title: Effect of Ovariohysterectomy at the Time of Tumor Removal in Dogs with Mammary Carcinomas: A Randomized Controlled Trial.
abstract: BACKGROUND
  Ovarian hormones play crucial roles in mammary carcinogenesis. However, whether ovarian ablation by ovariohysterectomy (OHE) improves the prognosis in dogs with mammary carcinomas is unclear.
  
  
  OBJECTIVE
  Determine if OHE at the time of mastectomy improves the prognosis in dogs with mammary carcinomas and evaluate if hormonal factors influence the effect of OHE.
  
  
  METHODS
  Sixty intact dogs with mammary carcinomas.
  
  
  METHODS
  Dogs were randomly assigned in a 1:1 ratio to undergo OHE (n = 31) or not (n = 29) at the time of tumor removal. Peri-surgical serum estradiol (E2) and progesterone concentrations were measured, tumor diagnosis was confirmed histologically, and tumor estrogen and progesterone receptor status was immunohistochemically determined. The dogs were monitored for recurrence and metastases every 3-4 months for at least 2 years. Uni- and multivariable survival analyses were performed with relapse and all-cause death as endpoints in addition to univariable subgroup analyses.
  
  
  RESULTS
  Overall, OHE did not significantly decrease hazard of relapse (hazard ratio [HR], 0.64; P = .18) or all-cause death (HR, 0.87; P = .64) in univariable analyses. In multivariable analysis OHE did not significantly influence the hazard of relapse (HR, 0.54; P = .12), but an interaction effect was identified between ER status and E2 (P = .037). Subgroup analysis identified decreased hazard of relapse in the OHE group compared to the non-OHE group in the subsets of dogs with increased E2 (HR, 0.22; P = .012) or grade 2 tumors (HR, 0.26; P = .02).
  
  
  CONCLUSIONS
  Dogs with grade 2, ER-positive tumors, or with increased peri-surgical serum E2 concentration represent a subset of dogs with mammary carcinomas likely to benefit from OHE.
authors.affiliation: Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
authors.forename: V M
authors.initials: VM
authors.lastname: Kristiansen
authors.affiliation: Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Peña
authors.affiliation: Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Díez Córdova
authors.affiliation: Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: Illera
authors.affiliation: Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Skjerve
authors.affiliation: Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
authors.forename: A M
authors.initials: AM
authors.lastname: Breen
authors.affiliation: Veterinary Specialty Center of Delaware, New Castle, DE, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Cofone
authors.affiliation: Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Langeland
authors.affiliation: Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Teige
authors.affiliation: School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Goldschmidt
authors.affiliation: School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: K U
authors.initials: KU
authors.lastname: Sørenmo
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D005260:Female; D007044:Hysterectomy / Q000662:veterinary*; D015674:Mammary Neoplasms, Animal / Q000601:surgery*; D010052:Ovariectomy / Q000662:veterinary*; D012307:Risk Factors; D055502:Secondary Prevention
keywords: Cancer; Canine; Malignant tumors; Spaying