Hormone replacement therapy in women with breast cancer. Do the risks outweigh the benefits?
OBJECTIVE
To review critically the literature regarding effects of estrogen replacement therapy (ERT)/combined estrogen and progesterone replacement therapy (HRT) on the risk of breast cancer and on other health risks and benefits in postmenopausal women, with a focus on risks and benefits in women with a previous diagnosis of breast cancer.


METHODS
A literature search was conducted using Medline, Cancerline, and the bibliographies of reports published as of March 1995. All five published meta-analyses that examined the risk of breast cancer in relation to ERT/HRT in otherwise healthy women were critically reviewed. All known reports of women with a history of breast cancer given ERT/HRT subsequent to diagnosis and additional reports regarding the benefits of ERT/HRT were also reviewed.


RESULTS
None of the five meta-analyses demonstrated a significantly increased risk of developing breast cancer in ever users compared with never users of ERT/HRT. Current use may be associated with a small increased risk. This increased risk should be balanced by the expected benefits of ERT/HRT on quality of life, bone metabolism, and cardiovascular function. Preliminary information does not suggest a major detrimental effect of ERT/HRT in women with a previous diagnosis of breast cancer, but these reports include few women with limited follow-up data. There are no randomized trials in women with a previous diagnosis of breast cancer.


CONCLUSIONS
In healthy postmenopausal women, the benefits associated with ERT/HRT outweigh the risks. In women with a previous diagnosis of breast cancer, the balance of risks and benefits should be explored in randomized controlled trials.
Roy
J A
JA
Division of Medical Oncology/Haematology, Toronto-Sunnybrook Regional Cancer Centre, Ontario, Canada.
Sawka
C A
CA
Pritchard
K I
KI
D001943:Breast Neoplasms / Q000139:chemically induced*; D002318:Cardiovascular Diseases / Q000209:etiology / Q000517:prevention & control; D018592:Cross-Over Studies; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015201:Meta-Analysis as Topic; D009364:Neoplasm Recurrence, Local / Q000139:chemically induced*; D015663:Osteoporosis, Postmenopausal / Q000209:etiology / Q000517:prevention & control; D017698:Postmenopause / Q000187:drug effects / Q000502:physiology / Q000523:psychology; D011374:Progesterone / Q000008:administration & dosage / Q000009:adverse effects*; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D012306:Risk
D004967:Estrogens; D011374:Progesterone