Tamoxifen in postmenopausal women a safety perspective
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Published on: August 13, 2019
E Robinson1, G G Kimmick, H B Muss
1Comprehensive Cancer Center of Wake Forest University, Winston-Salem, North Carolina, USA.
Abstract:
Tamoxifen is a synthetic antiestrogen with both agonist and antagonist properties. It is believed to act primarily through binding to estrogen receptors in breast cancer cells, acting as a competitive inhibitor of estrogen. Tamoxifen has a wide range of systemic effects, possibly acting on every estrogen target tissue in the body. Tamoxifen therapy is associated with a significant reduction in the risk of recurrence and death in postmenopausal women with early stage breast cancer. In addition, it has been shown to effectively suppress preclinical breast cancer, as evidenced by the decrease in second primary breast cancers in adjuvant trials. Tamoxifen is also the most widely used endocrine therapy for women with metastatic breast cancer. Tamoxifen, acting predominantly as an estrogen agonist in the liver, has generally favourable effects on serum lipids in postmenopausal women. In addition, tamoxifen has been shown to preserve bone mineral density and may even decrease the risk of osteoporosis in these women. Most patients treated with tamoxifen have minimal adverse effects. Vasomotor symptoms are the most commonly reported events. Less frequently, vaginal discharge or dryness, nausea and depression have been reported. A slight increase in thromboembolic events in postmenopausal women taking tamoxifen has been suggested in some adjuvant trials. Rarely, ocular toxicity and hepatotoxicity are found. The adverse effect of primary importance is the increased incidence of endometrial carcinoma. Several studies indicate that almost all of the tumours are of low histological grade and stage, similar to those seen with exogenous estrogen use. The relative risk of endometrial cancer in women taking tamoxifen is about 2 to 4 times higher than for postmenopausal women not taking tamoxifen. The benefits of tamoxifen outweigh the risks in almost all postmenopausal women with estrogen receptor-positive early stage breast cancer and in all women with metastatic breast cancer. Should tamoxifen prove to be an effective chemopreventive agent for breast cancer, the risks and benefits of treatment will have to be more carefully assessed for this setting.
Insights
Tamoxifen therapy significantly reduces breast cancer recurrence and death in postmenopausal women. While generally safe, it carries a small risk of endometrial cancer, but benefits often outweigh risks for early-stage and metastatic breast cancer.
Area of Science:
- Oncology
- Endocrinology
- Pharmacology
Background:
- Tamoxifen is a synthetic antiestrogen used in breast cancer treatment.
- It acts as a competitive inhibitor of estrogen by binding to estrogen receptors.
- Tamoxifen exhibits both agonist and antagonist properties, leading to systemic effects.
Purpose of the Study:
- To evaluate the efficacy of tamoxifen in reducing breast cancer recurrence and mortality.
- To assess the systemic effects of tamoxifen, including its impact on lipids and bone density.
- To analyze the adverse effects associated with tamoxifen therapy, particularly endometrial carcinoma risk.
Main Methods:
- Review of clinical trial data on tamoxifen therapy in early-stage and metastatic breast cancer.
- Analysis of tamoxifen's effects on serum lipids, bone mineral density, and thromboembolic events.
- Evaluation of the incidence of endometrial carcinoma in women treated with tamoxifen.
Main Results:
- Tamoxifen therapy significantly reduces recurrence and death in postmenopausal women with early-stage breast cancer.
- It demonstrates favorable effects on serum lipids and preserves bone mineral density.
- The most significant adverse effect is an increased incidence of endometrial carcinoma (2-4 times higher risk).
Conclusions:
- Tamoxifen is a widely used and effective endocrine therapy for metastatic breast cancer.
- Its benefits, including reduced recurrence and improved lipid profiles, generally outweigh risks for most patients.
- Careful risk-benefit assessment is needed for potential chemopreventive use.
