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Oestrogen replacement therapy and breast cancer risk: a case-control study
A L Weinstein1, M C Mahoney, P C Nasca
1Bureau of Cancer Epidemiology, New York State Department of Health, Albany 12237.
International Journal of Epidemiology
|October 1, 1993
Summary
This study found no overall link between estrogen replacement therapy and breast cancer risk. However, a potential increased risk was noted in specific subgroups after 10-19 years of use.
Area of Science:
- Epidemiology
- Oncology
- Hormone Therapy Research
Background:
- Estrogen replacement therapy (ERT) is used for menopausal symptoms.
- The association between ERT and breast cancer risk requires ongoing investigation.
- Population-based studies are crucial for understanding hormone therapy effects.
Purpose of the Study:
- To investigate the relationship between estrogen replacement therapy and breast cancer risk.
- To identify potential risk factors and subgroups associated with ERT use.
- To analyze confounding factors and interactions in ERT and breast cancer.
Main Methods:
- Population-based case-control study design.
- Inclusion of female residents aged 20-79 diagnosed with breast cancer.
- Age- and county-matched controls selected from driver's licence files.
Main Results:
- No significant association between ever-use of hormones and breast cancer risk in postmenopausal women.
- A significant risk elevation observed in women 10-19 years post-exposure, particularly in specific menopausal subgroups.
- A significant interaction between body mass index (BMI) and estrogen use was noted, affecting the thinnest tercile.
Conclusions:
- Overall, no clear link between ERT and breast cancer risk was established.
- Specific exposure durations and menopausal subgroups may warrant further investigation.
- The interaction with BMI suggests complex biological mechanisms requiring further study.
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