Prospective randomized double-blind pilot study of site-specific consensus atlas implementation for rectal cancer target volume delineation in the cooperative group setting

Clifton D. Fuller, Jasper Nijkamp, Joop C. Duppen, Coen R.N. Rasch, Charles R. Thomas, Samuel J. Wang, Paul Okunieff, William E. Jones, Daniel Baseman, Shilpen Patel, Carlo G.N. Demandante, Anna M. Harris, Benjamin D. Smith, Alan W. Katz, Camille McGann, Jennifer L. Harper, Daniel T. Chang, Stephen Smalley, David T. Marshall, Karyn A. GoodmanNiko Papanikolaou, Lisa A. Kachnic

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

Purpose: Variations in target volume delineation represent a significant hurdle in clinical trials involving conformal radiotherapy. We sought to determine the effect of a consensus guideline-based visual atlas on contouring the target volumes. Methods and Materials: A representative case was contoured (Scan 1) by 14 physician observers and a reference expert with and without target volume delineation instructions derived from a proposed rectal cancer clinical trial involving conformal radiotherapy. The gross tumor volume (GTV), and two clinical target volumes (CTVA, including the internal iliac, presacral, and perirectal nodes, and CTVB, which included the external iliac nodes) were contoured. The observers were randomly assigned to receipt (Group A) or nonreceipt (Group B) of a consensus guideline and atlas for anorectal cancers and then instructed to recontour the same case/images (Scan 2). Observer variation was analyzed volumetrically using the conformation number (CN, where CN = 1 equals total agreement). Results: Of 14 evaluable contour sets (1 expert and 7 Group A and 6 Group B observers), greater agreement was found for the GTV (mean CN, 0.75) than for the CTVs (mean CN, 0.46-0.65). Atlas exposure for Group A led to significantly increased interobserver agreement for CTVA (mean initial CN, 0.68, after atlas use, 0.76; p = .03) and increased agreement with the expert reference (initial mean CN, 0.58; after atlas use, 0.69; p = .02). For the GTV and CTVB, neither the interobserver nor the expert agreement was altered after atlas exposure. Conclusion: Consensus guideline atlas implementation resulted in a detectable difference in interobserver agreement and a greater approximation of expert volumes for the CTVA but not for the GTV or CTVB in the specified case. Visual atlas inclusion should be considered as a feature in future clinical trials incorporating conformal RT.

Original languageEnglish (US)
Pages (from-to)481-489
Number of pages9
JournalInternational Journal of Radiation Oncology Biology Physics
Volume79
Issue number2
DOIs
StatePublished - Feb 1 2011

Keywords

  • Atlas
  • Conformal radiotherapy
  • Consensus guideline
  • Cooperative group
  • Target volume delineation

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

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