Menopause, hormone replacement therapy and cancer.
OBJECTIVE
To comparatively review available evidence on hormone replacement therapy (HRT) and cancer.


METHODS
Qualitative literature review.


RESULTS
Most potential favorable and adverse effects on cancer risk of HRT are restricted to current users. On the basis of observational epidemiological data, the RR of breast cancer is moderately elevated in current and recent HRT users, and increases by about 2.3% per year with longer duration of use, but the effect drops after cessation and largely, if not totally, disappears after about 5 years. Unopposed estrogen use is strongly related to endometrial cancer risk, but cyclic combined oestrogen-progestin treatment appears to largely or totally reduce this side effect, if progestin are used for at least 14 days per cycle. However, combined HRT may be associated with higher risk of breast cancer as compared to unopposed estrogens. HRT has been inversely related to colorectal cancer, although the issue of causal relation remains open to discussion. No consistent association was reported for ovarian, liver, other digestive or lung cancer.


CONCLUSIONS
Recommendations for prolonged HRT use must be considered on an individual basis, taking into account the presence of other risk factors mainly for breast cancer, such as family history of breast cancer or a personal history of benign breast disease, as well as individual risk for other chronic diseases.
La Vecchia
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Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea 62, 20157 Milan, Italy. epidemiology@marionegri.it
Brinton
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LA
McTiernan
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D001943:Breast Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D015179:Colorectal Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D016889:Endometrial Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects* / Q000706:statistics & numerical data; D006801:Humans; D008593:Menopause; D010051:Ovarian Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D012307:Risk Factors