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Consequences of anorectal cancer atlas implementation in the cooperative group setting: radiobiologic analysis of a prospective randomized in silico target delineation study. Radiother Oncol 2014 Sep;112(3):418-24



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Pubmed Central ID




Scopus ID

2-s2.0-84911006491   10 Citations


PURPOSE: The aim of this study is to ascertain the subsequent radiobiological impact of using a consensus guideline target volume delineation atlas.

MATERIALS AND METHODS: Using a representative case and target volume delineation instructions derived from a proposed IMRT rectal cancer clinical trial, gross tumor volume (GTV) and clinical/planning target volumes (CTV/PTV) were contoured by 13 physician observers (Phase 1). The observers were then randomly assigned to follow (atlas) or not-follow (control) a consensus guideline/atlas for anorectal cancers, and instructed to re-contour the same case (Phase 2).

RESULTS: The atlas group was found to have increased tumor control probability (TCP) after the atlas intervention for both the CTV (p<0.0001) and PTV1 (p=0.0011) with decreasing normal tissue complication probability (NTCP) for small intestine, while the control group did not. Additionally, the atlas group had reduced variance in TCP for all target volumes and reduced variance in NTCP for the bowel. In Phase 2, the atlas group had increased TCP relative to the control for CTV (p=0.03).

CONCLUSIONS: Visual atlas and consensus treatment guideline usage in the development of rectal cancer IMRT treatment plans reduced the inter-observer radiobiological variation, with clinically relevant TCP alteration for CTV and PTV volumes.

Author List

Mavroidis P, Giantsoudis D, Awan MJ, Nijkamp J, Rasch CR, Duppen JC, Thomas CR Jr, Okunieff P, Jones WE 3rd, Kachnic LA, Papanikolaou N, Fuller CD, Southwest Oncology Group Radiation Oncology Committee


Musaddiq J. Awan MD Assistant Professor in the Radiation Oncology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Computer Simulation
Cooperative Behavior
Observer Variation
Practice Guidelines as Topic
Prospective Studies
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Intensity-Modulated
Rectal Neoplasms
Tumor Burden