title: Morphological analysis of pancreatic adenocarcinoma on multidetector row computed tomography: implications for treatment response evaluation.
abstract: OBJECTIVE
  Response Evaluation Criteria in Solid Tumors (RECIST) guidelines assume spherical shape of tumors. Morphology of pancreatic adenocarcinoma (PAC) on multidetector row computed tomography was investigated to evaluate the applicability of RECIST guidelines.
  
  
  METHODS
  Study population comprised 16 patients with histologically confirmed localized PAC enrolled in a phase II clinical trial of chemoradiation. Pancreatic adenocarcinomas were segmented on baseline and follow-up multidetector row computed tomography with commercially available software. Tumor volumes (mL), RECIST diameter (mm), volume equivalent sphere diameter (VESD, mm), maximum 3-dimensional diameter (M3DD, mm), and elongation value were obtained. RECIST diameter, VESD and M3DD of the tumors at baseline and follow-up were compared to determine differences. Elongation values were analyzed. The significance level was set at P less than 0.05.
  
  
  RESULTS
  Mean volume, RECIST diameter, VESD, M3DD, and elongation for baseline versus follow-up studies were 23.12 mL versus 19.43 mL (P > 0.05), 41.86 mm versus 39.35 mm (P > 0.05), 33.14 mm versus 32.1 mm (P > 0.05), 51.76 mm versus 51.73 mm (P > 0.05), and 0.67 versus 0.76 (P > 0.05), respectively. There was a significant difference at baseline and follow-up between RECIST diameter, VESD, and M3DD (P < 0.05, in all instances).
  
  
  CONCLUSIONS
  Our results suggest that PACs are not spherical in shape. Evaluation of PAC treatment response based on RECIST guidelines may not be accurate.
authors.affiliation: Department of Radiology, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Pedram
authors.initials: P
authors.lastname: Rezai
authors.forename: Mary F
authors.initials: MF
authors.lastname: Mulcahy
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Tochetto
authors.forename: Senta
authors.initials: S
authors.lastname: Berggruen
authors.forename: Vahid
authors.initials: V
authors.lastname: Yaghmai
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000628:therapy; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017322:Clinical Trials, Phase II as Topic; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D017410:Practice Guidelines as Topic / Q000592:standards; D011379:Prognosis; D011878:Radiotherapy; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000592:standards; D016896:Treatment Outcome