Table 5

RR of breast cancer associated with use of postmenopausal hormone use according to tumor characteristics

CharacteristicNonusersEstrogen onlyEstrogen with progestin onlyP
CasesCasesRRa (95% CI)CasesRRa (95% CI)
Histology
 Ductal
  Ever hormone useb24466591.22 (1.06–1.41)2081.43 (1.14–1.79)
  Duration of use—all users1.02 (1.01–1.03)1.04 (1.00–1.08)0.2
   (continuous per year)cP = 0.001P = 0.03
  Duration of use—current users3931.01 (1.00–1.03)1731.03 (1.00–1.07)
   (continuous per year)cP = 0.008P = 0.07
 Lobular
  Ever hormone useb319891.19 (0.88–1.61)322.01 (1.25–3.22)
  Duration of use—all users1.03 (1.01–1.05)1.04 (0.97–1.11)0.7
   (continuous per year)cP = 0.01P = 0.3
  Duration of use—current users571.02 (1.00–1.05)301.04 (0.97–1.12)d
   (continuous per year)cP = 0.02P = 0.3
Extent of disease at diagnosis
 Local or stage I
  Ever hormone useb23426551.20 (1.04–1.38)2131.47 (1.18–1.84)
  Duration of use—all users1.02 (1.01–1.03)1.05 (1.02–1.09)0.05
   (continuous per year)cP = 0.001P = 0.002
 Nonlocalized or stage II–IV
  Ever hormone useb,e11282561.22 (1.01–1.47)831.50 (1.12–2.02)
  Duration of use—all users1.02 (1.00–1.03)1.01 (0.96–1.06)0.9
   (continuous per year)cP = 0.01P = 0.7
  • a Logistic regression models were conditional on age and state. RR was adjusted for age at menopause, type of menopause, age at first full-term pregnancy, body mass index, family history of breast cancer, education, screening mammography history, recent alcohol consumption, history of benign breast disease, age at menarche, and recent physical activity. Women who used both unopposed estrogen and estrogen-progestin are excluded.

  • b Reference category is nonusers including 4132 controls; 1027 controls used estrogen only, and 286 controls used estrogen and progestin only.

  • c Includes nonusers.

  • d In the test of the difference in RRs for the duration of current estrogen-progestin use in relation to ductal versus lobular breast cancer, χ2 = 3.35, 1 degree of freedom, P = 0.07.

  • e Model adjusted for all factors except screening mammography: estrogen alone only, RR, 1.09; 95% CI, 0.90–1.31; estrogen and progestin, RR, 1.26; 95% CI, 0.94–1.68. In the test of the difference in the RRs for the duration of estrogen only versus estrogen-progestin use.