title: Endometriosis-associated Ovarian Cancer: A Distinct Clinical Entity?
abstract: OBJECTIVE
  The aim of the study was to evaluate the incidence of endometriosis-associated ovarian cancer (EAOC) and compare clinicopathological characteristics and overall survival (OS) between patients with EAOC and those with ovarian cancer not associated with endometriosis.
  
  
  METHODS
  We identified EAOC among 203 patients with invasive epithelial ovarian cancer who underwent complete surgery at our Institution from January 2004 to March 2014.
  
  
  RESULTS
  EAOC was present in 45 patients. EAOC was significantly more frequently diagnosed at an earlier stage of disease (p=0.038). At a median follow-up time of 32 months, OS among patients with EAOC was significantly longer (p=0.039). However, stratifying by stage, the OS advantage of EAOC was not significant. At multivariate analysis, only stage was an independent prognostic factor for OS (hazard ratio=5.7; 95% confidence interval=1.8-18.6; p=0.003).
  
  
  CONCLUSIONS
  EAOC incidence was 22.2%. EAOC appears to be diagnosed at an earlier stage and confers a better OS. However, stratifying by stage, the advantage in survival of EAOC disappears.
authors.affiliation: Unit of Gynaecology and Obstetrics, Department of Surgical Science, University of Turin, Turin, Italy valentinabounous@hotmail.com.
authors.forename: Valentina E
authors.initials: VE
authors.lastname: Bounous
authors.affiliation: Unit of Gynaecology and Obstetrics, Department of Surgical Science, University of Turin, Turin, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Ferrero
authors.affiliation: Unit of Gynaecology and Obstetrics, Department of Surgical Science, University of Turin, Turin, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Fuso
authors.affiliation: Department of Pathology, Mauriziano Umberto I Hospital, Turin, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Ravarino
authors.affiliation: Department of Obstetrics and Gynaecology, Sacro Cuore Hospital, Negrar, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Ceccaroni
authors.affiliation: Unit of Gynaecology and Obstetrics, Department of Surgical Science, University of Turin, Turin, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Menato
authors.affiliation: Unit of Gynaecology and Obstetrics, Department of Surgical Science, University of Turin, Turin, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Biglia
mesh_terms: D017668:Age of Onset; D000368:Aged; D004715:Endometriosis / Q000401:mortality*; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000401:mortality*; D010051:Ovarian Neoplasms / Q000401:mortality*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies
keywords: Endometriosis-associated ovarian cancer; anatomo-pathological characteristics; prognosis