Definition of the Rectum: An International, Expert-based Delphi Consensus

Nigel D'Souza*, Michael P. M. de Neree Tot Babberich, Andre d'Hoore, Emmanuel Tiret, Evaghelos Xynos, Regina G. H. Beets-Tan, Iris D. Nagtegaal, Lennart Blomqvist, Torbjorn Holm, Bengt Glimelius, Antonio Lacy, Andres Cervantes, Robert Glynne-Jones, Nicholas P. West, Rodrigo O. Perez, Claudio Quadros, Kil Yeon Lee, Thandinkosi E. Madiba, Steven D. Wexner, Julio Garcia-AguilarDushyant Sahani, Brendan Moran, Paris Tekkis, Harm J. Rutten, Pieter J. Tanis, Theo Wiggers, Gina Brown

*Corresponding author for this work

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Background: The wide global variation in the definition of the rectum has led to significant inconsistencies in trial recruitment, clinical management, and outcomes. Surgical technique and use of preoperative treatment for a cancer of the rectum and sigmoid colon are radically different and dependent on the local definitions employed by the clinical team. A consensus definition of the rectum is needed to standardise treatment.

Methods: The consensus was conducted using the Delphi technique with multidisciplinary colorectal experts from October, 2017 to April, 2018.

Results: Eleven different definitions for the rectum were used by participants in the consensus. Magnetic resonance imaging (MRI) was the most frequent modality used to define the rectum (67%), and the preferred modality for 72% of participants. The most agreed consensus landmark (56%) was "the sigmoid take-off,'' an anatomic, image-based definition of the junction of the mesorectum and mesocolon. In the second round, 81% of participants agreed that the sigmoid take-off as seen on computed tomography or MRI achieved consensus, and that it could be implemented in their institution. Also, 87% were satisfied with the sigmoid take-off as the consensus landmark.

Conclusion: An international consensus definition for the rectumis the point of the sigmoid take-off as visualized on imaging. The sigmoid take-off can be identified as the mesocolon elongates as the ventral and horizontal course of the sigmoid on axial and sagittal views respectively on cross-sectional imaging. Routine application of this landmark during multidisciplinary team discussion for all patients will enable greater consistency in tumour localisation.

Original languageEnglish
Pages (from-to)955-959
Number of pages5
JournalAnnals of Surgery
Issue number6
Publication statusPublished - Dec 2019


  • anatomy
  • MRI
  • rectum
  • sigmoid

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