title: Hormone therapy and the risk of breast cancer in BRCA1 mutation carriers.
abstract: BACKGROUND
  Hormone therapy (HT) is commonly given to women to alleviate the climacteric symptoms associated with menopause. There is concern that this treatment may increase the risk of breast cancer. The potential association of HT and breast cancer risk is of particular interest to women who carry a mutation in BRCA1 because they face a high lifetime risk of breast cancer and because many of these women take HT after undergoing prophylactic surgical oophorectomy at a young age.
  
  
  METHODS
  We conducted a matched case-control study of 472 postmenopausal women with a BRCA1 mutation to examine whether or not the use of HT is associated with subsequent risk of breast cancer. Breast cancer case patients and control subjects were matched with respect to age, age at menopause, and type of menopause (surgical or natural). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated with conditional logistic regression. Statistical tests were two-sided.
  
  
  RESULTS
  In this group of BRCA1 mutation carriers, the adjusted OR for breast cancer associated with ever use of HT compared with never use was 0.58 (95% CI = 0.35 to 0.96; P = .03). In analyses by type of HT, an inverse association with breast cancer risk was observed with use of estrogen only (OR = 0.51, 95% CI = 0.27 to 0.98; P = .04); the association with use of estrogen plus progesterone was not statistically significant (OR = 0.66, 95% CI = 0.34 to 1.27; P = .21).
  
  
  CONCLUSIONS
  Among postmenopausal women with a BRCA1 mutation, HT use was not associated with increased risk of breast cancer; indeed, in this population, it was associated with a decreased risk.
authors.affiliation: Sunnybrook Regional Cancer Center, Toronto, Ontario, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Eisen
authors.forename: Jan
authors.initials: J
authors.lastname: Lubinski
authors.forename: Jacek
authors.initials: J
authors.lastname: Gronwald
authors.forename: Pal
authors.initials: P
authors.lastname: Moller
authors.forename: Henry T
authors.initials: HT
authors.lastname: Lynch
authors.forename: Jan
authors.initials: J
authors.lastname: Klijn
authors.forename: Charmaine
authors.initials: C
authors.lastname: Kim-Sing
authors.forename: Susan L
authors.initials: SL
authors.lastname: Neuhausen
authors.forename: Lucy
authors.initials: L
authors.lastname: Gilbert
authors.forename: Parviz
authors.initials: P
authors.lastname: Ghadirian
authors.forename: Siranoush
authors.initials: S
authors.lastname: Manoukian
authors.forename: Gad
authors.initials: G
authors.lastname: Rennert
authors.forename: Eitan
authors.initials: E
authors.lastname: Friedman
authors.forename: Claudine
authors.initials: C
authors.lastname: Isaacs
authors.forename: Eliot
authors.initials: E
authors.lastname: Rosen
authors.forename: Barry
authors.initials: B
authors.lastname: Rosen
authors.forename: Mary
authors.initials: M
authors.lastname: Daly
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.forename: Steven A
authors.initials: SA
authors.lastname: Narod
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology* / Q000209:etiology* / Q000235:genetics; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D019398:Genes, BRCA1; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D016017:Odds Ratio; D017698:Postmenopause; D011372:Progestins / Q000008:administration & dosage / Q000009:adverse effects; D018570:Risk Assessment; D012307:Risk Factors; D018401:Sample Size; D011795:Surveys and Questionnaires
chemical_list: D004967:Estrogens; D011372:Progestins