title: Does a groin node dissection in vulvar cancer affect groin recurrence and overall survival?: Results from a population-based cohort study.
abstract: BACKGROUND
  To determine, in a population-based cohort of vulvar cancer patients, if groin node dissection (GND) decreases the risk of groin recurrence and increases overall survival.
  
  
  METHODS
  This population-based retrospective cohort study includes all cases of invasive squamous cell carcinoma identified in a provincial cancer registry from 1998 to 2007. Data collection was completed for all clinical and pathologic factors by chart abstraction. Cumulative incidence functions for recurrence were estimated, accounting for death before recurrence as a competing risk. Multivariable Cox regression models examined the associations between GND and groin recurrence, and overall survival.
  
  
  RESULTS
  Clinical and pathologic data were collected for 1109 patients, of which 1038 patients were eligible for GND. 647 patients (62%) had a GND, while 391 patients (38%) did not. Median follow-up was 2.8years. Cumulative incidence plots demonstrate that the risk of death without recurrence was consistently higher than groin recurrence in each year after diagnosis. On multivariate analysis, GND was not significantly associated with decreased groin recurrence (HR 0.91, 95% CI 0.58-1.44, p=0.70). The hazard of death was 15% lower for women who received GND (HR 0.85, 95% CI 0.63-1.16, p=0.32), but this difference was not statistically significant.
  
  
  CONCLUSIONS
  There was no significant difference in groin recurrence or overall survival in those with or without GND in this population-based cohort, raising questions whether a subgroup of patients may not benefit from GND. Patients had a higher probability of dying before groin recurrence could occur. Future trial design should consider death as a competing risk.
authors.affiliation: Division of Gynecologic Oncology, Odette Cancer Centre, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada. Electronic address: lilian.gien@sunnybrook.ca.
authors.forename: Lilian T
authors.initials: LT
authors.lastname: Gien
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Rinku
authors.initials: R
authors.lastname: Sutradhar
authors.affiliation: University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Gillian
authors.initials: G
authors.lastname: Thomas
authors.affiliation: Division of Gynecologic Oncology, Odette Cancer Centre, Toronto, Ontario, Canada; University of Toronto, Toronto, Ontario, Canada.
authors.forename: Allan
authors.initials: A
authors.lastname: Covens
authors.affiliation: Division of Gynecologic Oncology, Juravinski Cancer Centre, Hamilton, Ontario, Canada.
authors.forename: Laurie
authors.initials: L
authors.lastname: Elit
authors.affiliation: University of Toronto, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Eileen
authors.initials: E
authors.lastname: Rakovitch
authors.affiliation: University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Fyles
authors.affiliation: University of Toronto, Toronto, Ontario, Canada; Department of Anatomic Pathology, University of Minnesota, Minneapolis, MN, United States.
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: Khalifa
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: University of Toronto, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Lisa
authors.initials: L
authors.lastname: Barbera
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006119:Groin / Q000601:surgery*; D006801:Humans; D008197:Lymph Node Excision; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D014846:Vulvar Neoplasms / Q000401:mortality / Q000601:surgery*
keywords: Competing risk; Groin; Nodes; Population; Survival; Vulvar cancer