title: Prior appendectomy does not protect against subsequent development of malignant or borderline mucinous ovarian neoplasms.
abstract: BACKGROUND
  Due to concern that mucinous malignant or borderline ovarian neoplasms (MON) may represent metastatic deposits from appendiceal primaries, gynecologic oncologists routinely perform appendectomy in these cases. However, a multidisciplinary critique of this practice is lacking.
  
  
  METHODS
  The New England Case-Control study database was utilized to compare the effect of prior appendectomy against known risk factors for MON. Pathology and operative reports of local cases of MON were reviewed to estimate the frequency of microscopic mucinous lesions in the appendix. Protein expression patterns among mucinous ovarian, colorectal, and appendiceal cancers were compared by immunohistochemistry.
  
  
  RESULTS
  From the New England Case-Control study, 287 cases of MON were compared against 2339 age-matched controls. Prior appendectomy did not reduce the risk of MON (OR 1.28, 95% CI 0.83-1.92, p = 0.23), while prior tubal ligation, parity, and breastfeeding were each protective against MON. Active smoking (OR 2.04, 95% CI 1.48-2.80, p < 0.001) was associated with an increased risk of MON. Among 196 mucinous adnexal tumors, appendectomy did not reclassify any MON as appendiceal in origin. By immunohistochemistry, mucinous ovarian carcinomas tended to be CK7+/CK20-/MUC2-/CDX2-, whereas mucinous colorectal and appendiceal adenocarcinomas were typically CK7-/CK20+/MUC2+/CDX2+, although with some overlap in immunophenotype. Additionally, PAX8 was positive in a subset of MOC and negative in all appendiceal carcinomas.
  
  
  CONCLUSIONS
  Prior appendectomy is not protective against development of malignant or borderline MON. Routine appendectomy during surgery for MON seldom reveals an unsuspected GI primary in early stage tumors but may aid in final diagnosis in advanced stage cases.
  
  
  BACKGROUND
  National Cancer Institute grants P50-CA105009 and R21 CA-156021; The Honorable Tina Brozman 'Tina's Wish' Foundation; the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation (AMRF); Dana-Farber Cancer Institute - Susan Smith Center for Women's Cancers; Robert and Deborah First Fund; The Gamel Family Fund; Mary Kay Foundation; Sandy Rollman Ovarian Cancer Foundation; Arthur Sachs/Fulbright/Harvard; La Fondation Philippe; La Fondation de France.
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Division of Gynecologic Oncology, Department of Obstetrics and Gynecology and Reproductive Biology, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Elias
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
authors.forename: S Intidhar
authors.initials: SI
authors.lastname: Labidi-Galy
authors.affiliation: Obstetrics and Gynecology Epidemiology Center, Department of Obstetrics and Gynecology and Reproductive Biology, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Allison F
authors.initials: AF
authors.lastname: Vitonis
authors.affiliation: Harvard Medical School, Boston, MA, USA; Brigham and Women's Hospital, Department of Pathology, Boston, MA, USA.
authors.forename: Jason L
authors.initials: JL
authors.lastname: Hornick
authors.affiliation: Harvard Medical School, Boston, MA, USA; Brigham and Women's Hospital, Department of Pathology, Boston, MA, USA.
authors.forename: Leona A
authors.initials: LA
authors.lastname: Doyle
authors.affiliation: Harvard Medical School, Boston, MA, USA; Brigham and Women's Hospital, Department of Pathology, Boston, MA, USA; Brigham and Women's Hospital, Division of Women's and Perinatal Pathology, Boston, MA, USA.
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Hirsch
authors.affiliation: Obstetrics and Gynecology Epidemiology Center, Department of Obstetrics and Gynecology and Reproductive Biology, Brigham and Women's Hospital, Boston, MA, USA; Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Cramer
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Brigham and Women's Hospital, Department of Pathology, Boston, MA, USA; Brigham and Women's Hospital, Division of Women's and Perinatal Pathology, Boston, MA, USA. Electronic address: ronny_drapkin@dfci.harvard.edu.
authors.forename: Ronny
authors.initials: R
authors.lastname: Drapkin
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D001062:Appendectomy / Q000379:methods*; D014408:Biomarkers, Tumor / Q000378:metabolism; D000077216:Carcinoma, Ovarian Epithelial; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control*; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control*; D012307:Risk Factors
chemical_list: D014408:Biomarkers, Tumor
keywords: Appendectomy; Epidemiology; Mucinous ovarian neoplasms; Risk factors