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Published on: September 26, 2016
Adjuvant Endocrine Therapy and Bone Health in Breast Cancer
Gregory A Clines1, Palak Choksi, Catherine Van Poznak
1Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA, clines@umich.edu.
Abstract:
Breast cancer is one of the most common malignancies of women. The majority of breast cancers express estrogen and/or progesterone receptors, permitting anticancer targeting strategies to reduce estrogen signaling in the cancer cells and thereby lowering the risk of breast cancer recurrence. The development of the selective estrogen receptor modulator (SERM) tamoxifen marked a significant milestone in breast cancer care that transcended older estrogen ablative strategies such as oophorectomy and ovarian irradiation. An unintended benefit of tamoxifen in postmenopausal women was bone density preservation. The third generation of aromatase inhibitors (AIs) have demonstrated superior efficacy to tamoxifen in improving disease-free survival in postmenopausal women. However, the AIs significantly increase bone resorption, reduce bone mineral density, and increase the risk of fracture above that of tamoxifen. As a consequence of this, clinical oncologists have assumed a larger role in the screening and treatment of the skeletal complications of breast cancer therapies. The key features of managing bone health in women with early stage breast cancer receiving adjuvant endocrine therapy are reviewed here.
Insights
Selective estrogen receptor modulators (SERMs) like tamoxifen preserve bone density in breast cancer patients. Aromatase inhibitors (AIs) are more effective but increase bone loss and fracture risk, requiring oncologists to manage skeletal health.
Area of Science:
- Oncology
- Endocrinology
- Bone Metabolism
Background:
- Breast cancer often expresses hormone receptors, making endocrine therapy a cornerstone of treatment.
- Selective estrogen receptor modulators (SERMs) like tamoxifen were early successes, offering bone density benefits.
- Third-generation aromatase inhibitors (AIs) show improved efficacy over tamoxifen but pose risks to bone health.
Purpose of the Study:
- To review the management of skeletal complications in early-stage breast cancer patients undergoing adjuvant endocrine therapy.
- To compare the bone health effects of tamoxifen and aromatase inhibitors (AIs).
- To highlight the role of oncologists in addressing therapy-induced bone loss.
Main Methods:
- Review of clinical trial data comparing tamoxifen and aromatase inhibitors.
- Analysis of bone mineral density and fracture risk associated with endocrine therapies.
- Discussion of current clinical practices for bone health management in breast cancer patients.
Main Results:
- Aromatase inhibitors (AIs) demonstrate superior efficacy in improving disease-free survival compared to tamoxifen in postmenopausal women.
- AIs significantly increase bone resorption, reduce bone mineral density, and elevate fracture risk.
- Tamoxifen, in contrast, aids in preserving bone density.
Conclusions:
- Endocrine therapies for breast cancer have distinct effects on bone health.
- Aromatase inhibitors necessitate proactive management of skeletal complications due to increased bone resorption and fracture risk.
- Clinical oncologists play a crucial role in screening and treating bone-related side effects of breast cancer therapies.
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