title: Nasopharyngeal cancers: which method should be used to measure these irregularly shaped tumors on cross-sectional imaging?
abstract: OBJECTIVE
  To determine whether the standard techniques of measuring tumor size and change in size after treatment could be applied to the measurement of nasopharyngeal cancers, which are often irregular in shape.
  
  
  METHODS
  The standard measurements of bidimensional (BDM) (World Health Organization criteria) and unidimensional (UDM) (Response Evaluation Criteria in Solid Tumors [RECIST] criteria), together with the maximum depth of the tumor perpendicular to the pharyngeal wall (DM), were acquired from axial magnetic resonance images of primary nasopharyngeal carcinoma in 44 patients at diagnosis and in 29 of these patients after treatment. Tumor volume measurements (VM), acquired from the summation of areas from the axial magnetic resonance images, were used as the reference standard.
  
  
  RESULTS
  There was a significant association between VM and BDM with respect to tumor size at diagnosis (p = 0.002), absolute change in tumor size after treatment (p < 0.001), and percentage change in tumor size after treatment (p = 0.044), but not between VM and UDM. There was also a significant association between VM and DM with respect to percentage change in tumor size after treatment (p = <0.0001) but not absolute change (p = 0.222).
  
  
  CONCLUSIONS
  When using simple measurements to assess irregularly shaped nasopharyngeal cancers, the BDM should be used to measure size at diagnosis and the BDM and percentage change in size with treatment. Unidimensional measurement does not reflect size or change in size, and therefore the RECIST criteria may not be applicable to all tumor shapes. The use of DM requires further evaluation.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR., China. King2015@cuhk.edu.hk
authors.forename: Ann D
authors.initials: AD
authors.lastname: King
authors.forename: Benny
authors.initials: B
authors.lastname: Zee
authors.forename: Edmund H Y
authors.initials: EH
authors.lastname: Yuen
authors.forename: Sing-Fai
authors.initials: SF
authors.lastname: Leung
authors.forename: David K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: Brigette B
authors.initials: BB
authors.lastname: Ma
authors.forename: Jeffrey K T
authors.initials: JK
authors.lastname: Wong
authors.forename: Michael K M
authors.initials: MK
authors.lastname: Kam
authors.forename: Anil T
authors.initials: AT
authors.lastname: Ahuja
authors.forename: Anthony T C
authors.initials: AT
authors.lastname: Chan
mesh_terms: D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D009367:Neoplasm Staging; D012015:Reference Standards; D012189:Retrospective Studies; D047368:Tumor Burden