Introduction: Postmenopausal women are already at risk for bone loss, osteoporosis and fractures due to low serum oestrogen levels. Adjuvant hormonal therapy with Aromatase Inhibitors (AI) can exacerbate this risk as AIs are potent inhibitors of oestrogen production. In women with oestrogen receptor (ER) positive breast cancer, AIs are used to reduce circulating oestradiol levels and in turn reduce breast cancer cell growth. However, the oestradiol deficient state causes increased bone remodelling and turnover. This results in bone loss, microstructural deterioration and bone fragility, predisposing to fractures.
Methodology: Evidence search from MEDLINE, EMBASE and COCHRANE was done. 2 guidelines and 3 systematic reviews, 2 primary data were found to be suitable. Evidence is summarised in this review and studies appraised to assess quality of evidence. Guidelines were appraised using the AGREE II tool and secondary and primary evidence were appraised via the CASP tool.
Results and Discussion: Weight bearing exercises, calcium and Vitamin D3 supplementation should be routinely recommended. Guidelines concur that baseline DEXA scan should be done for all women commencing AI therapy and repeated 12 months later to determine if bone mass loss. Pharmacological therapy should commence if any of the following criteria are met: T-score?
Conclusion: Strong evidence is available for the use of bisphosphonates, specifically zoledronic acid, in reducing AI induced bone loss. Alternatively, monoclonal antibody denosumab has been shown to reduce bone loss in the target population. In addition, a body of evidence suggests anti-cancer activity in early breast cancer with these drugs.
|