title: Are Radiation Therapy Oncology Group Para-aortic Contouring Guidelines for Pancreatic Neoplasm applicable to other malignancies--assessment of nodal distribution in gynecological malignancies.
abstract: OBJECTIVE
  Intensity modulated radiation therapy is used to reduce dose to adjacent critical structures while maintaining adequate target coverage, but it requires precise target localization. We report the 3-dimensional distribution of para-aortic (PA) lymph nodes (LN) in pelvic malignancies. We propose a guideline to accurately define the PA LN by anatomic landmarks and compare our data with published guidelines for pancreatic cancer.
  
  
  METHODS
  A retrospective analysis was performed on 46 patients with pelvic malignancies and positive PA LNs. Positive LNs were defined based on size and morphology or fluorodeoxyglucose avidity. All PA LNs were characterized into 3 groups based on location: left PA (between aorta and left psoas muscle), aortocaval (between aorta and inferior vena cava), and right paracaval (between inferior vena cava and right psoas muscle). Patients with retrocrural LNs were also analyzed.
  
  
  RESULTS
  One hundred thirty-three positive PA LNs were evaluated. The majority of the PA LNs were in the left PA (59%) and aortocaval (35) regions, and only 8% were in the right paracaval region. All patients with positive right paracaval LNs also had involved left PA LNs, with only 1 exception. The highest PA LN involvement was at the level of the renal vessels and was seen in 28% of patients. Of these patients with disease extending to renal vessels, 38% had retrocrural LN involvement.
  
  
  CONCLUSIONS
  The nodal contouring for the PA region should not be defined by a fixed circumferential margin around the vessels. The left PA and aortocaval spaces should be covered adequately because these are common locations of PA LNs. For microscopic disease superiorly, contouring should extend up to renal vessels rather than a fixed bony landmark. For patients who have nodal involvement at renal vessels, one can consider including retrocrural LNs. Radiation Therapy Oncology Group Para-aortic Contouring Guidelines for Pancreatic Neoplasm are not applicable to gynecological malignancies.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, USA.
authors.forename: Peyman
authors.initials: P
authors.lastname: Kabolizadeh
authors.forename: Suyash
authors.initials: S
authors.lastname: Fulay
authors.forename: Sushil
authors.initials: S
authors.lastname: Beriwal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging*; D001011:Aorta / Q000000981:diagnostic imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D005833:Genital Neoplasms, Female / Q000000981:diagnostic imaging*; D019983:Guideline Adherence; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis; D008220:Lymphography / Q000592:standards*; D008875:Middle Aged; D064847:Multimodal Imaging; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D017410:Practice Guidelines as Topic; D016658:Psoas Muscles / Q000000981:diagnostic imaging; D018787:Radiation Oncology / Q000592:standards; D019275:Radiopharmaceuticals; D050397:Radiotherapy, Intensity-Modulated; D012077:Renal Artery / Q000000981:diagnostic imaging; D012082:Renal Veins / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18