International consensus guidelines on Clinical Target Volume delineation in rectal cancer

Radiother Oncol. 2016 Aug;120(2):195-201. doi: 10.1016/j.radonc.2016.07.017. Epub 2016 Aug 12.


Introduction: The delineation of Clinical Target Volume (CTV) is a critical step in radiotherapy. Several guidelines suggest different subvolumes and anatomical boundaries in rectal cancer (RC), potentially leading to a misunderstanding in the CTV definition. International consensus guidelines (CG) are needed to improve uniformity in RC CTV delineation.

Material and methods: The 7 radiation oncologist experts defined a roadmap to produce RC CG. Step 1: revision of the published guidelines. Step 2: selection of RC cases with different clinical stages. Step 3: delineation of cases using Falcon following previously published guidelines. Step 4: meeting in person to discuss the initial delineation outcome, followed by a CTV proposal based on revised and if needed, adapted anatomical boundaries. Step 5: peer review of the agreed consensus. Step 6: peer review meeting to validate the final outcome. Step 7: completion of RC delineation atlases.

Results: A new ontology of structure sets was defined and the related table of anatomical boundaries was generated. The major modifications were about the lateral lymph nodes and the ischio-rectal fossa delineation. Seven RC cases were made available online as consultation atlases.

Conclusion: The definition of international CG for RC delineation endorsed by international experts might support a future homogeneous comparison between clinical trial outcomes.

Keywords: Clinical Target Volume delineation; Consensus guidelines; Rectal cancer.

Publication types

  • Consensus Development Conference

MeSH terms

  • Consensus
  • Humans
  • Lymph Nodes / diagnostic imaging
  • Lymph Nodes / pathology
  • Organs at Risk
  • Practice Guidelines as Topic*
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Rectal Neoplasms / diagnostic imaging
  • Rectal Neoplasms / pathology*
  • Rectal Neoplasms / radiotherapy*
  • Tomography, X-Ray Computed