title: Influence of Lymphadenectomy on Survival for Early-Stage Endometrial Cancer.
abstract: OBJECTIVE
  To use a number of methods to control for confounding and selection bias to examine the association between lymphadenectomy and survival in a large cohort of women with endometrial cancer.
  
  
  METHODS
  A retrospective cohort study using the National Cancer Data Base was performed to identify women with endometrioid adenocarcinoma of the endometrium who underwent hysterectomy with or without lymphadenectomy from 1998 to 2011. Traditional regression analysis, propensity score, and an instrumental variable using regional variation in the rate of lymphadenectomy as an instrument were used to examine the association between lymphadenectomy and survival.
  
  
  RESULTS
  A total of 151,089 women treated at 1,336 hospitals were identified; 99,052 (65.6%) patients underwent lymphadenectomy, whereas 52,037 (34.4%) did not. In a multivariable regression model, lymphadenectomy was associated with a 16% reduction in mortality (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.81-0.87). The results were similar after adjustment for adjuvant therapy (HR 0.85, 95% CI 0.82-0.87). The results were largely unchanged and suggested that lymphadenectomy was associated with improved survival after application of a propensity score analysis. In contrast, in the instrumental variable analysis, there was not a statistically significant association between lymphadenectomy and survival (HR 0.75, 95% CI 0.53-1.06), even after adjustment for adjuvant treatment (HR 0.76, 95% CI 0.54-1.06). The results were unchanged for women with T1A and T1B tumors.
  
  
  CONCLUSIONS
  Lymphadenectomy is associated with a modest, if any, effect on survival for women with endometrial cancer.
authors.affiliation: Departments of Obstetrics and Gynecology and Medicine and the Herbert Irving Comprehensive Cancer Center, Columbia University College of Physicians and Surgeons, the Department of Epidemiology, Mailman School of Public Health, Columbia University, New York Presbyterian Hospital, and the Department of Urology, Weill Cornell Medical College, New York, New York.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Wright
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Huang
authors.forename: William M
authors.initials: WM
authors.lastname: Burke
authors.forename: Ana I
authors.initials: AI
authors.lastname: Tergas
authors.forename: June Y
authors.initials: JY
authors.lastname: Hou
authors.forename: Jim C
authors.initials: JC
authors.lastname: Hu
authors.forename: Alfred I
authors.initials: AI
authors.lastname: Neugut
authors.forename: Cande V
authors.initials: CV
authors.lastname: Ananth
authors.forename: Dawn L
authors.initials: DL
authors.lastname: Hershman
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D000369:Aged, 80 and over; D018269:Carcinoma, Endometrioid / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D004522:Educational Status; D016889:Endometrial Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D008197:Lymph Node Excision / Q000401:mortality / Q000706:statistics & numerical data*; D008875:Middle Aged; D009367:Neoplasm Staging; D057216:Propensity Score; D012189:Retrospective Studies; D015983:Selection Bias; D015996:Survival Rate; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data