title: Australasian Gastrointestinal Trials Group (AGITG) contouring atlas and planning guidelines for intensity-modulated radiotherapy in anal cancer.
abstract: OBJECTIVE
  To develop a high-resolution target volume atlas with intensity-modulated radiotherapy (IMRT) planning guidelines for the conformal treatment of anal cancer.
  
  
  METHODS
  A draft contouring atlas and planning guidelines for anal cancer IMRT were prepared at the Australasian Gastrointestinal Trials Group (AGITG) annual meeting in September 2010. An expert panel of radiation oncologists contoured an anal cancer case to generate discussion on recommendations regarding target definition for gross disease, elective nodal volumes, and organs at risk (OARs). Clinical target volume (CTV) and planning target volume (PTV) margins, dose fractionation, and other IMRT-specific issues were also addressed. A steering committee produced the final consensus guidelines.
  
  
  RESULTS
  Detailed contouring and planning guidelines and a high-resolution atlas are provided. Gross tumor and elective target volumes are described and pictorially depicted. All elective regions should be routinely contoured for all disease stages, with the possible exception of the inguinal and high pelvic nodes for select, early-stage T1N0. A 20-mm CTV margin for the primary, 10- to 20-mm CTV margin for involved nodes and a 7-mm CTV margin for the elective pelvic nodal groups are recommended, while respecting anatomical boundaries. A 5- to 10-mm PTV margin is suggested. When using a simultaneous integrated boost technique, a dose of 54 Gy in 30 fractions to gross disease and 45 Gy to elective nodes with chemotherapy is appropriate. Guidelines are provided for OAR delineation.
  
  
  CONCLUSIONS
  These consensus planning guidelines and high-resolution atlas complement the existing Radiation Therapy Oncology Group (RTOG) elective nodal ano-rectal atlas and provide additional anatomic, clinical, and technical instructions to guide radiation oncologists in the planning and delivery of IMRT for anal cancer.
authors.affiliation: Radiation Oncology Victoria, Victoria, Australia. mng@radoncvic.com.au
authors.forename: Michael
authors.initials: M
authors.lastname: Ng
authors.forename: Trevor
authors.initials: T
authors.lastname: Leong
authors.forename: Sarat
authors.initials: S
authors.lastname: Chander
authors.forename: Julie
authors.initials: J
authors.lastname: Chu
authors.forename: Andrew
authors.initials: A
authors.lastname: Kneebone
authors.forename: Susan
authors.initials: S
authors.lastname: Carroll
authors.forename: Kirsty
authors.initials: K
authors.lastname: Wiltshire
authors.forename: Samuel
authors.initials: S
authors.lastname: Ngan
authors.forename: Lisa
authors.initials: L
authors.lastname: Kachnic
mesh_terms: D001005:Anus Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging; D008297:Male; D008488:Medical Illustration; D009367:Neoplasm Staging / Q000379:methods; D058958:Organs at Risk / Q000000981:diagnostic imaging*; D010388:Pelvis / Q000000981:diagnostic imaging; D011859:Radiography; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging; D012737:Sex Factors; D047368:Tumor Burden