: O Jung
authors.initials: OJ
authors.lastname: Kwon
authors.forename: Young Mog
authors.initials: YM
authors.lastname: Shim
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000175:diagnosis* / Q000473:pathology*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D038524:Diffusion Magnetic Resonance Imaging; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor
keywords: diffusion-weighted MR imaging (DWI); histology; lung adenocarcinoma; positron emission tomography (PET); prognosis