title: Risk factors of epithelial ovarian carcinomas among women with endometriosis: a systematic review.
abstract: BACKGROUND
  The objective of this review was to evaluate the published literature on epidemiologic risk factors for epithelial ovarian cancer among women with a diagnosis of endometriosis.
  
  
  METHODS
  A systematic literature search was conducted in PubMed and Scopus. Studies comparing epidemiologic risk factors of epithelial ovarian cancer among women with endometriosis were included. A quality assessment was conducted using the Newcastle-Ottawa Scale.
  
  
  RESULTS
  Eight of 794 articles met the inclusion criteria. A lower risk of epithelial ovarian cancer was observed in women with documented complete surgical excision of endometriotic tissue and suggested among women with unilateral oophorectomy. The use of oral contraceptives (≥10 years) may be associated with a lower risk of epithelial ovarian cancer among women with endometriosis, whereas older age at endometriosis diagnosis (≥45 years, pre- or postmenopausal), nulliparity, hyperestrogenism (endogenous or exogenous), premenopausal status at endometriosis diagnosis, solid compartments as well as larger size of endometrioma (≥9 cm in diameter at endometriosis diagnosis) were all associated with an increased risk of ovarian cancer.
  
  
  CONCLUSIONS
  A subgroup of women with endometriosis characterized by endometriosis observed through surgery or imaging after the age of 45 years, nulliparity, postmenopausal status at endometriosis diagnosis, larger size of endometrioma (>9 cm) at endometriosis diagnosis, hyperestrogenism (endogenous or exogenous) and/or cysts with solid compartments may have an elevated risk of epithelial ovarian cancer. However, due to the limited number and size of studies in this area we cannot draw definitive conclusions. Further research into a risk factor profile among women with endometriosis is needed before clear recommendations can be made.
authors: Department of Gynecology and Obstetrics, Aarhus University Hospital, Aarhus, Denmark.
authors: Line H
authors: LH
authors: Thomsen
authors: Gynecologic and Obstetric Department, Rigshospitalet University Hospital of Copenhagen, Copenhagen, Denmark.
authors: Tine H
authors: http://orcid.org/0000-0002-6587-3772
authors: TH
authors: Schnack
authors: Oncologic Department, Aarhus University Hospital, Aarhus, Denmark.
authors: Kristina
authors: http://orcid.org/0000-0001-7666-352X
authors: K
authors: Buchardi
authors: World Endometriosis Research Foundation, London, UK.
authors: Lone
authors: L
authors: Hummelshoj
authors: Department of Obstetrics, Gynecology and Reproductive Biology College of Human Medicine, Michigan State University, Boston, MA, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors: Stacey A
authors: SA
authors: Missmer
authors: Department of Gynecology and Obstetrics, Aarhus University Hospital, Aarhus, Denmark.
authors: Axel
authors: A
authors: Forman
authors: Department of Gynecology and Obstetrics, Aarhus University Hospital, Aarhus, Denmark.
authors: Jan
authors: http://orcid.org/0000-0003-3726-0589
authors: J
authors: Blaakaer
mesh_terms: D000077216:Carcinoma, Ovarian Epithelial; D004715:Endometriosis / Q000150:complications*; D005260:Female; D006801:Humans; D009375:Neoplasms, Glandular and Epithelial / Q000175:diagnosis* / Q000209:etiology*; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000209:etiology*; D012307:Risk Factors; D016387:Women's Health
keywords: Endometriosis; epidemiology; ovarian cancer; risk factor; systematic review