title: Consensus Guidelines and Contouring Atlas for Pelvic Node Delineation in Prostate and Pelvic Node Intensity Modulated Radiation Therapy.
abstract: OBJECTIVE
  The purpose of this study was to establish reproducible guidelines for delineating the clinical target volume (CTV) of the pelvic lymph nodes (LN) by combining the freehand Royal Marsden Hospital (RMH) and Radiation Therapy Oncology Group (RTOG) vascular expansion techniques.
  
  
  METHODS
  Seven patients with prostate cancer underwent standard planning computed tomography scanning. Four different CTVs (RMH, RTOG, modified RTOG, and Prostate and pelvIs Versus prOsTate Alone treatment for Locally advanced prostate cancer [PIVOTAL] trial) were created for each patient, and 6 different bowel expansion margins (BEM) were created to assess bowel avoidance by the CTV. The resulting CTVs were compared visually and by using Jaccard conformity indices. The volume of overlap between bowel and planning target volume (PTV) was measured to aid selection of an appropriate BEM to enable maximal LN yet minimal normal tissue coverage.
  
  
  RESULTS
  In total, 84 nodal contours were evaluated. LN coverage was similar in all groups, with all of the vascular-expansion techniques (RTOG, modified RTOG, and PIVOTAL), resulting in larger CTVs than that of the RMH technique (mean volumes: 287.3 cm(3), 326.7 cm(3), 310.3 cm(3), and 256.7 cm(3), respectively). Mean volumes of bowel within the modified RTOG PTV were 19.5 cm(3) (with 0 mm BEM), 17.4 cm(3) (1-mm BEM), 10.8 cm(3) (2-mm BEM), 6.9 cm(3) (3-mm BEM), 5.0 cm(3) (4-mm BEM), and 1.4 cm(3) (5-mm BEM) in comparison with an overlap of 9.2 cm(3) seen using the RMH technique. Evaluation of conformity between LN-CTVs from each technique revealed similar volumes and coverage.
  
  
  CONCLUSIONS
  Vascular expansion techniques result in larger LN-CTVs than the freehand RMH technique. Because the RMH technique is supported by phase 1 and 2 trial safety data, we proposed modifications to the RTOG technique, including the addition of a 3-mm BEM, which resulted in LN-CTV coverage similar to that of the RMH technique, with reduction in bowel and planning target volume overlap. On the basis of these findings, recommended guidelines including a detailed pelvic LN contouring atlas have been produced and implemented in the PIVOTAL trial.
authors.affiliation: Academic Urology Unit, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, United Kingdom.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Harris
authors.affiliation: Institute of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, Wales, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Staffurth
authors.affiliation: Joint Department of Physics, Institute of Cancer Research, and Royal Marsden NHS Foundation Trust, London, United Kingdom.
authors.forename: Olivia
authors.initials: O
authors.lastname: Naismith
authors.affiliation: Ipswich Hospital NHS Foundation Trust, Ipswich, United Kingdom.
authors.forename: Alikhan
authors.initials: A
authors.lastname: Esmail
authors.affiliation: Joint Department of Physics, Institute of Cancer Research, and Royal Marsden NHS Foundation Trust, London, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Gulliford
authors.affiliation: Academic Urology Unit, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, United Kingdom.
authors.forename: Vincent
authors.initials: V
authors.lastname: Khoo
authors.affiliation: Clinical Trials and Statistics Unit, Institute of Cancer Research, London, United Kingdom.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lewis
authors.affiliation: Clatterbridge Cancer Centre, Liverpool, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Littler
authors.affiliation: Department of Radiotherapy, The Royal Marsden NHS Foundation Trust, London, United Kingdom.
authors.forename: Helen
authors.initials: H
authors.lastname: McNair
authors.affiliation: Beatson West of Scotland Cancer Centre, Scotland, Glasgow, United Kingdom.
authors.forename: Azmat
authors.initials: A
authors.lastname: Sadoyze
authors.affiliation: Ipswich Hospital NHS Foundation Trust, Ipswich, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Scrase
authors.affiliation: Department of Radiology, The Royal Marsden NHS Foundation Trust, London, United Kingdom.
authors.forename: Aslam
authors.initials: A
authors.lastname: Sohaib
authors.affiliation: Clatterbridge Cancer Centre, Liverpool, United Kingdom.
authors.forename: Isabel
authors.initials: I
authors.lastname: Syndikus
authors.affiliation: University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
authors.forename: Anjali
authors.initials: A
authors.lastname: Zarkar
authors.affiliation: Clinical Trials and Statistics Unit, Institute of Cancer Research, London, United Kingdom.
authors.forename: Emma
authors.initials: E
authors.lastname: Hall
authors.affiliation: Academic Urology Unit, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, United Kingdom. Electronic address: David.Dearnaley@icr.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Dearnaley
mesh_terms: D032921:Consensus; D019983:Guideline Adherence; D006801:Humans; D007422:Intestines / Q000000981:diagnostic imaging; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D015182:Lymphatic Irradiation; D008207:Lymphatic Metastasis; D008297:Male; D008488:Medical Illustration; D058958:Organs at Risk / Q000000981:diagnostic imaging; D010388:Pelvis / Q000098:blood supply / Q000000981:diagnostic imaging; D017410:Practice Guidelines as Topic; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging