Tamoxifen, hormone receptors and hormone replacement therapy in women previously treated for breast cancer: a cohort study.
OBJECTIVE
To determine the risk of recurrence of breast cancer associated with the use of hormone replacement therapy (HRT) in the management of menopausal symptoms in women previously treated for breast cancer who were taking concurrent tamoxifen or who were estrogen receptor-positive.


METHODS
The study group comprised 1472 women with histologically confirmed breast cancer, of whom 342 subjects (23.2%) elected to use hormonal therapy in the management of their menopausal symptoms. Women were not excluded from treatment with hormonal therapy if they were taking adjuvant tamoxifen or if they had receptor-positive breast cancer. The response of these patients was compared with that of the rest of the database. A Cox regression analysis was performed with sex hormone usage as time-dependent covariate. Disease-free interval was the outcome measured.


RESULTS
Subjects who took concurrent tamoxifen with combined continuous estrogen-progestogen therapy had a hazard ratio of 0.67 (95% confidence interval (CI) 0.14-3.24, p = 0.62), while concurrent tamoxifen and topical vaginal estrogen users had a hazard ratio of 0.31 (95% CI 0.10-2.57, p = 0.28). The hazard ratio for the estrogen-progestogen users who were estrogen receptor-positive was 0.24 (95% CI 0.10-1.49, p = 0.14).


CONCLUSIONS
The use of HRT was not associated with an increased risk of recurrence of breast cancer in women taking concurrent tamoxifen or who were estrogen receptor-positive.
Dew
J E
JE
School of Women's and Children's Health, University of New South Wales, Royal Hospital for Women, Randwick, Australia.
Wren
B G
BG
Eden
J A
JA
D000279:Administration, Cutaneous; D000282:Administration, Intravaginal; D000284:Administration, Oral; D001943:Breast Neoplasms / Q000209:etiology* / Q000401:mortality* / Q000517:prevention & control; D015331:Cohort Studies; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006801:Humans; D009376:Neoplasms, Hormone-Dependent / Q000209:etiology / Q000401:mortality / Q000517:prevention & control; D009517:New South Wales / Q000453:epidemiology; D011372:Progestins / Q000008:administration & dosage* / Q000009:adverse effects; D016016:Proportional Hazards Models; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D012008:Recurrence; D012307:Risk Factors; D020845:Selective Estrogen Receptor Modulators / Q000008:administration & dosage; D013629:Tamoxifen / Q000008:administration & dosage*
D004967:Estrogens; D011372:Progestins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D020845:Selective Estrogen Receptor Modulators; D013629:Tamoxifen