title: Prospective assessment of the prevalence of pelvic, paraaortic and high paraaortic lymph node metastasis in endometrial cancer.
abstract: OBJECTIVE
  To prospectively define the prevalence of lymph node metastasis (LNM) in at risk endometrial cancer (EC).
  
  
  METHODS
  From 2004 to 2008, frozen section based Mayo Criteria prospectively identified patients "not at-risk" of LNM (30% EC population; grade I/II, <50% myometrial invasion and tumor diameter ≤ 2 cm) where lymphadenectomy was not recommended. The remaining 70% EC cohort was considered "at-risk" of LNM; where a systematic pelvic and infrarenal paraaortic lymphadenectomy was recommended. Patients were prospectively followed. The area between renal vein and inferior mesenteric artery (IMA) was labeled as high paraaortic area. For calculating the prevalence of LNM in high paraaortic area, the denominator was the population with known anatomic location of nodal tissue in relation to the IMA.
  
  
  RESULTS
  Of the 742 patients, 514 were at risk; of which 89% underwent recommended lymphadenectomy. A mean (± standard deviation) of 36 (± 14) pelvic and 18 (± 9) paraaortic nodes were harvested. The prevalence of pelvic and paraaortic LNM was 17% and 12%, respectively. In presence of pelvic LNM, 51% had paraaortic LNM. In absence of pelvic LNM, 3% had paraaortic LNM; of which 67% was located exclusively in high paraaortic area. Among patients with paraaortic LNM, 88% had high paraaortic LNM; and 35% had only high paraaortic LNM. The cases of paraaortic LNM with negative pelvic nodes seemed to cluster in moderate to high grade endometrioid EC with ≥ 50% myometrial invasion.
  
  
  CONCLUSIONS
  We present reference data for the prevalence of LNM in at-risk EC patients to guide lymphadenectomy decisions for clinical and research purposes.
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, USA. Electronic address: Kumar.sanjeev@mayo.edu.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, USA.
authors.forename: Karl C
authors.initials: KC
authors.lastname: Podratz
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, USA.
authors.forename: Jamie N
authors.initials: JN
authors.lastname: Bakkum-Gamez
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, USA.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Dowdy
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Weaver
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Michaela E
authors.initials: ME
authors.lastname: McGree
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Cliby
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Keeney
authors.affiliation: Department of Radiation Oncology, University of Toronto, Canada.
authors.forename: Gillian
authors.initials: G
authors.lastname: Thomas
authors.affiliation: Division of Gynecologic Surgery, Mayo Clinic, Rochester, MN, USA. Electronic address: mariani.andrea@mayo.edu.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mariani
mesh_terms: D016889:Endometrial Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D011446:Prospective Studies
keywords: Endometrial cancer; Lymph node metastasis; Lymphadenectomy; Risk factors