title: Comparison of conventional and 3-dimensional computed tomography against histopathologic examination in determining pancreatic adenocarcinoma tumor size: implications for radiation therapy planning.
abstract: OBJECTIVE
  This study seeks to: (a) quantify radiologic-pathologic discrepancy for pancreatic adenocarcinoma by comparing tumor size on conventional computed tomography (C-CT) and 3-dimensional CT (3D-CT) to corresponding pathologic specimens; and (b) to identify clinico-pathologic characteristics predictive of radiologic-pathologic discrepancy to assist radiotherapy planning.
  
  
  METHODS
  Sixty-three patients with pancreatic adenocarcinoma and preoperative C-CT and volume-rendered 3D-CT imaging within 6 weeks of resection were identified. Maximum tumor diameter (MTD) was measured on pathology, C-CT, and 3D-CT and compared for each patient as well as among different clinico-pathologic subgroups.
  
  
  RESULTS
  There was a trend toward C-CT underestimation of MTD compared to final pathology (p=0.08), but no significant difference between 3D-CT MTD and pathology (p=0.54). Pathologic tumor size was significantly underestimated by C-CT in patients with larger pathologic tumor size (>3.0 cm, p=0.0001), smaller tumor size on C-CT (<3.0 cm, p=0.003), higher CA19-9 (>90 U/mL, p=0.008), and location in the pancreatic head (p=0.015). A model for predicting pathologic MTD using C-CT MTD and CA19-9 level was generated.
  
  
  CONCLUSIONS
  3D-CT may allow for more accurate contouring of pancreatic tumors than C-CT. Patients with the above clinico-pathologic characteristics may require expanded margins relative to tumor size estimates on C-CT during radiotherapy planning.
authors.affiliation: Department of Radiation Oncology & Molecular Radiation Sciences, Sol Goldman Pancreatic Cancer Research Center, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
authors.forename: Haoming
authors.initials: H
authors.lastname: Qiu
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Wild
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Elliot K
authors.initials: EK
authors.lastname: Fishman
authors.forename: Ralph H
authors.initials: RH
authors.lastname: Hruban
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Laheru
authors.forename: Rachit
authors.initials: R
authors.lastname: Kumar
authors.forename: Amy
authors.initials: A
authors.lastname: Hacker-Prietz
authors.forename: Richard
authors.initials: R
authors.lastname: Tuli
authors.forename: Erik
authors.initials: E
authors.lastname: Tryggestad
authors.forename: Richard D
authors.initials: RD
authors.lastname: Schulick
authors.forename: John L
authors.initials: JL
authors.lastname: Cameron
authors.forename: Barish H
authors.initials: BH
authors.lastname: Edil
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pawlik
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Wolfgang
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Herman
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D010180:Pancreatectomy / Q000379:methods; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D020266:Radiotherapy, Conformal / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome