title: Redefining stage I endometrial cancer: incorporating histology, a binary grading system, myometrial invasion, and lymph node assessment.
abstract: OBJECTIVE
  We propose a new staging system for stage I endometrial cancer and compare its performance to the 1988 and 2009 International Federation of Gynecology and Obstetrics (FIGO) systems.
  
  
  METHODS
  We analyzed patients with 1988 FIGO stage I endometrial cancer from January 1993 to August 2011. Low-grade carcinoma consisted of endometrioid grade 1 to grade 2 lesions. High-grade carcinoma consisted of endometrioid grade 3 or nonendometrioid carcinomas (serous, clear cell, and carcinosarcoma). The proposed system is as follows:IA. Low-grade carcinoma with less than half myometrial invasionIB. High-grade carcinoma with no myometrial invasionIC. Low-grade carcinoma with half or greater myometrial invasionID. High-grade carcinoma with any myometrial invasion
  
  
  RESULTS
  Data from 1843 patients were analyzed. When patients were restaged with our proposed system, the 5-year overall survival significantly differed (P < 0.001): IA1, 96.7%; IA2, 92.2%; IB1, 92.2%; IB2, 76.4%; IC1, 83.9%; IC2, 78.6%; ID1, 81.1%; and ID2, 68.8%. The bootstrap-corrected concordance probability estimate for the proposed system was 0.627 (95% confidence interval, 0.590-0.664) and was superior to the concordance probability estimate of 0.530 (95% confidence interval, 0.516-0.544) for the 2009 FIGO system.
  
  
  CONCLUSIONS
  By incorporating histological subtype, grade, myometrial invasion, and whether lymph nodes were removed, our proposed system for stage I endometrial cancer has a superior predictive ability over the 2009 FIGO staging system and provides a novel binary grading system (low-grade including endometrioid grade 1-2 lesions; high-grade carcinoma consisting of endometrioid grade 3 carcinomas and nonendometrioid carcinomas).
authors.affiliation: *Gynecology Service, Department of Surgery, †Department of Pathology, and ‡Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY; §Weill Cornell Medical College, New York, NY; ∥Gynecologic Medical Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and ¶Department of Pathology and Molecular Genetics and Research Laboratory, Hospital Universitari Arnau de Vilanova, University of Lleida, IRBLLEIDA, Lleida, Spain.
authors.forename: Joyce N
authors.initials: JN
authors.lastname: Barlin
authors.forename: Robert A
authors.initials: RA
authors.lastname: Soslow
authors.forename: Megan
authors.initials: M
authors.lastname: Lutz
authors.forename: Qin C
authors.initials: QC
authors.lastname: Zhou
authors.forename: Caryn M
authors.initials: CM
authors.lastname: St Clair
authors.forename: Mario M
authors.initials: MM
authors.lastname: Leitao
authors.forename: Alexia
authors.initials: A
authors.lastname: Iasonos
authors.forename: Martee L
authors.initials: ML
authors.lastname: Hensley
authors.forename: Richard R
authors.initials: RR
authors.lastname: Barakat
authors.forename: Xavier
authors.initials: X
authors.lastname: Matias-Guiu
authors.forename: Nadeem R
authors.initials: NR
authors.lastname: Abu-Rustum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018269:Carcinoma, Endometrioid / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*; D016889:Endometrial Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009215:Myometrium / Q000473:pathology; D060787:Neoplasm Grading / Q000379:methods; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging / Q000379:methods*; D016019:Survival Analysis