title: A population-based case-control study of canine mammary tumours and clinical use of medroxyprogesterone acetate.
abstract: We investigated whether or not an association could be found between mammary tumours and prior clinical use of medroxyprogesterone acetate (MPA) in bitches. A population-based retrospective age-matched case-control study was designed based on interviews with the owners of the bitches. The proportion of bitches with diagnosed mammary tumours (group MT+, n = 98) that had received progestin injections was compared with the proportion in a control group without mammary tumours (group MT-, n = 98). In the case group 39%, and in the control group 21% of the bitches had been treated with MPA. A significantly higher number of bitches with mammary tumours had been exposed to progestins, compared with the control group without mammary tumours (odds ratio = 2.32, Chi-square = 7.01, p = 0.008). Bitches treated clinically with low doses of MPA to avoid oestrus were at a greater risk of developing mammary tumours, the majority of which were histologically malignant (91%).
authors.affiliation: Department of Morphology, Norwegian College of Veterinary Medicine, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Støvring
authors.forename: L
authors.initials: L
authors.lastname: Moe
authors.forename: E
authors.initials: E
authors.lastname: Glattre
mesh_terms: D000367:Age Factors; D000818:Animals; D003271:Contraceptive Agents, Female / Q000009:adverse effects*; D004283:Dog Diseases / Q000209:etiology*; D004285:Dogs; D005260:Female; D007407:Interviews as Topic; D015674:Mammary Neoplasms, Animal / Q000209:etiology*; D017258:Medroxyprogesterone Acetate / Q000009:adverse effects*; D009664:Norway; D011153:Population; D012189:Retrospective Studies; D013045:Species Specificity
chemical_list: D003271:Contraceptive Agents, Female; D017258:Medroxyprogesterone Acetate